Quartz boat device for improving thickness uniformity of deposited film

Abstract

The utility model provides a quartz boat device for improving the thickness uniformity of a deposited film. The quartz boat device comprises a wafer mounting bin and supporting legs. The wafer mounting bin is provided with a wafer support, and the wafer support is used for enabling a plurality of wafers to be arranged in the wafer mounting bin side by side in the axial direction of the wafer mounting bin. The supporting legs are arranged at the bottom of the wafer installation bin, in the height direction, the distance between the circle center of the wafer and the lowest point of each supporting leg is L1, the radius of the wafer is R, and L1-R is larger than or equal to 28 mm and smaller than or equal to 32 mm.

Description

Technical Field

[0001] The present application relates to the field of semiconductor production and manufacturing, and in particular to a quartz boat device for improving the uniformity of deposited film thickness. Background Art

[0002] In the semiconductor industry, thin film deposition is an important process, and low-pressure chemical vapor deposition (LPCVD) is the most common thin film deposition method in the semiconductor industry. In the production process of low-pressure chemical vapor deposition, the uniformity of the deposited film layer is an important indicator for evaluating the quality of the deposited film layer. Good film thickness uniformity has an important impact on each wafer flow link and the final yield of semiconductor products. For a long time, the film thickness uniformity of low-pressure chemical vapor deposition in the industry has not been very ideal. Uneven deposited film layers will seriously affect the subsequent lithography and etching processes, and ultimately affect the electrical performance yield of the product.

[0003] Therefore, how to improve the uniformity of deposited film thickness has become an urgent problem to be solved. Utility Model Content

[0004] The present application provides a quartz boat device for improving the uniformity of deposited film thickness.

[0005] The quartz boat device for improving the uniformity of deposited film thickness provided by the present application comprises:

[0006] A wafer mounting chamber, wherein a wafer support is arranged on the wafer mounting chamber, and the wafer support is used to arrange a plurality of wafers in parallel in the wafer mounting chamber along the axial direction of the wafer mounting chamber;

[0007] The support foot is arranged at the bottom of the wafer mounting chamber. In the height direction, the distance between the center of the wafer and the lowest point of the support foot is L1, the radius of the wafer is R, and it satisfies 28mm≤L1-R≤32mm.

[0008] In at least one embodiment, L1-R=30 mm.

[0009] In at least one embodiment, the wafer holder is used to arrange a plurality of wafers in parallel and vertically in the wafer mounting chamber along the axial direction of the wafer mounting chamber.

[0010] The support feet include a first circumferential support foot and a second circumferential support foot extending along the axial direction, and the first circumferential support foot and the second circumferential support foot are symmetrically arranged at the bottom of the wafer mounting chamber with respect to the axis of the wafer mounting chamber.

[0011] In at least one embodiment, the axial length L2 of the support leg and the axial length L3 of the wafer mounting chamber satisfy: (L3-L2) / L3≤10%.

[0012] In at least one embodiment, the cross-section of the support leg is circular, oval or rectangular.

[0013] In at least one embodiment, the support legs include a first height support leg and a second height support leg stacked in the height direction.

[0014] In at least one embodiment, the first height standoff and the second height standoff are both made of quartz.

[0015] The quartz boat device provided in the present application increases the distance between the wafer and the bottom surface of the furnace paddle by controlling the height of the support legs, thereby improving the uniformity of the deposited film thickness on the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of a quartz boat device according to an embodiment of the present application is shown.

[0017] Figure 2 A side view of a quartz boat device according to one embodiment of the present application is shown.

[0018] Figure 3 A schematic structural diagram of a quartz boat device according to another embodiment of the present application is shown.

[0019] Figure 4 A side view of a quartz boat device according to another embodiment of the present application is shown.

[0020] Figure 5 Schematic diagrams of a quartz boat device before and after modification according to an embodiment of the present application are shown.

[0021] Description of Reference Numerals

[0022] 100 wafer mounting chamber; 110 wafer holder; 200 wafer; 300 legs; 310 first circumferential legs; 320 second circumferential legs; 330 first height legs; 340 second height legs; 350 raised legs; 360 original legs; 400 furnace paddle. DETAILED DESCRIPTION

[0023] The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible methods of the present application, nor to limit the scope of the present application.

[0024] See also Figure 1 , Figure 2 and Figure 5In the thin film deposition process based on low pressure chemical vapor deposition technology, generally, multiple wafers 200 are vertically arranged in the slots of the quartz boat along the axial direction a of the quartz boat, the quartz boat is placed on the furnace paddle 400, and then the furnace paddle 400 is pushed into, for example, a horizontal low pressure chemical vapor deposition furnace tube (not shown in the figure) to perform a deposition reaction. The inventors found that the reaction gas in the furnace tube is unevenly distributed in all directions of the wafer 200, and the film thickness of the end (upper end) of the wafer 200 far from the bottom of the furnace paddle 400 is usually thicker than the film thickness of the end (lower end) close to the bottom of the furnace paddle 400, and the uniformity of the deposited film thickness of the wafer 200 as a whole is poor.

[0025] The inventors also found that by increasing the distance between the wafer 200 and the bottom surface of the paddle 400, the gas flow around the wafer 200 can be smoother and the gas flow distribution can be more uniform, and the uniformity of the deposited film thickness of the wafer 200 can be significantly improved. Based on this discovery, the embodiments of the present application provide a quartz boat device (hereinafter sometimes referred to as a "quartz boat device") for improving the uniformity of deposited film thickness and a manufacturing method thereof.

[0026] See also Figures 1 to 4 , the quartz boat device may include a wafer mounting chamber 100 and a support leg 300. A wafer support 110 may be provided on the wafer mounting chamber 100, and the wafer support 110 is used to allow a plurality of wafers 200 to be arranged in parallel in the wafer mounting chamber along the axial direction a of the wafer mounting chamber 100. Exemplarily, a plurality of wafers 200 are arranged in parallel and vertically on the wafer support 110 along the axial direction a of the wafer mounting chamber 100. The support leg 300 may be provided at the bottom of the wafer mounting chamber 100. The support leg 300 serves as a supporting structure. On the one hand, it is used to stabilize the position of the wafer mounting chamber 100 and prevent it from shaking. On the other hand, it can increase the height of the wafer 200 in the wafer mounting chamber 100, thereby increasing the distance between the wafer 200 and the bottom surface of the furnace paddle 400, so that the gas circulation around the wafer 200 is smoother and the airflow distribution is more uniform, thereby improving the uniformity of the deposited film thickness.

[0027] Among them, the radius of the wafer 200 is R. In the height direction h, when the wafer 200 is set in the wafer installation chamber 100, the distance between the center of the wafer 200 and the lowest point of the support leg 300 is L1, 28mm≤L1-R≤32mm. That is, the quartz boat device provided in the present application controls the spacing between the wafer 200 and the furnace paddle 400 to be 28 to 32mm. More specifically, L1-R can be 28mm, 28.5mm, 29mm, 29.5mm, 30mm, 30.5mm, 31mm, 31.5mm, 32mm, etc.

[0028] In one embodiment of the present application, the quartz boat device is used to mount a 6-inch wafer 200 , and L1 -R is equal to 30 mm.

[0029] In one embodiment of the present application, see Figure 1 and Figure 2 The support legs 300 may include a first circumferential support leg 310 and a second circumferential support leg 320 extending along the axial direction of the wafer mounting chamber 100. The first circumferential support leg 310 and the second circumferential support leg 320 may be symmetrically arranged at the bottom of the wafer mounting chamber 100 about the axis of the wafer mounting chamber 100 to increase stability. The size of the support legs 300 may be controlled to meet the spacing design between the wafer 200 and the paddle 400.

[0030] In one embodiment of the present application, the axial length of the support leg 300 may be substantially the same as the axial length of the wafer mounting chamber 100. Figure 3 The support leg 300 can be integrally formed with the wafer mounting chamber 100. Figure 4 , the axial length L2 of the support leg 300 and the axial length L3 of the wafer mounting chamber 100 can satisfy, (L3-L2) / L3≤10%. It should be understood that the axial length L2 of the support leg 300 can be greater than the axial length L3 of the wafer mounting chamber 100, or less than the axial length L3 of the wafer mounting chamber 100. This formula indicates that the difference in length is within a certain limit to meet the requirement that L2 and L3 are approximately the same.

[0031] In one embodiment of the present application, the cross-section of the support leg 300 may be circular, elliptical or rectangular. It is understood that since the support leg 300 is connected to the wafer mounting chamber 100, a local area of ​​the support leg 300 may be integrated with or matched in shape with the wafer mounting chamber 100, and thus, the circular, elliptical or rectangular shape here may be substantially circular, elliptical or rectangular. For example, Figure 1 , Figure 3 As shown, the cross section of the support leg 300 may be circular. When the cross section is rectangular, the rectangle may be a square.

[0032] In one embodiment of the present application, see Figure 3 and Figure 4 The support foot 300 may include a first height support foot 330 and a second height support foot 340 stacked in a height direction.

[0033] Further, the materials of the first height support 330 and the second height support 340 can be the same, for example, the materials can both be quartz. The dimensions of the first height support 330 and the second height support 340, such as the diameter (or the cross-sectional side length) and the axial length can be the same. Exemplarily, the diameters of the first height support 330 and the second height support 340 can both be 10 mm. Exemplarily, the diameter of the first height support 330 can be 10 mm, and the diameter of the second height support 340 can be 8 to 12 mm.

[0034] Of course, no matter the quartz boat device has one layer of legs 300 , two layers of legs 300 or more layers of legs 300 , as long as the spacing design between the wafer 200 and the paddle 400 can be met.

[0035] The manufacturing method of a quartz boat device for improving the uniformity of deposited film thickness provided in an embodiment of the present application may include: providing a traditional quartz boat device capable of accommodating a wafer 200; setting a raised foot 350 at the bottom of the quartz boat device for contacting a furnace paddle 400; in the height direction, the distance between the center of the wafer 200 and the lowest point of the raised foot 350 is L1, the radius of the wafer 200 is R, and the height of the raised foot 350 is controlled to satisfy: 28mm≤L1-R≤32mm.

[0036] Furthermore, the height of the raised support foot 350 can be controlled to satisfy: L1 - R = 30 mm.

[0037] Further, see Figure 5 , the conventional quartz boat device may include an original support foot 360, and a raised support foot 350 may be provided at the bottom of the original support foot 360. The conventional quartz boat device may already have the original support foot 360, and the raised support foot 350 may be stacked and provided under the original support foot 360 to increase the height of the quartz boat device to meet the spacing design between the wafer 200 and the paddle 400. The original support foot 360 is equivalent to the first height support foot 330, and the raised support foot 350 is equivalent to the second height support foot 340.

[0038] When the cross section of the original support leg 360 is circular, the cross section of the raised support leg 350 may be circular with a groove or rectangular (including rectangular or square) with a groove, etc. The groove may match the outer circumference of the original support leg 360 .

[0039] In one example, the original support leg 360 and the raised support leg 350 may be connected together, and the connection method may be bonding, welding, etc.

[0040] Below, the present application provides a comparative experiment of a conventional quartz boat device and an improved quartz boat device provided by the present application. In the conventional quartz boat device, the distance between the lowest point of the wafer 200 and the lowest point of the support leg 300 is 20 mm. In the quartz boat device provided by the present application, the distance between the lowest point of the wafer 200 and the lowest point of the support leg 300 is 30 mm. The wafer 200 is a 6-inch wafer 200.

[0041] The thin film was deposited by a horizontal low-pressure chemical vapor deposition furnace tube, and the deposition thickness was set to (angstrom), and The film thickness test data of the thin film deposited on the wafer 200 in the conventional quartz boat device and the quartz boat device provided by the present application are collected. The test data include Table 1, Table 2 and Table 3.

[0042] Table 1

[0043]

[0044]

[0045]

[0046] Table 2

[0047]

[0048]

[0049] Table 3

[0050]

[0051]

[0052]

[0053] It can be seen from Table 1, Table 2 and Table 3 that, compared with the traditional quartz boat device, the reaction gas in the improved quartz boat device provided in the embodiment of the present application will circulate more smoothly around the wafer 200 and be more evenly distributed, and the uniformity of the film thickness deposited on the wafer 200 has been significantly improved, for example, an average increase of 1.5%. In the table, the smaller the uniformity value, the more uniform the film thickness. Good film thickness uniformity is of great significance for subsequent photolithography and etching processes, as well as improving the electrical performance yield of the final product.

[0054] It should be understood that a horizontal low-pressure chemical vapor deposition furnace generally has six boat positions, and usually the first boat near the furnace mouth and the sixth boat near the furnace tail are placed with fixed baffles (dummy sheets), and the second to fifth boats are placed with production sheets. Therefore, the present application tests the deposition film thickness of the wafers in the second to fifth boats.

[0055] The above is a preferred embodiment of the present application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A quartz boat device for improving the uniformity of deposited film thickness, characterized in that: include: A wafer mounting chamber, wherein a wafer support is arranged on the wafer mounting chamber, and the wafer support is used to arrange a plurality of wafers in parallel in the wafer mounting chamber along the axial direction of the wafer mounting chamber; The support foot is arranged at the bottom of the wafer mounting chamber. In the height direction, the distance between the center of the wafer and the lowest point of the support foot is L1, the radius of the wafer is R, and it satisfies 28mm≤L1-R≤32mm.

2. The quartz boat device for improving the uniformity of deposited film thickness according to claim 1, characterized in that: L1-R=30mm.

3. The quartz boat device for improving the uniformity of deposited film thickness according to claim 1, characterized in that: The wafer support is used to arrange a plurality of wafers in parallel and vertically in the wafer installation chamber along the axial direction of the wafer installation chamber. The support feet include a first circumferential support foot and a second circumferential support foot extending along the axial direction, and the first circumferential support foot and the second circumferential support foot are symmetrically arranged at the bottom of the wafer mounting chamber with respect to the axis of the wafer mounting chamber.

4. The quartz boat device for improving the uniformity of deposited film thickness according to claim 3, characterized in that: An axial length L2 of the support foot and an axial length L3 of the wafer mounting chamber satisfy (L3-L2) / L3≤10%.

5. The quartz boat device for improving the uniformity of deposited film thickness according to claim 1, characterized in that: The cross section of the supporting foot is circular, oval or rectangular.

6. The quartz boat device for improving the uniformity of deposited film thickness according to claim 1, characterized in that: The support legs include a first height support leg and a second height support leg stacked in the height direction.

7. The quartz boat device for improving the uniformity of deposited film thickness according to claim 6, characterized in that: The first height support and the second height support are both made of quartz.

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