TWI838543B - Probe head that can be used for both high frequency and medium and low frequency signal testing - Google Patents

Abstract

A probe head includes a probe holder, a first spring probe penetrating the upper, middle and lower guide plates of the probe holder to transmit a first test signal, and at least two second spring probes shorter than the first spring probes, penetrating the lower guide plate and used to transmit a second test signal with a higher frequency, wherein the top ends of the second spring probes abut against two conductive contacts connected to a connecting circuit inside the lower surface of the middle guide plate. The lower guide plate is provided with a connecting space and at least two lower mounting holes connected to the connecting space, and a second spring probe partially located in the connecting space is penetrated in each lower mounting hole; thereby, the probe head can be used for high-frequency and medium- and low-frequency signal testing at the same time, and can meet the requirements of fine spacing and high-frequency testing at the same time, and can avoid the circuit design of the probe card being too complicated.

Description

Probe head that can be used for both high frequency and medium and low frequency signal testing

The present invention relates to a probe head of a probe card, and in particular to a probe head that can be used for testing high frequency and medium and low frequency signals at the same time.

Due to market demand, the packaging and testing of integrated circuits (ICs) are developing towards fine pitch and high frequency. However, for vertical probe cards (VPCs), due to the limitations of the tester or cost considerations, or the probe length is too long, the test frequency cannot be increased. Therefore, in terms of high-frequency testing, some probes in the probe card are currently mainly used for loopback testing, that is, the transmission contacts (TX) and receiving contacts (RX) of the device under test (DUT; that is, the aforementioned IC) itself send and receive high-frequency signals, and the DUT itself performs signal detection, that is, the high-frequency test signal is not generated by the tester and is not transmitted to the tester. It should be noted that the signal described in this manual can be a digital signal or an analog signal.

In the case of vertical probe cards using spring probes (also called pogo pins), in order to meet the requirements of fine pitch and high frequency testing, spring probes (including molded spring probes, MEMS spring probes, and spring probes made by other manufacturing methods) need to be designed in the direction of being thinner and shorter, that is, the outer diameter of the spring probe should be small and the length should be short. However, if the electrical properties, mechanical characteristics, force, operating stroke, service life, and other factors are taken into consideration, it is difficult to make the spring probe short if it is to be thin, and it is difficult to make it short if it is to be thin. In other words, it is difficult for the same spring probe to meet the requirements of fine pitch and high frequency testing at the same time.

The commonly used probe cards that can be used for high-frequency and medium- and low-frequency signal testing are mainly equipped with a switching circuit, so that the same set of probes can be switched to an electrical conduction mode for high-frequency loopback testing, and can also be switched to an electrical conduction mode for transmitting medium- and low-frequency test signals from the tester. Such probe cards are more complex in circuit design, and the probe size is difficult to meet the requirements of fine spacing in order to meet the requirements of high-frequency testing. Moreover, based on IC design considerations, the center pitch of contacts used for high-frequency signals is usually larger than the center pitch of contacts used for other signals. Therefore, even through the aforementioned circuit switching, it is still difficult to use the same probe for high-frequency testing and medium- and low-frequency testing.

In view of the above shortcomings, the main purpose of the present invention is to provide a probe head that can be used for both high-frequency and medium- and low-frequency signal testing, which can avoid the circuit design of the probe card being too complicated and can simultaneously meet the requirements of fine spacing and high-frequency testing.

To achieve the above-mentioned purpose, the probe head provided by the present invention is used to transmit a first test signal and a second test signal, the frequency of the second test signal is higher than the frequency of the first test signal, and the probe head includes a probe holder, a first spring probe, and at least two second spring probes. The probe holder includes an upper guide plate, a lower guide plate, and a middle guide plate disposed between the upper guide plate and the lower guide plate, the middle guide plate having a lower surface facing the lower guide plate and at least one conductive unit, the conductive unit including two conductive contacts disposed on the lower surface, and a connection circuit located inside the middle guide plate and electrically connected to the two conductive contacts. The first spring probe passes through the upper guide plate, the middle guide plate, and the lower guide plate to transmit the first test signal. The at least two second spring probes are penetrated through the lower guide plate to transmit the second test signal. Each of the second spring probes is shorter than the first spring probe and has a top end. The two second spring probes are electrically connected to each other by respectively pressing their top ends against the two conductive contacts of the same conductive unit. The lower guide plate has an upper surface facing the middle guide plate, a lower surface opposite to the upper surface, and at least one lower mounting hole unit penetrating the upper and lower surfaces of the lower guide plate. The lower mounting hole unit includes at least two lower mounting holes and a connecting space connecting the at least two lower mounting holes. Each of the lower mounting holes is penetrated by a second spring probe, and each of the second spring probes is partially located in the connecting space of the lower mounting hole unit. For example, the lower mounting hole unit includes a groove recessed from the upper surface of the lower guide plate to form the communication space, and the lower mounting hole of the lower mounting hole unit penetrates a bottom surface of the groove and the lower surface of the lower guide plate. Alternatively, each of the lower mounting holes includes an upper section and a lower section, and the communication space is located between the upper section and the lower section of each of the lower mounting holes, the upper section extends downward from the upper surface of the lower guide plate to the communication space, and the lower section extends upward from the lower surface of the lower guide plate to the communication space.

In other words, the probe head of the present invention is provided with a first spring probe which is longer and passes through the entire probe holder, and a second spring probe which is shorter and only passes through the lower guide plate, and the two second spring probes are electrically connected to each other through the connecting circuit inside the middle guide plate (such as the internal wiring of a multi-layer circuit board, or the internal wiring plus electronic components, etc.). In this way, the at least two second spring probes can be used to touch the high-frequency signal transmission contact (TX) and receiving contact (RX) of the object to be tested, that is, can be used for loopback test of high-frequency signals. For example, the middle guide plate may have a conductive unit for the two second spring probes to abut against, and the two second spring probes are a set of transmitting and receiving probes, which are respectively used to touch the transmitting and receiving contacts of the object to be tested, or the middle guide plate may have two conductive units for the two sets of transmitting and receiving probes (i.e., a total of four second spring probes) to abut against, the two conductive units are insulated from each other, the two second spring probes connected to each conductive unit are respectively used to touch the transmitting and receiving contacts of the object to be tested, and the second spring probes connected to the two conductive units are differential pairs, that is, the two conductive units and the two second spring probes connected thereto form a signal transmission path, and the two signal transmission paths are used to transmit differential signals with opposite phases. In addition, the first spring probe can be used to touch other contacts of the object to be tested, such as ground contacts, power contacts, and general low- and medium-frequency signal contacts. In this way, each second spring probe can be made shorter and thicker to meet the electrical requirements of high-frequency testing, and the first spring probe can be made longer and thinner to meet the requirements of fine spacing when there are multiple first spring probes, so as to meet the overall testing requirements of the IC. In addition, the connecting space of the mounting hole unit under the lower guide plate is connected to at least two of the lower mounting holes, so that at least two of the second spring probes are partially located in the connecting space of the same lower mounting hole unit, so that the capacitance and inductance matching can be achieved and the characteristics of the probe card can be improved, especially in the case where the four second spring probes are used to form a differential pair for transmitting differential signals, so that the two second spring probes that are not electrically connected to each other are located in the connecting space of the same lower mounting hole unit, which can achieve a better capacitance and inductance matching effect.

The detailed structure, features, assembly or use of the probe head provided by the present invention, which can be used for both high-frequency and medium- and low-frequency signal testing, will be described in the subsequent detailed description of the implementation method. However, those with ordinary knowledge in the field of the present invention should understand that the detailed description and the specific embodiments listed for implementing the present invention are only used to illustrate the present invention and are not used to limit the scope of the patent application of the present invention.

The applicant first explains that in the embodiments and drawings to be introduced below, the same reference numbers represent the same or similar elements or their structural features. Secondly, when it is mentioned that an element is disposed on another element, it means that the aforementioned element is directly disposed on the other element, or the aforementioned element is indirectly disposed on the other element, that is, one or more other elements are disposed between the two elements. When it is mentioned that an element is "directly" disposed on another element, it means that no other elements are disposed between the two elements. It should be noted that the elements and structures in the drawings are drawn for the convenience of illustration and are not drawn according to the actual proportions and quantities, and if it is possible in practice, the features of different embodiments can be applied interchangeably. Furthermore, the “high frequency” and “medium and low frequency” mentioned below refer to the signal transmission speed of the “high frequency” being higher than that of the “medium and low frequency”. For example, when the signal transmission speed of the “high frequency” is greater than or equal to 40 Gbps, the “medium and low frequency” is less than 40 Gbps. However, the present invention is not limited to the aforementioned values, that is, the signal transmission speed of the “high frequency” is not limited to greater than or equal to 40 Gbps.

Please refer to FIG. 1 , a probe head 10 provided by a first preferred embodiment of the present invention and which can be used for both high frequency and medium and low frequency signal testing includes a probe base 20 , a plurality of first spring probes 30 , a plurality of second spring probes 40 , and a positioning film 50 . The probe head of this embodiment and the following embodiments may actually be provided with quite a number of first spring probes 30 and second spring probes 40, and the number of first spring probes 30 is usually much greater than the number of second spring probes 40. The second spring probes 40 are electrically connected to each other in pairs, and two pairs of second spring probes 40 form a differential pair. In order to simplify the diagram and facilitate explanation, the diagram of the present invention only shows one first spring probe 30 and four second spring probes 40 forming a differential pair, and the description is based on the case where the probe head 10 is provided with one first spring probe 30 and four second spring probes 40.

The probe holder 20 includes an upper guide plate 21, a middle guide plate 22 and a lower guide plate 23. The upper and lower guide plates 21 and 23 in this embodiment and the following embodiments are respectively composed of a single plate body. However, each of the upper and lower guide plates 21 and 23 can be composed of multiple plates stacked together according to design and processing requirements, such as the lower guide plate 23 in Figures 9 and 10. Each of the upper and lower guide plates 21 and 23 has an upper surface 211, 231 and a lower surface 212, 232 that are substantially facing opposite directions. The middle guide plate 22 is disposed between the lower surface 212 of the upper guide plate 21 and the upper surface 231 of the lower guide plate 23.

In detail, the guide plate 22 in this embodiment includes a multi-layer circuit board 221, and the multi-layer circuit board 221 has an upper surface 221a and a lower surface 221b facing substantially in opposite directions. The upper surface 221a and the lower surface 221b of the multi-layer circuit board 221 are respectively facing the lower surface 212 of the upper guide plate 21 and the upper surface 231 of the lower guide plate 23. The multi-layer circuit board 221 can be a multi-layer ceramic substrate (MLC), a multi-layer organic substrate (MLO), or other circuit substrates composed of a dielectric layer (such as resin, bakelite, glass fiber, plastic, etc.) and a metal layer (such as copper foil, etc.).

The upper, middle and lower guide plates 21, 22 and 23 respectively have a plurality of upper, middle and lower through holes 213, 223 and 233 (only one is shown in the drawings of the present invention), and the upper and lower through holes 213 and 233 respectively have a large diameter portion 213a and 233a equal to the inner diameter of the middle through hole 223 and a small diameter portion 213b and 233b smaller than the inner diameter of the large diameter portion 213a and 233a. The first spring probe 30 passes through one of the upper through holes 213, one of the middle through holes 223 and one of the lower through holes 233 which are coaxially corresponding to each other, that is, through the upper and lower surfaces of the upper, middle and lower guide plates 21, 22 and 23. In the present embodiment, the first spring probe 30 is a conventional spring probe, comprising an outer shell 31, a spring 32 disposed in the outer shell 31, and an upper needle shaft 33 and a lower needle shaft 34 respectively abutting against two ends of the spring 32 and extending out of the top and bottom ends of the outer shell 31, wherein the spring 32 is a conventional spiral spring machined. However, the first spring probe 30 of the present invention is not limited to the conventional spring probe as described above, but may also be a probe having a spring or other elastic structure machined by photolithography technology or other processing technology, so that the required elastic compression stroke and needle pressure can be obtained by setting the number of spring coils during processing. The portion of the lower needle shaft 34 of the first spring probe 30 protruding from the bottom end of the outer shell 31 passes through the small diameter portion 233b of the lower through hole 233, and the bottom end of the outer shell 31 abuts against the junction of the large and small diameter portions 233a, 233b of the lower through hole 233, thereby preventing the first spring probe 30 from falling out of the probe holder 20.

In addition to the aforementioned lower through hole 233, the lower guide plate 23 is further provided with a plurality of lower mounting hole units 24 (only two are shown in the figure of the present embodiment). As shown in FIG. 2 , each of the lower mounting hole units 24 includes a groove 241 recessed from the upper surface 231 of the lower guide plate 23, and two lower mounting holes 243 penetrating a bottom surface 242 of the groove 241 and the lower surface 232 of the lower guide plate 23. Each of the lower mounting holes 243 includes There is a large diameter portion 244 connected to the bottom surface 242 of the groove 241, and a small diameter portion 245 extending from the bottom end of the large diameter portion 244 to the lower surface 232 of the lower guide plate 23 (the inner diameter of the small diameter portion 245 is smaller than the inner diameter of the large diameter portion 244). Each lower mounting hole unit 24 is provided with two second spring probes 40 passing through the two lower mounting holes 243 respectively, and each second spring probe 40 is partially located in the groove 241. In the present embodiment, the second spring probe 40 is a conventional spring probe, comprising an outer shell 41, a spring 42 disposed in the outer shell 41, and an upper needle shaft 43 and a lower needle shaft 44 respectively abutting against two ends of the spring 42 and extending from the top and bottom of the outer shell 41, wherein the spring 42 is a conventional spiral spring machined. However, the second spring probe 40 of the present invention is not limited to a conventional spring probe, and may also be a probe having a spring or other elastic structure machined by photolithography technology or other processing technology. The lower needle shaft 44 of the second spring probe 40 passes through the small diameter portion 245 of the lower mounting hole 243, and the bottom end of the outer shell 41 of the second spring probe 40 abuts against the junction of the large and small diameter portions 244, 245 of the lower mounting hole 243, so as to prevent the second spring probe 40 from falling out of the probe holder 20.

The positioning film 50 is disposed between the lower surface 221b of the multi-layer circuit board 221 of the middle guide plate 22 and the upper surface 231 of the lower guide plate 23, and is provided with a plurality of positioning holes 51. The first and second spring probes 30 and 40 respectively pass through the positioning holes 51. Thus, the first and second spring probes 30 and 40 can be positioned by the positioning film 50 during implantation, making the assembly of the probe head 10 easier.

In this embodiment, the middle guide plate 22 has a plurality of conducting units 222 (only one is shown in the figure of this embodiment), and each two second spring probes 40 are electrically connected to each other through one of the conducting units 222. Each of the conducting units 222 includes two conductive contacts 224 located on the lower surface 221b of the multi-layer circuit board 221 and a connecting circuit 225 located inside the multi-layer circuit board 221. More specifically, the connecting The circuit 225 as a whole is an internal line located inside the multi-layer circuit board 221, that is, the connecting circuit (internal line) 225 is composed of layered wiring inside the multi-layer circuit board 221, the two conductive contacts 224 are respectively arranged at the two ends of the internal line 225 and are electrically connected to each other through the internal line 225, and the two second spring probes 40 are respectively electrically connected to each other by pressing their top ends 45 against the two conductive contacts 224. Each of the conductive units 222 forms a signal transmission path with two second spring probes 40 connected to its conductive contact 224, and the two pairs of second spring probes 40 shown in FIG. 1 and FIG. 2 constitute a differential pair, that is, FIG. 1 and FIG. 2 show four second spring probes 40 arranged in a matrix, and the four second spring probes 40 form two signal transmission paths with the two conductive units 222, and the two signal transmission paths are used to transmit differential signals with opposite phases (180 degrees difference). However, the second spring probes 40 of the present invention do not necessarily have to form a differential pair, that is, only one pair of second spring probes 40 electrically conductive to each other as shown in FIG. 1 can be retained, and each lower mounting hole unit 24 can have only a single lower mounting hole 243.

After the probe head 10 is assembled, the top end 35 of the first spring probe 30 protrudes from the upper surface 211 of the upper guide plate 21, and then the upper surface 211 of the upper guide plate 21 is fixed to a main circuit board (not shown in the figure), so that the probe head 10 and the main circuit board form a probe card, or the upper surface 211 of the upper guide plate 21 is fixed to a space converter (not shown in the figure), and the space converter is further fixed to A main circuit board (not shown in the figure) is formed so that the probe head 10, the space converter and the main circuit board form a probe card. At this time, the spring 32 of the first spring probe 30 is slightly compressed, so that the top end 35 of the first spring probe 30 shrinks into the upper through hole 213 and abuts against an electrical contact (not shown in the figure) of the main circuit board or the space converter. The main circuit board is used to be electrically connected to a tester (not shown in the figure). The so-called tester in this case, in a broad sense, can be a test machine used by an integrated circuit test factory to detect a test object, and further, it can also be a test instrument with a high-frequency transmission test signal.

Thus, when the bottom end 36 of the first spring probe 30 touches an electrical contact of the object to be tested (not shown in the figure), the first spring probe 30 can transmit a test signal between the tester and the object to be tested. Since the first spring probe 30 is longer, it is more suitable for transmitting ground signals, power signals and general medium and low frequency signals. In addition, the four second spring probes 40 are used in pairs as signal output probes (TX probes) and signal receiving probes (RX probes), respectively, for touching the high-frequency signal transmission contact (TX) and receiving contact (RX) of the object to be tested. More specifically, the two second spring probes 40 shown in FIG. 1 are represented as (+) TX probes and (+) RX probes, or (-) TX probes and (-) RX probes, and the two second spring probes 40 shown in FIG. 2 are represented as (+) TX probes and (-) TX probes, or (+) RX probes and (-) RX probes, wherein (+) and (-) indicate that the phases of the signals transmitted by the corresponding probes are positive and negative phases. In the case of non-transmitting differential signals, two second spring probes 40 electrically connected to each other by the conducting unit 222 as shown in FIG. 1 are used as signal output probes (TX probes) and signal receiving probes (RX probes), respectively, and their bottom ends 46 are used to touch the high-frequency signal transmission contacts (TX) and receiving contacts (RX) of the object under test. In this way, the high-frequency signal transmission contacts of the object under test can output high-frequency test signals and sequentially transmit them to the high-frequency signal receiving contacts of the object under test through one of the second spring probes 40 (TX probes), one of the conductive contacts 224, the internal circuit 225, another of the conductive contacts 224, and another of the second spring probes 40 (RX probes) to perform a loopback test of the high-frequency signal. Therefore, the second spring probe 40 can be manufactured to be shorter and thicker to meet the electrical requirements of high-frequency testing, and the first spring probe 30 can be manufactured to be longer and thinner to meet the requirements of fine spacing, thereby meeting the overall testing requirements of the IC.

From the above content, it can be known that the probe head 10 of the present invention uses the first spring probe 30 which is longer and passes through the entire probe base 20 to perform the medium and low frequency signal test, and uses the second spring probe 40 which is shorter and only passes through the lower guide plate 23 and the circuit of the middle guide plate 22 to perform the loopback test of the high frequency signal. In other words, the probe head 10 transmits a first test signal with a first spring probe 30 and transmits a second test signal with at least two second spring probes 40, wherein the frequency of the second test signal is higher than the frequency of the first test signal, that is, the first test signal is the aforementioned ground signal, power signal and general medium and low frequency signal, and the second test signal is the aforementioned high frequency signal.

As mentioned above, the present invention has no restrictions on the types of the first and second spring probes 30 and 40. However, the second spring probe 40 is much shorter than the first spring probe 30 in length. Therefore, no matter what type of spring probe is used for the second spring probe 40, its elastic compression stroke and needle pressure are more difficult to control. The first spring probe 30 is longer and its elastic compression stroke and needle pressure are easier to control. Therefore, it is convenient to make the elastic compression stroke and needle pressure of the first spring probe 30 match the elastic compression stroke and needle pressure of the second spring probe 40. In addition, several thick and short spring probes similar to the second spring probes 40 can be arranged around the second spring probes 40 to serve as grounding probes (not shown in the figure), and the grounding probes are electrically connected to the grounding line inside the middle conductor 22 (not shown in the figure), so that the transmission path of the high-frequency signal is surrounded by the transmission path of the ground signal, thereby making its electrical properties better.

In the embodiment shown in FIG. 1 and FIG. 2 , the second spring probes 40 that form a differential pair are partially located in the same groove 241 , so that the capacitance and inductance matching can be achieved and the characteristics of the probe card can be improved. The shape of the groove 241 is not limited. For example, the groove 241 can be circular or non-circular. The non-circular shape includes a quadrilateral (square, rectangle), a polygon or an irregular shape. The length of the shortest side of the quadrilateral, polygon or irregular shape or the diameter D of the circle is greater than the sum of the center distance (pitch) P of the second spring probe 40 (that is, the second spring probe 40 of the differential pair) in the same lower mounting hole unit 24 and the maximum diameter of the lower mounting hole 243 (in FIG. 2, the diameter of the large diameter portion 244, that is, twice the radius r of the large diameter portion 244), that is, D>P+2r. However, the lower guide plate 23 may also be formed as shown in FIG. 9 by stacking upper and lower plates 235 and 236 to form the aforementioned groove 241, that is, the lower mounting hole 243 for the single second spring probe 40 to pass through penetrates the top surface 237 and the bottom surface of the lower plate 236 (that is, the lower surface 232 of the lower guide plate 23), and the upper plate 235 is provided with an upper through hole 25 connected to the two lower mounting holes 243, so that the upper through hole 25 and the top surface 237 of the lower plate 236 together form the aforementioned groove 241, so that the two second spring probes 40 are partially accommodated in the groove 241. In this way, not only can the aforementioned effect of improving the characteristics of the probe card be achieved, but also the advantage of easy processing can be achieved.

In the state of the lower guide plate 23 shown in the aforementioned FIG. 2 and FIG. 9 , the lower guide plate 23 is provided with an open groove 241 on its upper surface 231, and a connecting space 26 is formed in the groove 241, so that the two second spring probes 40 that are a differential pair are partially located in the same connecting space 26, thereby improving the characteristics of the probe card. However, as shown in FIG. 10 , the connecting space 26 may also be formed inside the lower guide plate 23 instead of being open. Specifically, the lower guide plate 23 includes a lower plate 236, a middle plate 239 and an upper plate 235 stacked in sequence. Each of the lower mounting holes 243 includes an upper section 243a penetrating the upper plate 235 and a lower section 243b (including a large diameter portion 244 and a small diameter portion 245) penetrating the lower plate 236. The middle plate 239 is provided with a middle through hole 27 in which the connecting space 26 is formed. The connecting space 26 is located between the upper section 243a and the lower section 243b of each of the lower mounting holes 243. The upper section 243a extends downward from the upper surface 231 of the lower guide plate 23 to the connecting space 26, and the lower section 243b extends upward from the lower surface 232 of the lower guide plate 23 to the connecting space 26. In this way, the connecting space 26 hidden inside the lower guide plate 23 can also achieve the effect of improving the characteristics of the probe card as mentioned above, and in this way, the effect of the lower guide plate 23 supporting the probe is better. Similar to the aforementioned groove 241, the middle through hole 27 in FIG. 10 may also be circular or non-circular, wherein the non-circular shape includes a quadrilateral (square, rectangle), a polygon or an irregular shape, and the length of the shortest side of the quadrilateral, polygon or irregular shape or the diameter D of the circle is greater than the sum of the center distance P of the second spring probes 40 (i.e., the second spring probes 40 of a differential pair) in the same lower mounting hole unit 24 and the maximum diameter of the lower mounting hole 243 (in FIG. 10, the diameter of the large diameter portion 244, i.e., twice the radius r of the large diameter portion 244), i.e., D>P+2r.

It is worth mentioning that the connecting space 26 described in the present invention is a part of the lower mounting hole unit 24. The connecting space 26 is only directly connected to the lower mounting hole 243 included in the lower mounting hole unit 24 to which it belongs, and is not directly connected to the lower mounting hole 243 or the lower through hole 233 of the different lower mounting hole unit 24. Therefore, the connecting space 26 only accommodates the second spring probe 40. Moreover, the lower mounting hole unit 24 described in the present invention is defined as penetrating the upper surface 231 and the lower surface 232 of the lower guide plate 23, that is, the uppermost end of the lower mounting hole unit 24 is located on the upper surface 231. It can be seen from the drawings of the present invention that the lower guide plate 23 may (but not necessarily) have a space connecting all the lower mounting hole units 24 and the lower through holes 233. The space is located above the upper surface 231 of the lower guide plate 23, and all the first and second spring probes 30 and 40 are partially accommodated in the space. It can be seen that the space is not a part of a single lower mounting hole unit 24, nor is it connected to only the lower mounting hole 243 included in the single lower mounting hole unit 24. Therefore, the space above the upper surface 231 of the lower guide plate 23 cannot be regarded as the connecting space 26 described in the present invention. In other words, the portion of the probe (i.e., the second spring probe 40) used to transmit the high-frequency loopback test signal in the present invention located in the connecting space 26 is separated from the probe (i.e., the first spring probe 30 or the fourth spring probe 62 in FIG. 11) used to transmit the medium- and low-frequency signals, and a portion of the lower guide plate 23 is separated therebetween.

Please refer to FIG. 3 , a second preferred embodiment of the present invention is similar to the aforementioned first preferred embodiment, except that the middle guide plate 22 includes a multi-layer circuit board 221 and a machinable plate 226 (the material is, for example, machinable ceramic), the machinable plate 226 is disposed between the upper guide plate 21 and the lower guide plate 23, and the multi-layer circuit board 221 is fixed to a mounting surface 226a of the machinable plate 226 facing the lower guide plate 23 by gluing or screwing. The structure and function of the multi-layer circuit board 221 of this embodiment are the same as those of the multi-layer circuit board 221 of the first preferred embodiment described above, that is, a conducting unit 222 (including a conductive contact 224 and a connecting circuit 225) is provided to electrically connect the second spring probes 40 in pairs. However, the area and thickness of the multi-layer circuit board 221 of this embodiment are smaller, and it is indirectly connected to the upper and lower guide plates 21, 23 through the machinable plate body 226.

Since the electrical contacts of the object to be tested that transmit high-frequency signals are usually located near its edge, the second spring probe 40 used to transmit high-frequency signals is also usually located near the edge of the probe holder 20. In this case, the middle guide plate 22 has a block with a multi-layer circuit board 221 for the second spring probe 40 to abut against and a block with a middle through hole 223 for the first spring probe 30 to pass through, which is clearly separated, as shown in FIG. 3 . However, according to different test requirements, the first spring probe 30 may still need to be arranged around the second spring probe 40, or the distribution range of the second spring probe 40 may be intertwined with the distribution range of the first spring probe 30 without obvious separation. In this case, the shape of the multi-layer circuit board 221 can be designed to match the distribution of the first and second spring probes 30 and 40, such as shown in FIG. 4 and FIG. 5. A third preferred embodiment of the present invention is shown (FIG. 5 only depicts the outer contour of the multi-layer circuit board 221 but does not depict the conductive contacts 224). The area covered by the mounting surface 226a of the machinable plate 226 of the multi-layer circuit board 221 avoids the area with the middle through hole 223, so that the first spring probe 30 only passes through the machinable plate 226 but does not pass through the multi-layer circuit board 221. Alternatively, the area covered by the mounting surface 226a of the multi-layer circuit board 221 on the machinable board 226 may also cover one or more through holes 223, such as a fourth preferred embodiment of the present invention shown in FIGS. 6 and 7 (wherein FIG. 7 only depicts the outer contour shape of the multi-layer circuit board 221 and the through holes 223 but does not depict the conductive contacts 224), that is, the one or more through holes 223 penetrate the machinable board 226 and the multi-layer circuit board 221, so that the corresponding first spring probe 30 passes through the machinable board 226 and the multi-layer circuit board 221.

Please refer to FIG8 , a fifth preferred embodiment of the present invention is similar to the aforementioned second preferred embodiment, except that the machinable plate 226 of this embodiment has a groove 226b disposed on the mounting surface 226a, and the connecting circuit 229 of the middle guide plate 22 includes an electronic component 227 located on the upper surface 221a of the multi-layer circuit board 221 and located in the groove 226b, and two internal circuits 228 located inside the multi-layer circuit board 221 and electrically connected to the electronic component 227, the two internal circuits 228 are electrically connected to two conductive contacts 224 located on the lower surface 221b of the multi-layer circuit board 221, respectively, and the two second spring probes 40 are electrically connected to each other by respectively pressing their top ends 45 against the two conductive contacts 224. In this way, the high-frequency test signal outputted by the high-frequency signal transmission contact of the object to be tested is sequentially transmitted to the high-frequency signal receiving contact of the object to be tested through one of the second spring probes 40 (TX probe), one of the conductive contacts 224, one of the internal circuits 228, the electronic component 227, another of the internal circuits 228, another of the conductive contacts 224, and another of the second spring probes 40 (RX probe) to perform a loopback test of the high-frequency signal. The electronic component 227 can be a capacitor, an inductor, a resistor, or a combination of at least two thereof. Such a method of arranging the electronic component 227 is particularly suitable for situations where the electronic component needs to be arranged very close to the probe. The location of the electronic component 227 (i.e., the location of the groove 226b) is not limited to directly above the two second spring probes 40. Each of the internal circuits 228 can extend in any direction through the internal layered wiring of the multi-layer circuit board 221, so that the electronic component 227 can be set at any position on the upper surface 221a of the multi-layer circuit board 221 to enhance the configuration flexibility of the electronic component.

The aforementioned method of forming the connecting circuit 229 by the electronic component 227 and the two internal circuits 228 can also be applied to other types of the middle guide plate 22, as long as the middle guide plate 22 includes the processable plate body 226 and the multi-layer circuit board 221, for example, it can be applied to the middle guide plate 22 of the third and fourth preferred embodiments.

Similar to the first preferred embodiment, the internal circuits 225, 228 included in the connecting circuits 225, 229 that electrically connect the two conductive contacts 224 in the aforementioned second to fifth preferred embodiments are completely located inside the multi-layer circuit board 221, and the two conductive contacts 224 are arranged on the lower surface 221b of the multi-layer circuit board 221 and are respectively connected to the two ends of the internal circuit 225 or the two internal circuits 228, and the two second spring probes 40 are respectively electrically connected to each other by pressing their top ends 45 against the two conductive contacts 224.

As mentioned above, the probe head 10 of the present invention can simultaneously perform low- and medium-frequency testing and loopback testing of high-frequency signals by means of the longer first spring probe 30 and the shorter second spring probe 40. Therefore, the present invention can simultaneously be used for high-frequency and low- and medium-frequency signal testing without making the circuit design of the probe card too complicated, and can simultaneously meet the requirements of fine spacing and high-frequency testing.

In addition, as shown in FIG. 11 , in a sixth preferred embodiment of the present invention, the probe head 10 of the present invention can further form a structure similar to the first spring probe 30 by means of two shorter spring probes and the circuit inside the middle guide plate. In detail, this embodiment is similar to the first preferred embodiment described above, but the first spring probe 30 is not shown, and the probe head 10 of this embodiment further includes a third spring probe 61 passing through the upper guide plate 21, and a fourth spring probe 62 passing through the lower guide plate 23. The structures of the third and fourth spring probes 61, 62 are the same as the structures of the first and second spring probes 30, 40 described above, and the third and fourth spring probes 61, 62 are the same as the first and second spring probes 30, 40 described above. The lengths of the third and fourth spring probes 61 and 62 are approximately the same as the length of the second spring probe 40 and much shorter than the first spring probe 30. The third and fourth spring probes 61 and 62 are electrically connected to each other through another connecting circuit 63 inside the middle guide plate 22. In this embodiment, the connecting circuit 63 is a plated through hole with a conductive layer plated on the inner surface. The third and fourth spring probes 61 and 62 are electrically connected to each other by respectively contacting the upper and lower ends of the plated through hole 63 with their bottom ends and top ends. The structure composed of the third and fourth spring probes 61 and 62 and the connecting circuit 63 inside the middle guide plate 22 can also be used to transmit medium and low frequency signals or ground signals, and this structure can also be applied to the second to fifth preferred embodiments described above.

Finally, it must be reiterated that the constituent elements disclosed in the above-mentioned embodiments of the present invention are merely illustrative and are not intended to limit the scope of the present invention. Replacements or modifications of other equivalent elements should also be covered by the scope of the patent application of the present invention.

10: Probe head 20: Probe holder 21: Upper guide plate 211: Upper surface 212: Lower surface 213: Upper through hole 213a: Large diameter part 213b: Small diameter part 22: Middle guide plate 221: Multi-layer circuit board 221a: Upper surface 221b: Lower surface 222: Conductive unit 223: Middle through hole 224: Conductive contact 225: Connecting Circuit (internal circuit) 226: Machinable plate 226a: Mounting surface 226b: Groove 227: Electronic components 228: Internal circuit 229: Connecting circuit 23: Lower guide plate 231: Upper surface 232: Lower surface 233: Lower through hole 233a: Large diameter part 233b: Small diameter part 235, 236: (upper and lower) plate 237: Top surface 239: Middle plate 24: Lower mounting hole unit 241: Groove 242: Bottom surface 243: Lower mounting hole 243a: Upper section 243b: Lower section 244: Large diameter section 245: Small diameter section 25: Upper through hole 26: Connecting space 27: Middle through hole 30: First spring probe 31: Housing 32: Spring 33: Upper needle shaft 34 :Lower needle shaft 35:Top 36:Bottom 40:Second spring probe 41:Casing 42:Spring 43:Upper needle shaft 44:Lower needle shaft 45:Top 46:Bottom 50:Positioning film 51:Positioning hole 61:Third spring probe 62:Fourth spring probe 63:Connecting circuit (through hole) D:Length/diameter P:Center distance r:Radius

FIG. 1 is a schematic cross-sectional view of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by a first preferred embodiment of the present invention. FIG. 2 is a partial cross-sectional view of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by the first preferred embodiment of the present invention, along any section line 2-2 of FIG. 1. FIG. 3 is a schematic cross-sectional view of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by a second preferred embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by a third preferred embodiment of the present invention. FIG. 5 is a bottom view schematic diagram of a middle guide plate of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by the third preferred embodiment of the present invention. FIG. 6 is a cross-sectional schematic diagram of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by the fourth preferred embodiment of the present invention. FIG. 7 is a bottom view schematic diagram of a middle guide plate of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by the fourth preferred embodiment of the present invention. FIG. 8 is a cross-sectional schematic diagram of a probe head that can be used for high-frequency and medium-low frequency signal testing at the same time, provided by the fifth preferred embodiment of the present invention. FIG. 9 and FIG. 10 are similar to FIG. 2, but show different implementations of a lower guide plate of the probe head. FIG. 11 is a cross-sectional schematic diagram of a probe head provided by a sixth preferred embodiment of the present invention that can be used for both high-frequency and medium- and low-frequency signal testing.

10: Probe head

20: Probe holder

21: Upper guide plate

211: Upper surface

212: Lower surface

213: Upper perforation

213a: Main path

213b: small path

22: Middle guide plate

221:Multi-layer circuit board

221a: Upper surface

221b: Lower surface

222: Conductive unit

223: Middle piercing

224: Conductive contact

225: Connection circuit (internal circuit)

23: Lower guide plate

231: Upper surface

232: Lower surface

233: Bottom perforation

233a: Main path

233b: small path

243: Lower mounting hole

30: First spring probe

31: Shell

32: Spring

33: Needle shaft

34: Lower needle shaft

35: Top

36: Bottom

40: Second spring probe

41: Shell

42: Spring

43: Needle shaft

44: Lower needle shaft

45: Top

46: Bottom

50: Positioning film

51: Positioning hole

Claims (18)

A probe head that can be used for high-frequency and medium-low frequency signal testing at the same time is used to transmit a first test signal and a second test signal, the frequency of the second test signal is higher than the frequency of the first test signal, and the probe head includes: A probe base, including an upper guide plate, a lower guide plate, and a middle guide plate arranged between the upper guide plate and the lower guide plate, the middle guide plate has a lower surface facing the lower guide plate and at least one conductive unit, the conductive unit includes two conductive contacts arranged on the lower surface, and a connection circuit inside the middle guide plate and electrically connected to the two conductive contacts; A first spring probe, which passes through the upper guide plate, the middle guide plate and the lower guide plate to transmit the first test signal; and To At least two second spring probes are inserted through the lower guide plate to transmit the second test signal. Each of the second spring probes is shorter than the first spring probe and has a top end. The two second spring probes are electrically connected to each other by respectively pressing their top ends against the two conductive contacts of the same conductive unit; wherein the lower guide plate has an upper surface facing the middle guide plate, a lower surface relative to the upper surface, and at least one lower mounting hole unit penetrating the upper surface and the lower surface of the lower guide plate. The lower mounting hole unit includes at least two lower mounting holes and a connecting space connecting the at least two lower mounting holes. Each of the lower mounting holes is inserted with a second spring probe, and each of the second spring probes is partially located in the connecting space of the lower mounting hole unit. As described in item 1 of the patent application scope, the probe head can be used for both high-frequency and medium- and low-frequency signal testing, wherein the lower guide plate has two lower mounting hole units, and each of the lower mounting hole units is provided with two second spring probes that are differential pairs. As described in item 1 of the patent application scope, the probe head can be used for high-frequency and medium- and low-frequency signal testing at the same time, wherein the middle guide plate includes a multi-layer circuit board provided with the conductive contacts, and the connecting circuit includes at least one internal line inside the multi-layer circuit board. As described in item 3 of the patent application scope, the probe head can be used for high-frequency and medium- and low-frequency signal testing at the same time, wherein the connecting circuit is an internal line as a whole. As described in item 3 of the patent application scope, the probe head can be used for both high-frequency and medium- and low-frequency signal testing, wherein the middle guide plate further includes a machinable plate body, the machinable plate body has a mounting surface facing the lower guide plate, and the multi-layer circuit board is fixed to the mounting surface of the machinable plate body. As described in Item 5 of the patent application scope, the probe head can be used for both high-frequency and medium- and low-frequency signal testing, wherein the processable board has a groove arranged on the mounting surface, the multi-layer circuit board has a mounting surface facing the processable board and an upper surface of the groove, the connecting circuit includes an electronic component arranged on the upper surface of the multi-layer circuit board and located in the groove of the processable board, and two internal circuits electrically connected to the electronic component and respectively electrically connected to the two conductive contacts. As described in item 5 of the patent application scope, the probe head can be used for high-frequency and medium- and low-frequency signal testing at the same time, wherein the first spring probe passes through the machinable board and does not pass through the multi-layer circuit board. As described in item 5 of the patent application scope, the probe head can be used for high-frequency and medium- and low-frequency signal testing at the same time, wherein the first spring probe passes through the machinable board and the multi-layer circuit board. The probe head that can be used for high-frequency and medium- and low-frequency signal testing at the same time as described in Item 1 of the patent application scope further includes a positioning film arranged between the middle guide plate and the lower guide plate, and the first spring probes and the second spring probes respectively pass through a positioning hole of the positioning film. As described in Item 1 of the patent application scope, the probe head can be used for both high-frequency and medium- and low-frequency signal testing, wherein the lower mounting hole unit includes a groove recessed from the upper surface of the lower guide plate to form the connecting space, and the lower mounting hole of the lower mounting hole unit penetrates a bottom surface of the groove and the lower surface of the lower guide plate. As described in Item 10 of the patent application scope, a probe head that can be used for both high-frequency and medium- and low-frequency signal testing, wherein the groove of the lower mounting hole unit is non-circular, and the length of its shortest side is greater than the sum of the center distance of a second spring probe in the same groove and the maximum diameter of the lower mounting hole. As described in Item 10 of the patent application scope, a probe head that can be used for both high-frequency and medium- and low-frequency signal testing, wherein the groove of the lower mounting hole unit is circular, and its diameter is greater than the sum of a center distance of a second spring probe in the same groove and a maximum diameter of the lower mounting hole. As described in Item 10 of the patent application scope, a probe head that can be used for both high-frequency and medium- and low-frequency signal testing, wherein the lower guide plate includes a lower plate body and an upper plate body stacked on a top surface of the lower plate body, the lower mounting holes penetrate the top surface and a bottom surface of the lower plate body, the upper plate body is provided with an upper through hole, and the upper through hole and the top surface of the lower plate body together form a groove of the lower mounting hole unit. As described in Item 1 of the patent application scope, the probe head can be used for both high-frequency and medium- and low-frequency signal testing, wherein each lower mounting hole includes an upper section and a lower section, and the connecting space is located between the upper section and the lower section of each lower mounting hole, the upper section extends downward from the upper surface of the lower guide plate to the connecting space, and the lower section extends upward from the lower surface of the lower guide plate to the connecting space. As described in Item 14 of the patent application, a probe head that can be used for both high-frequency and medium- and low-frequency signal testing is provided, wherein the lower guide plate includes a lower plate body, a middle plate body, and an upper plate body stacked in sequence, the upper section and the lower section of each lower mounting hole respectively penetrate the upper plate body and the lower plate body, and the middle plate body is provided with a middle through hole to form the connecting space therein. As described in Item 15 of the patent application scope, a probe head that can be used for both high-frequency and medium- and low-frequency signal testing, wherein the middle through hole is non-circular, and the length of its shortest side is greater than the sum of a center distance of a second spring probe in the same middle through hole and a maximum diameter of the lower mounting hole. As described in Item 15 of the patent application scope, the probe head can be used for both high-frequency and medium- and low-frequency signal testing, wherein the middle through hole is circular, and its diameter is greater than the sum of a center distance of a second spring probe in the same middle through hole and a maximum diameter of the lower mounting hole. As described in item 1 of the patent application scope, the probe head can be used for both high-frequency and medium- and low-frequency signal testing, wherein the probe head further includes a third spring probe penetrating the upper guide plate, and a fourth spring probe penetrating the lower guide plate, and the third spring probe and the fourth spring probe are electrically connected to each other through another connecting circuit inside the middle guide plate.

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