Sputtering coating blocking device and vacuum sputtering coating machine

Abstract

The invention relates to a sputter coating blocking device and a vacuum sputter coating machine. Comprising a first blocking ring which is located between a wafer and a sputtering target material in the axial direction so as to prevent sputtering ions with the gradient larger than a preset value from being sputtered to the wafer; the second blocking ring surrounds the first blocking ring and is coaxial with the first blocking ring; a first preset distance is arranged between the inner wall of the second blocking ring and the outer wall of the first blocking ring. According to the technical scheme provided by the invention, the problem of poor film thickness uniformity of the coating of the high-aspect-ratio silicon through hole can be solved, and the processing speed is relatively high.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing, and in particular to a sputtering coating blocking device and a vacuum sputtering coating machine. Background Art

[0002] In the evolution of semiconductor manufacturing technology, Moore's Law is basically followed, that is, the size of semiconductors continues to shrink, and the performance of semiconductor devices continues to improve. But at the same time, the interconnection performance continues to deteriorate due to the reduction of line width, making the interconnection line gradually become a bottleneck limiting the improvement of semiconductor chip performance. Therefore, through holes appeared in the semiconductor manufacturing process to better achieve interconnection.

[0003] However, with the diversification of product structures, square through holes with high aspect ratios have emerged, such as aspect ratios greater than 5:1. Conventional sputtering coating solutions will have the problem of poor film thickness uniformity.

[0004] In the prior art, a high temperature deposition process at 400°C to 450°C is usually used to improve the uniformity of film thickness. However, there may be a problem that the top film thickness and the bottom film thickness are not synchronized, or the deposition rate is reduced to improve the synchronization of the two film thicknesses. Summary of the invention

[0005] In view of this, the embodiments of the present application provide a sputtering coating blocking device and a vacuum sputtering coating machine to solve at least one problem existing in the background technology.

[0006] To achieve the above purpose, the technical solution of this application is implemented as follows:

[0007] In a first aspect, an embodiment of the present application provides a sputtering coating blocking device, which is applied to a vacuum sputtering coating machine, wherein the vacuum sputtering coating machine includes a sputtering chamber, a substrate stage, and the sputtering coating blocking device, wherein the substrate stage is used to place a wafer to be coated, and the sputtering coating blocking device includes:

[0008] A first blocking ring is axially located between the wafer and the sputtering target to block sputtering ions with an inclination greater than a preset value from being sputtered onto the wafer;

[0009] The second blocking ring surrounds the first blocking ring and is coaxial with the first blocking ring; the inner wall of the second blocking ring is spaced a first preset distance from the outer wall of the first blocking ring.

[0010] Optionally, the inner diameter of the first barrier ring is 0.3-0.6 times the diameter of the wafer to be plated.

[0011] Optionally, the inner diameter of the second blocking ring is 0.8-0.9 times the diameter of the wafer to be plated.

[0012] Optionally, the first preset distance is 30mm-35mm.

[0013] Optionally, the sputtering coating blocking device further includes:

[0014] The heat dissipation plate surrounds the sputtering chamber and abuts against the inner wall of the sputtering chamber; the heat dissipation plate is provided with at least one first through hole which penetrates axially.

[0015] Optionally, the first through hole is a circular hole.

[0016] Optionally, there are multiple first through holes, which are evenly distributed in the circumference of the first blocking ring.

[0017] In a second aspect, an embodiment of the present application provides a vacuum sputtering coating machine, comprising:

[0018] A sputtering chamber having a vacuum chamber for sputtering operation;

[0019] A substrate stage, used to place the wafer to be plated;

[0020] The sputtering coating blocking device described above.

[0021] Optionally, the vacuum sputtering coating machine further includes:

[0022] The annular heat sink abuts against the outer wall of the heat dissipation plate and is in thermal contact with the side wall of the sputtering chamber.

[0023] Optionally, the sputtering chamber includes an upper end cover and a lower end cover, the upper end cover and the lower end cover together constitute the side wall of the sputtering chamber, the upper end cover and the lower end cover are circular rings with the same outer diameter, and are both in thermal contact with the annular heat sink.

[0024] The sputtering coating blocking device and vacuum sputtering coating machine provided in the embodiment of the present application include: a first blocking ring, located between the wafer and the sputtering target in the axial direction, to block the sputtering ions with an inclination greater than a preset value from being sputtered onto the wafer; a second blocking ring, surrounding the first blocking ring and coaxial with the first blocking ring; the inner diameter of the second blocking ring is set according to the diameter of the wafer to be plated; the outer wall of the second blocking ring is spaced a first preset distance from the inner wall of the first blocking ring; the first blocking ring and the second blocking ring both have a first preset height in the axial direction. It can be seen that the sputtering coating blocking device and vacuum sputtering coating machine of the embodiment of the present application are provided with a first blocking ring and a second blocking ring of different diameters, to block the ions with an inclination greater than a preset value of the sputtering trajectory, that is, to reduce the ions that cannot be injected into the deep groove, and relatively increase the ions with a small inclination of the sputtering trajectory, that is, closer to the vertical direction, that can be injected into the deep groove, which can solve the problem of poor film thickness uniformity in the coating of high aspect ratio silicon through holes, and has a relatively high processing speed. Therefore, the sputtering coating blocking device and the vacuum sputtering coating machine of the embodiments of the present application can solve the problem of poor film thickness uniformity in the coating of high aspect ratio silicon vias, and have a relatively high processing speed.

[0025] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0027] Figure 1 A schematic diagram of a sputtering coating blocking device provided in an embodiment of the present application;

[0028] Figure 2 A schematic top view of a sputtering chamber in a sputtering film blocking device provided in an embodiment of the present application;

[0029] Figure 3 A schematic diagram of a sputtering trajectory in a sputtering coating blocking device provided in an embodiment of the present application;

[0030] Figure 4 It is a schematic diagram of the wafer surface after sputtering coating under electron microscope scanning in the prior art.

[0031] Description of reference numerals:

[0032] 11. Sputtering chamber; 12. Substrate stage; 21. First blocking ring; 22. Second blocking ring; 23. Heat sink; 231. First through hole; 31. First trajectory line; 32. Second trajectory line; 40. Ring heat sink; 51. Upper end cover; 52. Lower end cover; 61. Whisker defect; 70. Target material. DETAILED DESCRIPTION

[0033] In order to make the technical solutions and beneficial effects of the present application more obvious and easy to understand, the following is a detailed description by listing specific embodiments. The drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which the present application belongs.

[0034] In the description of the present application, terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of simplified description of the present application, and do not indicate that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation on the present application.

[0035] In this application, the terms "first" and "second" are used only for the purpose of clear description and should not be understood as the relative importance of the indicated features or the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly include at least one of the features. In the description of this application, "multiple" means at least two, such as two, three, etc.; "several" means at least one, such as one, two, three, etc., unless otherwise clearly and specifically defined.

[0036] In this application, unless otherwise clearly defined, the terms "install", "connect", "connect", "fix", "set", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] In the present application, unless otherwise clearly defined, a first feature being “on”, “above”, “above”, “below”, “below”, “below” or “below” a second feature may mean that the first feature is in direct contact with the second feature, or the first feature and the second feature are in indirect contact with each other through an intermediate medium. Moreover, a first feature being “on”, “above” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than the horizontal height of the second feature. A first feature being “below”, “below” or “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than the horizontal height of the second feature.

[0038] In order to thoroughly understand the present application, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0039] The inventors of the present application discovered during research and development that for silicon vias with high aspect ratios, there is a problem of poor uniformity in film thickness, such as the top and bottom film thicknesses being out of sync. The main reason is that ions whose sputtering trajectory has an inclination greater than a preset value cannot be injected into the bottom of the silicon via with a high aspect ratio, but are instead injected into the surface outside the silicon via, causing the film thickness on the surface outside the silicon via to be much thicker than that inside the silicon via. Although high-temperature deposition can help increase the mobility of metal ions and improve some uniformity problems, the improvement is not large, and this improvement is obtained under the premise of reducing the sputtering power and lowering the coating speed, which increases production costs.

[0040] Therefore, after further research and development, the inventor proposed the following technical solution.

[0041] The present application embodiment provides a sputtering coating blocking device, which is applied to a vacuum sputtering coating machine, referring to Figure 1 and Figure 2 The vacuum sputtering coating machine comprises a sputtering chamber 11, a substrate stage 12 and the sputtering coating blocking device, wherein the substrate stage 12 is used to place the wafer to be coated; Figure 1-Figure 3 , the sputtering coating blocking device comprises:

[0042] The first blocking ring 21 is axially located between the wafer and the sputtering target 70 to block the sputtering ions with an inclination greater than a preset value from being sputtered onto the wafer;

[0043] The second blocking ring 22 surrounds the first blocking ring 21 and is coaxial with the first blocking ring 21 ; an inner wall of the second blocking ring 22 and an outer wall of the first blocking ring 21 are spaced a first preset distance apart.

[0044] It can be understood that the hole of the high aspect ratio silicon via is relatively deep, so the trajectory lines of the ions that can be injected into the high aspect ratio silicon via are close to the vertical angle, that is, the inclination of the trajectory line is small. On the contrary, the inclination of the trajectory line is large. Therefore, it can be known that the number of ions that can be injected is much smaller than the number of ions that cannot be injected. Therefore, it is necessary to try to reduce the number of ions that cannot be injected into the wafer surface outside the high aspect ratio silicon via.

[0045] Specifically, see Figure 3 , the direction emitted from the target 70 to the wafer in the figure is the sputtering trajectory of the ions. Among them, the top one is called the first trajectory line 31, and there are multiple ions below, collectively referred to as the second trajectory line 32. Under the blocking of the first blocking ring 21, in addition to the ions of the first trajectory line 31 and the second trajectory line 32 shown in the figure can be shot to the wafer, the ions between the first trajectory line 31 and the second trajectory line 32 are blocked by the blocking ring and cannot be shot to the wafer, reducing the number of ions shot into the surface outside the high aspect ratio silicon through hole and reducing the problem of uneven film thickness.

[0046] Without limitation, the trajectory line between the first trajectory line 31 and the second trajectory line 32 (including the first trajectory line 31 and the second trajectory line 32) can be considered as a situation where the inclination is greater than the preset value. It can be understood that the inclination greater than the first trajectory line belongs to the situation where the inclination is greater than the preset value, and the probability of blocking is greater. It can also be understood that the inclination is less than the second trajectory line and it will be blocked, but the probability will be reduced until the inclination is less than or equal to the preset value, and it will not be blocked. And these ions that will not be blocked can basically be injected into high aspect ratio silicon vias. Therefore, the preset value of the inclination is related to whether it can be injected into high aspect ratio silicon vias.

[0047] It is understandable that there are many points on the target 70 that are bombarded and produce ion emission, and the figure only shows a few of them. In addition, there are many sputtering trajectories of ions generated by the bombardment point of the same target 70, and the figure only shows a few of the trajectory lines.

[0048] The purpose of setting two blocking rings is to better cover the entire area of ​​the wafer, wherein the first blocking ring 21 mainly blocks ions injected into the central area of ​​the wafer, and the second blocking ring 22 mainly blocks ions injected into the edge area of ​​the wafer. Therefore, the two blocking rings need to be spaced by a first preset distance so as to be staggered radially to better block ions in various areas.

[0049] It is understandable that the inner diameter of the second blocking ring 22 can be set according to the diameter of the wafer to be plated. That is, the second blocking ring 22 mainly blocks ions injected into the edge area of ​​the wafer, so the inner diameter is only slightly smaller than the diameter of the wafer to be plated.

[0050] It is understandable that more blocking rings may be provided, which may achieve better results, but the marginal effect is reduced and the cost is relatively high.

[0051] It is understandable that the blocking ring cannot block too many other ions except for the ions with large incident angles in the sputtering trajectory. Therefore, the wall thickness of the blocking ring in the radial direction needs to be as thin as possible while being strong enough. Specifically, the wall thickness can be 3mm-5mm.

[0052] It can be understood that the first blocking ring 21 and the second blocking ring 22 have a certain height in the axial direction to block the ions with large incident angles in the sputtering trajectory. Specifically, the height can be 20mm-40mm.

[0053] The sputtering coating blocking device of the embodiment of the present application is provided with a first blocking ring 21 and a second blocking ring 22 of different diameters to block ions whose sputtering trajectory has an inclination greater than a preset value, i.e., reduce ions that cannot be shot into the deep groove, and relatively increase ions whose sputtering trajectory has a small inclination, i.e., closer to the vertical direction, that can be shot into the deep groove. This can solve the problem of poor film thickness uniformity in the coating of silicon vias with a high aspect ratio and has a relatively high processing speed.

[0054] Specifically, the target material 70 for sputtering coating in this embodiment can be aluminum. Aluminum has excellent comprehensive properties and is widely used in low-resistance ohmic contacts and internal interconnects. In addition, using sputtering or evaporation to prepare aluminum film can obtain a film layer structure with good uniformity, good contact, and relatively stable, thereby improving product reliability.

[0055] Specifically, the coating speed before the improvement may be 0.62 pieces / hour, and the coating speed after the improvement may be 2.3 pieces / hour.

[0056] In some other embodiments of the present application, the inner diameter of the first barrier ring 21 is 0.3-0.6 times the diameter of the wafer to be plated.

[0057] In this way, ions that should fall on the center area of ​​the wafer can be blocked, reducing the problem of uneven film thickness inside and outside the high aspect ratio silicon via here.

[0058] In some other embodiments of the present application, the inner diameter of the second blocking ring 22 is 0.8-0.9 times the diameter of the wafer to be plated.

[0059] In this way, ions that should fall on the outer edge area of ​​the wafer can be blocked, thereby reducing the problem of uneven film thickness inside and outside the high aspect ratio silicon through hole here.

[0060] In some other embodiments of the present application, the first preset distance is 30mm-35mm.

[0061] In this way, there is enough space between the two rings to correspond to the central area and the edge area respectively, so as not to interfere with each other and cause an imbalance in the number of ions injected into the two areas.

[0062] In some other embodiments of the present application, the sputtering coating blocking device further includes:

[0063] The heat dissipation plate 23 surrounds the sputtering chamber 11 and abuts against the inner wall of the sputtering chamber 11 . The heat dissipation plate 23 is provided with at least one first through hole 231 extending axially therethrough.

[0064] The heat dissipation plate 23 abuts against the inner wall of the sputtering chamber 11 , which can better conduct the heat to the sputtering chamber 11 and dissipate the heat quickly.

[0065] Furthermore, the first through hole 231 can be connected to a cold source, such as a coolant, to dissipate heat more quickly.

[0066] There may be one or more first through holes 231. When there is one first through hole 231, the first through hole 231 may be an annular hole surrounding the first barrier ring 21 so that the ions passing therethrough are uniform in the circumferential direction.

[0067] It can be understood that the heat dissipation plate 23 has a preset wall thickness. In this way, the heat dissipation effect can be better exerted, and a larger radial area is provided for opening the axial first through hole 231. Specifically, the preset wall thickness can be 15 mm-25 mm.

[0068] In some other embodiments of the present application, the first through hole 231 is a circular hole, which is conducive to high-speed passage of ions and is more convenient to process.

[0069] In some other embodiments of the present application, there are multiple first through holes 231 , which are evenly distributed in the circumference of the heat dissipation plate 23 .

[0070] In this way, the heat dissipation can be more uniform and the heat dissipation effect can be better.

[0071] The present application also provides a vacuum sputtering coating machine, comprising:

[0072] The sputtering chamber 11 has a vacuum chamber for sputtering operation;

[0073] A substrate stage 12 is used to place the wafer to be plated;

[0074] The sputtering coating blocking device described above.

[0075] That is, the sputtering chamber 11 has a preset vacuum degree so that the ions will not be contaminated during operation, and the sputtering trajectory and sputtering speed of the ions will not be affected by the air.

[0076] The vacuum sputtering coating machine of the embodiment of the present application is provided with a first blocking ring 21 and a second blocking ring 22 of different diameters to block ions whose sputtering trajectory has an inclination greater than a preset value, i.e., reduce ions that cannot be injected into the deep groove, and relatively increase ions whose sputtering trajectory has a small inclination, i.e., closer to the vertical direction, that can be injected into the deep groove. This can solve the problem of poor film thickness uniformity in the coating of silicon vias with a high aspect ratio and has a relatively high processing speed.

[0077] In some other embodiments of the present application, the vacuum sputtering coating machine further includes:

[0078] The annular heat sink 40 abuts against the outer wall of the heat sink 23 and is in thermal contact with the side wall of the sputtering chamber 11 .

[0079] In this way, the accumulated temperature of the vacuum chamber can be reduced, that is, the accumulated temperature due to continuous operation in the vacuum chamber can be reduced. Reduce whisker defects on the film surface caused by high temperature 61, see Figure 4 After the improvement, the whisker defect is no longer visible due to the improvement of heat dissipation 61.

[0080] In other embodiments of the present application, the sputtering chamber 11 includes an upper end cover 51 and a lower end cover 52, and the upper end cover 51 and the lower end cover 52 together constitute the side wall of the sputtering chamber 11, and the upper end cover 51 and the lower end cover 52 are circular rings with the same outer diameter, and both are in thermal contact with the annular heat sink 40.

[0081] In this way, the sputtering chamber 11 can dissipate heat more evenly.

[0082] Specifically, the upper half end cover 51 and the lower half end cover 52 are both made of SUS316 stainless steel, which has good thermal conductivity.

[0083] It should be understood that the above embodiments are exemplary and are not intended to include all possible implementations included in the claims. Various modifications and changes may be made on the basis of the above embodiments without departing from the scope of the present disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form other embodiments of the present application that may not be explicitly described. Therefore, the above embodiments only express several implementations of the present application and do not limit the scope of protection of the patent of this application.

Claims

1. A sputtering coating blocking device, applied to a vacuum sputtering coating machine, the vacuum sputtering coating machine comprising a sputtering chamber, a substrate stage and the sputtering coating blocking device, the substrate stage being used to place a wafer to be coated, characterized in that: The sputtering coating blocking device comprises: A first blocking ring is axially located between the wafer and the sputtering target to block sputtering ions with an inclination greater than a preset value from being sputtered onto the wafer; The second blocking ring surrounds the first blocking ring and is coaxial with the first blocking ring; the inner wall of the second blocking ring is spaced a first preset distance from the outer wall of the first blocking ring.

2. The sputtering coating blocking device according to claim 1, characterized in that: The inner diameter of the first barrier ring is 0.3-0.6 times the diameter of the wafer to be plated.

3. The sputtering coating blocking device according to claim 1, characterized in that: The inner diameter of the second blocking ring is 0.8-0.9 times the diameter of the wafer to be plated.

4. The sputtering coating blocking device according to claim 1, characterized in that: The first preset distance is 30mm-35mm.

5. The sputtering coating blocking device according to claim 1, characterized in that: The sputtering coating blocking device also includes: The heat dissipation plate surrounds the sputtering chamber and abuts against the inner wall of the sputtering chamber; the heat dissipation plate is provided with at least one first through hole which penetrates axially.

6. The sputtering film blocking device according to any one of claim 5, characterized in that: The first through hole is a circular hole.

7. The sputtering coating blocking device according to claim 6, characterized in that: There are a plurality of first through holes, which are evenly distributed in the circumference of the heat sink.

8. A vacuum sputtering coating machine, characterized in that: include: A sputtering chamber having a vacuum chamber for sputtering operation; A substrate stage, used to place the wafer to be plated; The sputtering coating blocking device according to any one of claims 1 to 7.

9. The vacuum sputtering coating machine according to claim 8, characterized in that: The vacuum sputtering coating machine also includes: The annular heat sink abuts against the outer wall of the heat dissipation plate of the sputtering coating blocking device and is in thermal contact with the side wall of the sputtering chamber.

10. The vacuum sputtering coating machine according to claim 9, characterized in that: The sputtering chamber comprises an upper end cover and a lower end cover, which together constitute the side wall of the sputtering chamber. The upper end cover and the lower end cover are circular rings with the same outer diameter and are both in thermal contact with the annular heat sink.

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