DE10137669A1 - Method of aligning contact support onto countercontact support for chip test head - Google Patents

Abstract

The method contacts numerous contact points with numerous countercontact points. On a contact support surface is formed an adjusting contact (7), the surface contg. a positioning section (9) and a larger starting section (8), electrically conductively coupled.Next the contact points of the contact supports are aligned onto the counter contacts of the counter contact support by positioning each counter contact on the positioing section and starting section. The correct alignment of both contact supports is tested by specified short circuit testing.

Description

The invention relates to a method for contacting a Variety of contact points of a contact carrier with one Large number of mating contacts of a mating contact carrier.

Such methods are generally known and are described in used for example, the contact pins of a test head to contact the contact points of a wafer in order to to test the semiconductor chips formed on the wafer. The cost of the test makes up a significant part of the Ge total costs for the production of the semiconductor chips. The knockout However, most of the tests can be lowered if all are on semiconductor chips formed at the same time can be steady. There is therefore a need for a ver drive, with all the semiconductor chips on a wafer can be contacted at the same time. A so-called Wa fer-level test (WLT) requires thousands of contacts between contact points on the wafer counter contacts on egg a test head must be manufactured. Except decent high demands on the accuracy of the Aus Direction of the probe with respect to the wafer. Since the Kon clock positions on the wafer typically have a dimension of 90 µm × 90 µm, the wafers and the test head up to 30 to 40 µm in translation direction on each other be judged.

High accuracy is also required in the direction of rotation, because in this case the semiconductor chips near the edge of the wafer are more affected than the semiconductor chips in Zen of the wafer. For a wafer with a diameter of 200 mm the maximum tolerable offset angle is 0.013 Degree.  

The invention is based on this prior art the task of specifying a method with which a plurality of contact points of a contact carrier on egg ne variety of mating contacts of a mating contact carrier with aligned with high accuracy.

According to the invention, this object is achieved by a method with the following method steps:

• - Forming an alignment contact on a contact carrier surface with a positioning section and one in ver equal to the positioning section larger area fan gabschnitt that electrically with the positioning section tend is connected;
• - Align the contact points of the contact carrier on the Mating contacts of the mating contact carrier by positioning each because of a mating contact on the positioning section and the capture section;
• - Check the correct alignment of the contact carrier regarding the mating contact carrier by a short circuit test between the two on the positioning section and mating contacts positioned in the catching section.

The contact area has a large capture area cut open. This ensures that even with a rough positioning of the contact carrier in relation to the Ge gene contact carrier at least the intended counter con comes to rest on the capture section. The short final check is successful if the second counterpart clocks on the small positioning section, the connected to the contact surface comes to rest. Since the wide capture section and the narrow positioning section are electrically connected to each other, the La ge of the contact carrier with respect to the mating contact carrier by a short-circuit test between those at the position kidney section and mating section lying against the catch section clocks are determined.  

In a preferred embodiment, the adjustment contacts te T-shaped, the crossbar broadly trained is det and takes over the function of the capture section.

At least two of these T-shaped adjustment contacts must be used be formed on the contact carrier surface to the position of the contact carrier with respect to the mating contact carrier set.

It is particularly advantageous while two of the T- shaped adjustment contact opposite each other on the rän of the contact carrier surface are arranged because of the position of the contact carrier in relation to the counter contact carrier in this case by short-circuit tests on opposite Adjustment surfaces can be determined in a simple manner.

In a further preferred embodiment, outer Positioning sections of an adjustment contact around a centra len positioning section arranged around.

This arrangement has the advantage that only two of them Adjusting contacts formed on the contact carrier surface must be to the position of the contact carrier in relation to the To determine counter contact carrier.

Further details are the subject of the dependent claims che.

The invention is explained in more detail below with reference to the beige added drawing explained. Show it:

. Figure 1 shows the typical surface of a wafer as well as being enlarged views of the pads led contact locations on the wafer and the mating contacts of a probe;

Fig. 2 is a plan view of the surface of a converted wafer and enlarged views of the contact points and the counter-contacts designed as pads of the test head;

Figs. 3A to C Views on the surface of a wafer showing Conclusions The various types of Fehljustie;

FIGS. 4A and B are each a view of a clock Justierkon and associated mating contacts ei nes probe;

Fig. 5 is a perspective view of the force applied to the mating contacts Justierkontakt;

Fig. 6 is another perspective view of two adjustment contacts with the adjacent counter contacts and the associated test head lines;

Fig. 7A to D views of pairs of adjustment contacts and associated mating contacts with various misalignments;

Figure 8 is a plan view of a wafer surface with four on opposite sides of the Wa fers arranged Justierkontakten.

Figs. 9A and B are plan views of the wafer of Figure 8 in the x-direction offset probe.

. Figs. 10A and B are plan views of the wafer of Figure 8 in the y-direction offset test head;

FIG. 11A and B are plan views of the wafer of Figure 8 with twisted probe.

FIG. 12 is a plan view of the wafer from FIG. 8 with the test head offset in the x and y directions;

FIG. 13 is a plan view of the wafer of Figure 8 with twisted and offset test head.

FIG. 14 is a perspective view of another arrangement of the Justierkontaktes, more positioning portions are disposed at a central positioning around;

Fig. 15 is a plan view of one provided with the positioning contacts from Fig. 14;

FIG. 16A and B are plan views of the wafer of Figure 15 with an offset in the x-direction test head.

Figure 17 is a plan view of the wafer of Figure 15 with twisted probe..; and

FIG. 18 shows a further plan view of the wafer from FIG. 15 with the test head rotated and offset.

Fig. 1 shows a plan view of a wafer 1 is formed on which a plurality of semiconductor chips 2, which are still in the wafer composite. The only later to singulate the semiconductor chips 2 have 3 contact points 4 on the wafer surface, which are also referred to in the art as "pads". A number of such contact points 4 is drawn enlarged in FIG. 1. In order to test all semiconductor chips 2 in the wafer 1 simultaneously, all contact points 4 of counter contacts 5 of a test head 6 must be clocked. In Fig. 1 only a section of the test head 6 is shown with the counter contacts 5 , which serve to contact the enlarged contact points 4 on the wafer surface 3 .

It is also possible, as shown in FIG. 2, to carry out the contact points 4 arranged on the wafer 2 in an elevated manner. In this case, the counter contacts 5 of the test head 6 can be designed as flat, flat contacts (“pads”).

Since the contact points 4 have external dimensions of less than 90 μm × 90 μm, the error tolerance for lateral deviations of the test head 6 with respect to the wafer 1 is approximately 30 to 40 μm. In Fig. 3A, for example, the situation is drawn that the test head 6 is offset in an x-direction and y-direction with respect to the wafer. In contrast, in FIG. 3B, the test head 6 is positioned exactly on the wafer 1 for comparison. In this case, the counter contacts 5 come to lie exactly on the contact points 4 . But also a rotation of the test head 6 relative to the wafer 1 leads to the fact that the counter contacts 5 are no longer on the contact points 4 . In this case, in particular in the case of externally located semiconductor chips 2, there is the risk that the counter contacts 5 of the test head 6 will no longer come to rest on the contact points 4 of the respectively assigned semiconductor chip 2 . For a wafer with a diameter of 200 mm, the maximum tolerable angular deviation is therefore less than 0.013 degrees, for example.

In order to enable precise alignment of the test heads 6 on the wafer, provision is made to provide shaped adjustment contacts 7 on the wafer surface 3 in a special manner, which include both a wide capture section 8 and a narrow positioning section 9 . The adjustment contact 7 shown in FIG. 4A is essentially T-shaped, the crossbar serving as a capture section 8 . The positioning section 9 , however, is formed by a section of the support bar of the T-shaped adjustment contact 7 . The electrically conductive connection between the po sitioning sections 9 and the trapping section 8 is formed by a connector 10 . The essential direction of expansion of the sections 9 , 10 is perpendicular to the main connection direction of the section 8 . The connecting piece 10 is formed wider than the section 9 .

The outer dimensions of the positioning section 9 , in particular the width b, should not be greater than the outer dimensions of the contact points 4 on the wafer 1 . The outer dimensions of the capture section 8 , in particular its width B, must be larger than the outer dimensions of the contact points 4 on the wafer. The external dimensions of the contact points 4 are to be understood as their length dimension in the direction of the width b and B.

On the side of the test head 6 the adjustment contact 7 Ju bull pins 11 are assigned, which are referred to below with a, b, c and d, respectively. The adjustment pin 11 a comes with exact alignment of the test head 6 on the wafer 1 to lie on the positioning section 9 , while the adjustment pin 11 b on the capture section 8 of the adjustment contact 7 comes to lie. The alignment pins 11 d and 11 c are in the exactly positioned state of the wafer 1 and test head 6 next to the connecting piece 10 . In principle, the alignment pins 11 are b to 11 d in the vicinity of the portions 9, 10 are arranged, that is, either on the sections 9 or 10 or in the immediate vicinity laterally deviated. The exact positioning of the Prüfkop fes 6, with the aid of the probe 6 trained test head cables to be checked 12th For this purpose, the contacts 7 are arranged in pairs on the wafer 1 . In Fig. 6, such a pair of adjustment contacts 7 is shown in a per perspective view. The test head lines 12 are connected to the alignment pins 11 in such a way that a short-circuit test can be carried out as efficiently as possible for checking the position of the wafer 1 in relation to the test head 6 . So a probe line 12 b to the two adjustment pins 11 b is connected so that a short circuit test between the adjustment pins 11 b and the outer adjustment pins 11 a, the position of which on the positioning section 9 of the bull contacts 7 can be determined. In addition, a deviation from the desired location can be determined by a short circuit between the line 12 b and one of the lines 12 c or 12 d.

This is explained in more detail below with reference to FIGS. 7A to 7D. In the case shown in FIG. 7A, the test head 6 is exactly aligned with respect to the wafer 1 . Accordingly, the adjustment pins 11 a and 11 b are short-circuited, while between the adjustment pin 11 b and the adjustment pins 11 c and 11 d arranged laterally next to the connector 10 c there is no electrically conductive connection.

In Fig. 7B, the wafer 1 is offset from the test head 6 in the x direction. As a result, there is not only a short circuit between the adjusting pins 11 a and 11 b, but also a short circuit between the adjusting pins 11 b and 11 d of the upper adjusting contact 7 and the adjusting pins 11 b and 11 c of the lower adjusting contact 7 .

In Fig. 7C, the case is finally shown that the test head 6 is rotated onswinkel with respect to the wafer 1 by a certain rotation. In this case, there is not only a short circuit between the adjusting pins 11 a and 11 b, but also between the adjusting pins 11 b and 11 d. The position of the wafer 1 with respect to the test head 6 can in principle be determined from the number and type of short circuits.

However, if the two Justierkontakte 8 arranged to anyone that the elongated positioning sections 9 lie with the ih ren longitudinal axes on a line, the position of the Po can sitionierabschnitte 9 not uniquely Festge in the y direction are inserted. In principle, it would be possible to determine the position of the test head 6 with respect to the wafer 1 with two positioning sections 9 if the positioning sections 9 of the alignment contacts 7 are not in line with their longitudinal axes, but it is expensive in this case to determine the type of deviation from the target position, in particular if no short circuit is detectable between the adjusting pins 11 a and 11 b.

It is therefore advantageous, as shown in FIG. 8, to provide a plurality of alignment contacts 7 on the wafer 1 . To differentiate the adjustment contacts 7 are referred to below with the letters T, R, B and L.

FIGS. 9A and 9B each show the case in which the test head is offset in relation to the wafer 1 in the x direction. If the probe is offset in the -x direction, there is a short circuit between the adjusting pins 11 c of the Justierkontak tes 7 T and the adjusting pin 11 d of the Justierkontaktes 7 B. Since the connection between the Justierkontakt 7 T and the Justierkontakt 7 B on Adjustment pins 11 b mediates, which are each in contact with the capture sections 8 of the adjustment contacts 7 T and 7 B.

In Fig. 9B, the case is shown that the probe 6 is shifted ge compared to the wafer 1 in the + x direction. As a result, the adjustment pin 11 d of the adjustment contact 7 T and the adjustment pin 11 c of the adjustment contact 7 B is short-circuited.

An offset in the x-direction can thus be determined by short-circuits at the adjusting contacts 7 T and 7 B, each of which is transverse to the direction of movement with the longitudinal axis of the positioning sections 9 .

A movement in the y direction, however, can be determined by short-circuits on the adjustment contacts 7 R and 7 L. In Fig. 10A, the situation is drawn in which the probe 6 in the -y direction is offset from the wafer 1. In this case, a short circuit between the adjusting pin 11 c of the adjusting contact 7 L and the adjusting pin 11 d of the Justierkon clock 7 R occurs. Conversely, in the event of an offset in the + y direction, a short circuit occurs between the adjusting pins 11 d of the adjusting contact 7 L and the adjusting pins 11 c of the adjusting contact 7 R. With a shift in the + y direction ent there is a short circuit between the adjusting pin 11 d of the Ju bull contact 7 L and the adjusting pin 11 c of the Justierkontak tes 7 R.

Finally, consider the case where the test head 6 is rotated by a small angle relative to the wafer 1 . In this case, the short circuits occur in all four adjustment contacts 7 . In particular, there is a short circuit between the adjustment pins 11 d and 11 b of the adjustment contacts 7 T and 7 B. Furthermore, there is a short circuit between the Ju bull pins 11 d and 11 b of the adjustment contacts 7 L and 7 R. When rotating in the opposite direction of rotation each because the adjustment pins 11 c and 11 b of the opposite adjustment contacts 7 T and 7 B or 7 L and 7 R short-circuited.

That there is a rotation of the test head 6 relative to the wafer 1 can thus be recognized by the fact that 7 shorts occur at all 4 Ju bull contacts. There are functionally identical adjustment pins with the adjustment pin 11 b short-circuited. If there is an offset only in the x or y direction, this can be demonstrated by the fact that two adjustment contacts opposite one another with respect to the center of the wafer have opposite short-circuit signatures. If there is an offset in the x and y directions, this can be determined by a superimposition of the short-circuit patterns explained with reference to FIGS . 9 and 10.

In Fig. 13 the case is shown that the test head 6 ge compared to the wafer 1 by a rotation and is also offset in the x direction. A pattern for the short-circuited adjustment pins 11 occurs, as is also shown in FIG. 11B. An evaluation of this pattern initially reveals that the position of the test head 6 relative to the wafer 1 must be corrected in the direction of rotation. After this correction, however, a pattern, as shown in FIG. 9B, will occur which indicates an offset in the + x direction of the test head 6 relative to the wafer 1 .

In the arrangement and design of the adjustment contacts 7 shown in Fig. 8, the correction of the offset must generally be done gradually. This can be avoided if, as shown in FIG. 14, several adjustment contacts 7 are arranged closely adjacent to one another. In this case, the offset of the test head 6 with respect to the wafer 1 can be determined much more precisely.

In Fig. 14, a plurality of positioning portions and a plurality of associated Einfangabschnitte of Justierkontaktes 7 are so arranged that the positioning portions 9 are arranged around a central positioning around 9 square. Connecting lines 13 , which correspond to the connecting piece 10 of the adjusting contact 7 shown in FIG. 4A, lead from the centrally arranged positioning sections to an individual capturing sections 8 , which are arranged around the positioning sections 9 . The positioning sections 9 are smaller in area than the capture sections 8 . The central positioning section 9 is referred to below as a '. The remaining positioning sections of the adjustment contact 7 are designated by the letters b to i. The adjustment contact is referred to overall as the adjustment arrangement 14 .

The position of the test head 6 with respect to the wafer 1 is determined in the adjustment arrangement 14 shown in FIG. 15 with the aid of adjustment pins 15 . The adjustment pins 15 are connected to test head lines 16 . The positioning section 9 a 'are two adjustment pins 15 a and 15 a' assigned, each of which is connected to probe lines 16 a and 16 a '. The remaining positioning sections 9 b to 9 e are each assigned an adjusting pin 15 b to 15 i, which is located in the exactly aligned state on the capture sections 8 b to 8 i. Therefore, if the test head 6 is exactly aligned with the wafer 1 , only a short circuit occurs between the test head lines 16 a 'and 16 a. Otherwise, a short circuit between the test head line 16 a 'and one of the test head lines 16 b to 16 i can be detected.

This adjustment arrangement 14 has the advantage that basically only two of these adjustment arrangements 14 are required on the wafer 1 in order to determine the position of the test head 6 with respect to the wafer 1 . However, in order to align the test head 6 exactly on the wafer 1 , a larger number of these adjustment arrangements 14 is nevertheless helpful.

In the wafer 1 shown in FIG. 15, for example, four of these adjustment arrangements 14 are present on the wafer surface 3 . The adjustment arrangements 14 are referred to below with the letters T, R, B and L. The Clearly ness half 15 are shown only the positioning portions 9 of the Justieranordnungen 14 in Fig.. The Posi tionierabschnitt is shown in FIGS . 14 to 18 ge by a mark in an outer corner. In addition, of the adjustment pins 15 only the central adjustment pin 15 a 'is shown.

The size ratio of positioning sections 9 , contact 4 and alignment pins 11 to the wafer 1 is not to scale in FIG. 15. However, the real operating cases can be reproduced on the basis of the representation. From Fig. 15 it can be seen that the positioning portions are formed in area klei ner than the contact points 4. This is necessary for a safe alignment of the counter contacts 5 on the contact 4 . Exactly as in the exemplary embodiments shown in FIGS . 8 to 13, the position of the test head 6 with respect to the wafer 1 is also developed in the exemplary embodiment from FIGS . 14 to 18 from the type of short circuits that occur.

In Fig. 16A, the case is shown, for example, that the probe is slightly offset with respect to the wafer 1 6. In this case reaches the central alignment pin 15 a 'in the Justieranord voltage 14 T between the positioning portions 9 a' and 9 f, the adjustment assembly 14 R between the positioning portions 9 a 'and 9 c, in the adjustment assembly 14 B between the positio nierabschnitte 9 a 'and 9 e and in the adjustment arrangement 14 L between the positioning sections 9 a' and 9 e. Depending on the exact position of the tip of the adjustment pins 15 a ', the Ju bull pin 15 a' can still come to rest on the positioning sections 9 a ', so that the short circuit between the test leads 16 a' and 16 a occurs. An evaluation of the measurements on the test head lines 16 therefore leads to the result that there is a short circuit between the test head lines 16 a and 16 a '. This means that the counter contacts 5 still come to rest on the contact points 4 . The test head determines which of the input sections 8 a,. , ., 8 i the adjustment pin 15 a touches down.

In Fig. 16B is the case, finally, shows that the offset between the probe 6 and the wafer 1 is so large that a f in the adjustment assembly 14 T of the alignment pin 15 on the positioning portion 9, in the adjustment assembly 14 R on the positioning portion 9 c, comes to rest in the adjusting arrangement 14 B on the positioning section 9 e and in the adjusting arrangement 14 L on the positioning section 9 h. In this case, in the adjustment assembly 14 T occurs a short-circuit between the Prüfkopfleitungen 16 a 'and 16 f, the adjustment assembly 14 R between the Prüfkopfleitungen 16 a' and 16 c, in the alignment 14 B arrangement between the Prüfkopfleitungen 16 a 'and 16 e and in the adjustment arrangement 14 L between the test head lines 16 a 'and 16 h. Therefore, the pattern of shorts indicates a displacement that is so large that the counter-contacts 5 are outside of the contact points. 5

It is desirable that the distance between adjacent positioning portions 9, for example, the positioning portions 9 a 'and 9 that the alignment pin 15a is so low f (Fig. 14),' not completely isolated th between the Positionierabschnit 9 a ', b 9, , , ., 9 i can come to rest. At least the distance must be so small that two adjacent po sitioning sections are contacted simultaneously, so that a corresponding signal is obtained in the test head. Otherwise, if the adjustment pin 15 a 'could be electrically insulated in the intermediate area between two adjacent positioning sections, then the test head would determine the positioning as permissible, although there is actually an impermissible offset.

A rotationally symmetrical pattern, however, results in an offset of the probe 6 relative to the wafer 1 in the direction of rotation. In the case shown in FIG. 17, the Ju bull pins 15 A in the adjusting arrangements 14 T, 14 R, 14 B, 14 L each migrated to the positioning section 9 e.

In the case shown in FIG. 18, in which the test head 6 is offset relative to the wafer 1 both in the direction of rotation and in the direction of translation, a characteristic pattern results for the short-circuited lines, from which the position of the test head 6 in can be calculated with reference to the wafer 1 .

It should be noted that in each of the FIGS. 16A to Fig. 18 cases shown in principle already two of the bull Ju assemblies 14 would have been sufficient to determine the orientation of the probe 6 with respect to the wafer 1. However, more than two of the adjustment arrangements 14 are advantageous since the accuracy of the position determination of the test head 6 may then increase under certain circumstances.

LIST OF REFERENCE NUMBERS

1

wafer

2

Semiconductor chip

3

wafer surface

4

contact points

5

countercontact

6

probe

7

Justierkontakt

8th

trapping

9

positioning

10

joint

11

Locating pins

12

Prüfkopfleitung

13

connecting line

14

adjusting arrangement

15

adjusting pin

16

Prüfkopfleitung

Claims (12)

1. A method of contacting a plurality of contact points ( 4 ) of a contact carrier ( 1 ) with a plurality of contact contacts ( 5 ) of a counter contact carrier ( 6 ) with the process steps:

• - Form a Justierkontakts ( 7 ) on a Kontaktträ ger surface ( 3 ) with a positioning section ( 9 ) and egg nem in comparison to the positioning section area size larger capture section ( 8 ) which is electrically conductively connected to the positioning section ( 9 );
• - Aligning the contact points ( 4 ) of the contact carrier ( 1 ) on the counter contacts ( 5 ) of the counter contact carrier ( 6 ) by positioning a respective counter contact ( 11 , 15 ) on the positioning section ( 9 ) and the catching section ( 8 );
• - Check the correct alignment of the contact carrier ( 1 ) with respect to the mating contact carrier ( 6 ) by a short circuit test between the two each on the Positionierab section ( 9 ) and the capture section ( 8 ) positioned Ge counter-contacts ( 11 , 15 ).

2. The method according to claim 1, in which further mating contacts ( 11 c, 11 d) are positioned outside the ju bull contact ( 7 ). 3. The method according to any one of claims 1 or 2, wherein the adjusting contact ( 7 ) is T-shaped. 4. The method according to claim 3, wherein the adjusting contact has a first section ( 8 ) pointing in a first direction and a second section ( 9 , 10 ) pointing in a second direction that is perpendicular to it, in the vicinity of the first section ( 8 ) has a greater width ( 10 ) than at an end ( 9 ) facing away from the first section ( 8 ). 5. The method according to claim 3 or 4, in which four mating contacts ( 11 a,..., 11 d) who positioned one of which is po sitioned in the region of the first section ( 8 ) and the other near the second From section ( 10 , 9 ) to be positioned. 6. The method according to claim 1 or 2, wherein the adjusting contact ( 7 ) has a plurality of outer positioning sections ( 9 b,..., 9 i) arranged around a central positioning section ( 9 a '). 7. The method according to claim 6, wherein the trapping sections ( 8 a,..., 8 i) are arranged around the outer positioning sections ( 9 b,..., 9 i), one connecting line ( 13 ) each from (9 a a Posi tionierabschnitt '..., 9 i) to a respective one of the outer positioning portions (9 a' (.. 8 a,., 8 i)..., 9 i) around been arrange th Einfangsabschnitte leads. 8. The method according to claim 7, in which on each of the capture sections ( 8 a,..., 8 i) a counter contact ( 15 a,..., 15 i) is positioned and exactly one further counter contact ( 15 a ') at least one of the positioning sections ( 9 a,..., 9 i) is positioned. 9. The method according to any one of claims 1 to 8, in which a plurality of adjusting contacts ( 7 ) are arranged at a distance over the con tact carrier ( 1 ) distributed. 10. The method according to claim 9, in which at least two adjusting contact ( 7 ) are arranged in the vicinity of the edge of the contact carrier and over the contact carrier ( 1 ). 11. The method according to any one of claims 1 to 10, in which a wafer ( 1 ) is used for the contact carrier. 12. The method according to any one of claims 1 to 11, in which a test head provided with contact pins ( 6 ) is used for the mating contact carrier.