CN100573825C - Chemical vapor deposition apparatus and method thereof - Google Patents

Abstract

The invention provides a kind of for spraying chemical vapor deposition unit and the method thereof that the engineering gas that is supplied in wafer improves the gas distribution face plate structure equably.For this reason, the present invention comprises the shower nozzle that the wafer that is used in process chamber distributes engineering gas, this shower nozzle comprises the gas distribution face plate that forms a plurality of gas blowing streams, and at least one stream comprises first stream from engineering gas to gas distribution face plate that begin to flow into and the direction of relative first stream tilts to form by certain angle for the flow direction that changes the engineering gas by first stream second stream in a plurality of gas blowing streams.At this moment, in order to make engineering gas by second stream and be diffused into wideer area, second stream can form the guide groove form.Structure in view of the above, even the present invention shortens the spacing between gas distribution face plate and the wafer in order to improve process efficiency, also can be with engineering gas uniform deposition to the whole surface of wafer, thereby have the effect that can make the high-quality wafer.

Description

Chemical vapor deposition apparatus and method thereof

technical field

The present invention relates to a chemical vapor deposition device and method used in a semiconductor manufacturing process, in particular to a chemical vapor deposition device and method with improved gas distribution panel structure for uniform injection of engineering gas supplied to wafers.

Background technique

Chemical vapor deposition (CVD), as one of the semiconductor process technologies, refers to the method of forming a single crystal semiconductor film or insulating film on the surface of a wafer by chemical reaction. A conventional thermal CVD process forms a predetermined thin film by supplying a reactive gas to a wafer surface and utilizing a heat conduction chemical reaction generated on the wafer surface. The plasma-enhanced CVD (PE CVD) technology forms plasma by applying high-frequency energy to the reaction area around the substrate surface, and the high reactivity of these plasmas reduces the energy required for chemical reactions, so it is used in Where the required process temperature is lower compared with the traditional CVD process. Since this advantage can be further improved by the high-density plasma CVD (HDP CVD) process, in order to make high-density plasma CVD have a higher ionization effect than plasma CVD, by applying an electric field and a magnetic field in a low-pressure vacuum state A high-density plasma is formed and a source gas is decomposed to deposit an insulating film on a wafer.

An apparatus generally used for a CVD process, having a process chamber for performing a predetermined process on a wafer, a susceptor for supporting the wafer, a gas supply source for supplying an engineering gas, and a device for distributing the engineering gas to the wafer inside the process chamber Gas distribution device in the upper part of the process chamber.

In this device, only when the engineering gas is evenly distributed on the wafer through the gas distribution device, can the deposition on the wafer surface be uniform and high-quality films be obtained. But on the other hand, the user who uses the device hopes to increase the workload by improving the process efficiency, and the process efficiency of the CVD device is largely affected by the distance between the gas distribution device and the wafer. That is, to increase process efficiency, the distance between the wafer and the gas distribution device should be as short as possible. However, if the distance between the wafer and the gas distribution device is shortened in consideration of process efficiency, it will cause streaks on the wafer or concentration of reaction gases on specific parts of the wafer, resulting in uneven deposition throughout. Therefore, there is a need for a further improved gas distribution device for evenly distributing process gas to reaction regions on a wafer even if the distance to the wafer is shortened for process efficiency.

The related US Patent No. 6,793,733 discloses a gas distribution showerhead comprising a panel with gas outlets in the form of elongated channels or grooves for the purpose of uniformly distributing the process gas to the interior of the process chamber. As shown in FIG. 1 a and FIG. 1 b , the disclosed gas distribution showerhead includes a baffle 1 with holes 1 a for radially diffusing engineering gas and a gas distribution panel 2 located below the baffle 1 . The inlet side of the panel 2 that accommodates the flow of the process gas that is approximately uniformly diffused and distributed through the baffle plate 1, that is, the upper surface of the panel 2 has a plurality of separated holes 3, and the gas outlet side of the panel 2 that transfers the process gas to the wafer W , that is, the lower surface of the panel 2 has several guide grooves 4 .

However, in this existing device, the gas flow paths formed on the gas distribution panel 2 have a linearly extending form, so there is a problem that the process gas cannot be evenly distributed when it flows to the wafer and is concentrated at the bottom of the central axis of each flow path. This problem is exacerbated if the distance between the gas distribution panel 2 and the wafer W is shortened in order to improve process efficiency. If the guide groove 4 is formed on the gas outlet side of the panel, the uniformity of gas distribution can be improved to some extent, but the gas flow in the process chamber basically has the movement characteristics of the up and down direction, so it cannot be a complete solution to the above problems. Methods.

And, as described in Figure 1b, the holes 3 of the gas distribution panel 2 are formed symmetrically with respect to the central axis of the panel, and the closer to the central axis of the panel 2, the distribution density of the holes 3 is larger, so that the engineering gas distributed to the wafer is concentrated in Problems near the center of the wafer.

Contents of the invention

In order to solve the above-mentioned problems, the present invention aims to provide a chemical vapor deposition apparatus and method for improving the structure of the gas distribution panel, so that even if the distance between the gas distribution panel and the wafer is shortened in consideration of process efficiency, A uniform thin film can be formed on the entire surface of the wafer.

In order to achieve the above object, according to the chemical vapor deposition device provided by the present invention, it includes a shower head for distributing engineering gas to the wafer inside the process chamber, and it is characterized in that the shower head includes a gas distribution panel (faceplate) forming a plurality of gas injection flow paths. ), at least one of the plurality of gas injection flow paths includes an inclined flow path formed at a certain angle relative to the initial flow direction of the engineering gas, so that the engineering gas passing through the gas distribution panel is dispersed in the horizontal direction and sprayed toward wafer.

In particular, at least one flow path among the plurality of gas injection flow paths includes a first flow path that starts to flow engineering gas into the gas distribution panel, and a direction relative to the first flow path is changed in order to change the flow direction of the engineering gas that has passed through the first flow path. The second flow path is formed by inclining at a certain angle, the second flow path extends from one end of the first flow path, and the formed second flow path has non-uniform directionality.

The angle θ (θ is an acute angle) of the second flow path inclined relative to the direction of the first flow path is as follows:

0°＜θ≤45°

As described above, the present invention distributes the process gas to the wafer uniformly by dispersing the flow direction of the process gas in the second flow path formed in the gas distribution panel.

The shape of the second flow path has an extended channel shape, so that the engineering gas can pass through the second flow path and be diffused to a wider area.

The length of the guide groove in the extending direction is greater than the length in the vertical direction, and at least communicates with more than one first flow path.

The extension direction of the guide groove is inclined at a certain angle relative to the circumferential direction of the gas distribution panel, so that the process gas can be distributed to the radial direction of the wafer when the wafer support device installed inside the process chamber for supporting the wafer rotates.

The inner surface of the second flow path has a conical shape in which the cross-sectional area of the flow path increases toward the outlet side of the second flow path.

In addition, the gas injection channel is formed on the gas distribution panel in a non-axisymmetric manner with respect to the central axis of the gas distribution panel.

Description of drawings

Figure 1a is a longitudinal sectional view showing an existing chemical vapor deposition device;

Figure 1b is a bottom surface perspective view showing the prior art gas distribution panel of the apparatus of Figure 1a;

Fig. 2 is a longitudinal sectional view showing a schematic structure of a chemical vapor deposition apparatus according to the present invention;

3 is a plan view showing the upper surface of the gas distribution panel according to one embodiment of the present invention;

Figure 4 is a bottom surface perspective view showing portion A of the gas distribution panel of Figure 3;

Fig. 5 is a side sectional view showing B-B' part in Fig. 4;

Fig. 6 is a partial perspective view showing a lower surface of another gas distribution panel for a chemical vapor apparatus according to the present invention.

Detailed ways

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Fig. 2 is a longitudinal sectional view showing a schematic structure of a chemical vapor deposition apparatus according to the present invention.

As shown in Figure 2, the chemical vapor deposition device according to the present invention is composed of an upper body 11 and a lower body 12, and includes: a process chamber 10 forming a sealed space for depositing a film on a wafer W; and being arranged through the lower body 12 And the wafer supporting device 20 that can make the wafer W rotate and constitute, so that the engineering gas sprayed to the wafer W side is deposited on the wafer W surface; the shower head 50 arranged through the upper body 11, and the shower head 50 includes a plurality of nozzles for forming the injection engineering gas. A gas distribution panel (faceplate) 40 for each gas injection channel 30. The wafer support device 20 may use a non-rotatable structure. The lower side of the lower body 12 forms a discharge port 13 for discharging reaction incidentals and unreacted gases in the process chamber 10, and a vacuum pump that can maintain a vacuum state inside the process chamber 10 is provided on the discharge pipe 14 connected to the discharge port 13 15 and pressure control device 16.

For this kind of chemical vapor phase device, if the process gas is supplied by a gas supply device (not shown) connected to the shower head 50, the process gas is distributed through the shower head 50 and sprayed onto the wafer W side located below it, thereby being processed. The injected engineering gas forms a predetermined thin film through a chemical reaction occurring on the surface of the wafer W. At this time, in order to increase throughput by improving process efficiency, it is necessary to make the distance (d) between the gas distribution panel of the showerhead and the surface of the wafer W as close as possible. However, since the engineering gas injected through the gas distribution panel has no room for injection, it concentrates on a specific part of the wafer W, especially directly below the central axis of the gas injection flow path, resulting in a decrease in the coating quality of the wafer. To this end, the present invention includes a gas distribution panel 40 having a gas injection flow path 30 designed to uniformly inject process gas to the wafer W even if the wafer W is positioned close to the gas distribution panel 40 on W. That is, at least one of the gas injection channels 30 of the present invention includes an inclined channel formed at a certain angle, so that the process gas passing through the gas distribution panel 40 is dispersed in the horizontal direction and sprayed onto the wafer. A gas distribution panel having a second flow path formed as an inclined flow path will be described below.

Fig. 3 is a plan view showing the upper surface of the gas distribution panel according to one embodiment of the present invention, Fig. 4 is a perspective view showing the bottom surface of part A of the gas distribution panel of Fig. 3, and Fig. 5 is a side section showing part B-B' of Fig. 4 picture.

As shown in FIGS. 3 to 5 , a plurality of gas injection flow paths 30 are formed in the gas distribution panel 40 of the present invention, and the upper surface 41 of the gas distribution panel 40 is formed for making engineering gas start to flow into the plurality of gas injection flow paths 30 The lower surface 42 of the gas distribution panel 40 forms a plurality of outlets 32a for spraying the process gas passing through each flow path onto the wafer W. At least one of the plurality of gas injection flow paths 30 includes the first flow path 31 through which the process gas starts to flow in through the inflow port 31a, and is opposite to the first flow path 31 in order to change the flow direction of the process gas that has passed through the first flow path 31. The direction of the flow path 31 is inclined at a certain angle to form the second flow path 32 . At this time, the second flow path formed has no uniform directionality, and as shown in FIG. 4 , it can be formed inclined in any direction from the first flow path. However, in FIG. 4 , the three flow paths arranged in a straight line only indicate that the second flow path is formed with a certain direction toward the center of the gas distribution panel 40 .

As mentioned above, the purpose of inclining the second flow path relative to the first flow path at a certain angle is to reflect the engineering gas passing through the first flow path 31 through the inner surface of the second flow path 32 to weaken the vertical direction velocity component of the engineering gas and at the same time make the engineering The gas has a velocity component in the horizontal direction when passing through the second flow path 32 , so that the process gas can be evenly distributed on the wafer W when the distance between the wafer W and the gas distribution panel 40 is close.

However, if the inclination angle of the second flow path 32 relative to the direction of the first flow path 31 is too large, the engineering gas passing through the first flow path 31 will encounter great resistance when entering the second flow path 32, which may cause injection of the engineering gas. Problems such as consuming a lot of energy and damaging the gas distribution panel 40 . Therefore, the inclination angle θ of the second flow path 32 relative to the direction of the first flow path 31 is preferably within the following range.

0°＜θ≤45°

As in the prior art shown in Figure 1b, if the gas injection flow path is formed symmetrically with respect to the central axis of the gas distribution panel, then more gas injection flow paths are located near the center of the wafer relative to the periphery of the wafer, resulting in unbalanced engineering gas distribution, thus When forming a plurality of gas injection flow paths 30, it is preferable that the plurality of gas injection flow paths 30 are not axisymmetrically formed with respect to the central axis of the gas distribution panel 40 (see FIG. 3 ).

In addition, the second flow path 32, as shown in the rightmost flow path in FIG. The reflected engineering gas in the second flow path 32 is dispersed to a wider range. Reference symbols D1 and D2 in FIG. 5 indicate the dispersion range of the process gas passing through the second flow path 32 when the inner surfaces of the second flow path are cylindrical and conical, respectively.

Fig. 6 is a partial perspective view showing a lower surface of another gas distribution panel for a chemical vapor apparatus according to the present invention. As shown in Figure 6, the second flow path 32 can be made to have the shape of the extended guide groove 32s. is dispersed over a wider area to distribute the engineering gas evenly to the wafers located on its underside. At this time, the guide groove 32s communicates with at least one or more first flow paths 31 . FIG. 6 shows a situation where three first flow paths 31 share one guide groove 32s.

The length of the extending direction of the guide groove 32s is preferably greater than the length of the vertical direction, that is, the thickness of the guide groove.

In addition, as shown in FIG. 6 , the extension direction of the guide groove 32 s may be formed inclined at a certain angle α with respect to the circumferential direction of the gas distribution panel 40 . The inclination of the guide groove 32s relative to the circumferential direction can also be represented by the fact that the distances between the center 0 of the gas distribution panel 40 and the two ends (p, q) of the guide groove 32s are different from each other. The purpose of forming the guide groove 32s in this way is to distribute and supply the engineering gas sprayed through the guide groove 32s to a certain radial range of the wafer in proportion to the inclination of the guide groove 32s when the wafer support device 20 accommodating the wafer is rotated during the deposition process. effect within.

In this embodiment, the first flow path 31 communicates with the upper space of the gas distribution panel 40 through its inlet 31a, and the second flow path 32 communicates with the lower space of the gas distribution panel 40 through its outlet 32a, but it is not limited to this situation. That is, the first flow path 31 and the second flow path 32 in this embodiment are not only applicable to the situation where a certain flow path is divided into two flow paths. Part of the flow path leads to the change of the flow direction of the engineering gas, so that the velocity component in the vertical direction of the engineering gas is moderated and dispersed in the horizontal direction, which is generally applicable.

If the semiconductor manufacturing process is performed by the chemical vapor deposition apparatus having the improved gas distribution panel as described above, a uniform chemical deposition film can be formed on the wafer and finally a high-quality semiconductor can be manufactured. Specifically, the semiconductor manufacturing method related to the chemical vapor deposition device according to the present invention includes: a gas supply stage, supplying engineering gas to the shower head 50 in the process chamber by a gas supply device (not shown); The engineering gas flows into the gas injection channel 30 through the inlet 31a formed on the upper surface of the gas distribution panel 40; in the dispersion stage, the flow direction of the engineering gas is converted inside the gas injection channel 30, and the velocity component in the vertical direction is weakened to generate The velocity component in the horizontal direction is used to disperse the inflowing process gas; in the injection stage, the dispersed process gas is sprayed to the wafer through the outlet 32 a formed on the lower surface of the gas distribution panel 40 . In particular said dispersion phase is carried out through a flow path formed at an angle relative to the initial flow direction of the engineering gas flowing through the interior of said gas distribution panel.

As described above, the chemical vapor deposition apparatus according to the present invention has an improved gas distribution panel to prevent the process gas from concentrating on the bottom of the center axis of the gas injection flow path of the wafer, so that even the gas distribution panel and the wafer The close distance also enables the engineering gas to be uniformly deposited on the entire surface of the wafer and has the effect of producing high-quality wafers. Therefore, using the chemical vapor deposition apparatus according to the present invention, it is possible to produce high-quality wafers while improving process efficiency, thereby having the effect of improving productivity.

Claims (10)

1. A chemical vapor deposition device comprising a showerhead for distributing engineering gases to wafers inside the process chamber, characterized in that: The shower head includes a gas distribution panel (faceplate) forming a plurality of gas injection flow paths, at least one flow path of the plurality of gas injection flow paths includes a first flow path that starts to flow engineering gas into the gas distribution panel and for changing The second flow path formed by inclining the direction of the engineering gas through the first flow path at a certain angle relative to the direction of the first flow path, the second flow path extends from one end of the first flow path, and the formed The second flow path has non-uniform directionality. 2. The device according to claim 1, characterized in that the range of the angle θ (θ is an acute angle) inclined by the second flow path relative to the direction of the first flow path is as follows: 0°<θ≤45°. 3. The device according to claim 2, wherein the shape of the second flow path has an elongated channel shape. 4. The device according to claim 3, characterized in that the length of the guide groove in the extending direction is greater than the length in the vertical direction. 5. The device according to claim 3, characterized in that the guide groove communicates with at least one first flow path. 6. The device according to claim 3, characterized in that the extending direction of the guide groove is inclined at a certain angle relative to the circumferential direction of the gas distribution panel. 7. The device according to claim 1, wherein the inner surface of the second flow path has a conical shape in which the cross-sectional area of the flow path expands toward the outlet side of the second flow path. 8. The device according to claim 1, wherein the gas injection flow path is formed on the gas distribution panel non-axisymmetrically with respect to the central axis of the gas distribution panel. 9. The apparatus according to claim 6, wherein said process chamber further includes a wafer support device for supporting a wafer, and said wafer support device is configured to be rotatable. 10. The device according to claim 1, wherein the second flow path is formed at an angle relative to the vertical direction, so that the engineering gas passing through the gas distribution panel is dispersed in the horizontal direction and sprayed toward the wafer.

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