TWI764270B - Gas diffuser applicable to chemical vapor deposition - Google Patents

Abstract

A gas diffuser applicable to chemical vapor deposition includes a diffusion disc and a plurality of vents. The diffusion disc includes a first surface and a second surface opposite to the first surface. The first surface is a staircase-like structure elevating from a center thereof to a circumference thereof. The second surface is a planar structure. The plurality of vents extend from the first surface through the second surface. Each vent is in a rectilinear form according to the cross-section thereof and connected to a trumpet opening expanding outwardly. The outwardly expanding trumpet openings are adjacent to the second surface. Thus, a gas can be enclosed in the vents, increasing the gas density and achieving an air curtain effect. Therefore, the velocity of gas flowing through the vents adjacent to the center of the diffusion disc is increased to obtain uniform air coating.

Description

Gas Diffusion Units for Chemical Vapor Deposition

The present invention relates to a gas diffusion device, in particular to a gas diffusion device suitable for chemical vapor deposition.

High temperature chemical vapor deposition (CVD) processes are widely used in the semiconductor industry. The yield and quality of the substrate coating process depend on the deposition uniformity of the substrate film, and the film thickness uniformity is affected by the coating reaction gas dispersed in the reaction chamber. The chemical vapor deposition equipment is equipped with a gas diffusion plate, the gas The diffusion plate is located in the reaction chamber and is used for dispersing the gas flow of the coating reaction gas, so that the coating gas is evenly distributed in the reaction chamber to settle to the substrate to be coated to achieve uniform coating.

Taiwan Invention Patent No. I283437 is a "gas distribution showerhead", which refers to a gas distribution showerhead for semiconductor process, which is characterized by a panel with an elongated groove or channel-type gas outlet. The design of the showerheads relatively close to the wafer increases process airflow near the edge of the wafer, and the edge portion of the panel is less concave relative to the center portion of the panel, however, increased mass flow at the wafer edge may increase The edge thickness of the deposited material results in a thinner film thickness in the middle, which affects the uniformity of the coating. Furthermore, the conventional non-planar structure in which the edge of the gas distribution panel is concave relative to the center of the panel results in poor accuracy and machining difficulties, and needs to be improved.

The above-mentioned disadvantages all present various problems derived from the conventional substrate film. Accordingly, in order to increase the degree of gas distribution in the reaction chamber of the chemical vapor deposition equipment, improve the uniformity of film thickness, and improve the yield and quality of the coating process, the aforementioned conventional The gas diffusion plate does need to be improved.

The purpose of the present invention is to provide a gas diffusion device suitable for chemical vapor deposition, comprising a diffusion plate and a plurality of gas through holes.

The diffuser includes a first surface and a second surface opposite to the first surface, the first surface is a stepped structure gradually rising from the center of the diffuser to the circumference, and the second surface is a In a planar structure, the plurality of gas through holes are arranged through the diffusion plate.

Preferably, the first surface has a first stepped portion, a second stepped portion disposed around the first stepped portion, a third stepped portion disposed around the second stepped portion, and a third stepped portion disposed around the second stepped portion A fourth stepped portion is provided, and a fifth stepped portion is provided around the fourth stepped portion, and the first stepped portion is disposed near the center of the diffuser plate, and the fifth stepped portion is disposed near the circumference of the diffuser plate.

Preferably, the hole-shaped cross-sectional structure of the plurality of gas through holes is a straight hole, and the diameter of the straight hole is 0.1-10 mm.

Preferably, the height difference between adjacent steps is the same.

Preferably, the hole-shaped cross-sectional structure of the plurality of gas through holes is a straight hole connected to an outwardly expanding horn hole, and the outwardly expanding horn hole structure is close to the second surface.

Preferably, the diameter of the straight hole is 0.1-10 mm, and the diameter of the horn hole is 1.5-5 mm.

Preferably, the height of the horn hole is 1~5mm, and the inclination angle of the horn hole expanding outward is 30°~90°.

Preferably, the height difference between the first step and the second step is 1-5mm, the height difference between the second step and the third step is 0.5-3mm, and the third step and the third step are 0.5-3mm. The height difference of the four stepped parts is 0.5-3 mm, and the height difference between the fourth stepped part and the fifth stepped part is 0.5-3 mm.

Preferably, the diameter difference between adjacent stepped portions is the same.

Preferably, the density of the gas through holes on the diffusion plate is 6-10 per square centimeter.

The beneficial effect of the present invention is that the first surface is a stepped structure that gradually rises from the center of the diffuser disk to the circumference, combined with the design of the straight hole connected to the flared hole that expands outward, and the flared hole is located on the same plane On the other hand, the gas frame is surrounded by the plurality of gas through holes, so as to avoid the early diffusion of the gas due to insufficient density during the gas extraction process, and to solve the problem of insufficient gas atmosphere near the center of the diffusion plate, and can slow down the gas The downward flow speed makes it squeeze inward, making up for the problem of slow flow velocity in the middle, increasing the gas density and forming the effect of a gas curtain, thereby increasing the flow velocity of the gas through holes near the center of the diffuser plate, so as to achieve uniform gas coating. effect.

The features and technical contents of the relevant patent applications of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the drawings.

Referring to FIGS. 1 , 2 , and 3 , it is a first preferred embodiment of a gas diffusion device suitable for chemical vapor deposition according to the present invention, which includes a diffusion plate 1 and a plurality of gas through holes 2 . The present invention can be used for wafers of 8 and 12 inches.

The diffuser plate 1 includes a first surface 11 and a second surface 12 opposite to the first surface 11 , the first surface 11 is a stepped structure gradually rising from the center of the diffuser plate 1 to the circumference, and The second surface 12 is a planar structure.

The first surface 11 has a first stepped portion 111, a second stepped portion 112 disposed around the first stepped portion 111, a third stepped portion 113 disposed around the second stepped portion 112, and a second stepped portion 113 disposed around the second stepped portion 112. A fourth stepped portion 114 disposed on the third stepped portion 113, and a fifth stepped portion 115 disposed around the fourth stepped portion 114, and the first stepped portion 111 is disposed close to the center of the diffuser 1, and the fifth stepped portion 111 The stepped portion 115 is disposed close to the circumference of the diffuser disc 1 .

Here, the height difference between the adjacent steps is the same. Further, the height difference d1 between the first ladder part 111 and the second ladder part 112 is 1-5 mm, the height difference d1 between the second ladder part 112 and the third ladder part 113 is 1-5 mm, and the third ladder part 113 is 1-5 mm in height. The height difference d1 between the step portion 113 and the fourth step portion 114 is 1-5 mm, and the height difference d1 between the fourth step portion 114 and the fifth step portion 115 is 1-5 mm.

The plurality of gas through holes 2 are arranged through the diffusion plate 1, and the density of the gas through holes 2 on the diffusion plate 1 is 6 to 10 per square centimeter. Here, the density of the gas through holes 2 is about 32 holes/cm 5.32cm ² . Gas enters from the first surface 11 and flows outward from the second surface 12 . In actual implementation, a shielding plate (not shown) is disposed above the diffusion plate 1 , and a plurality of openings are formed on the shielding plate, and gas flows to the plurality of gas through holes 2 through the openings of the shielding plate.

In the first preferred embodiment, the hole-shaped cross-sectional structure of the plurality of gas through holes 2 is a straight hole 21, and the diameter d2 of the straight hole 21 is 0.1-10 mm. The pitch of the aperture d2 is 3~10mm. The straight hole 21 located on the first stepped portion 111 is the shortest, and the straight hole 21 located on the fifth stepped portion 115 is the longest.

Referring to FIGS. 4 and 5 , it is a second preferred embodiment of the present invention, which is substantially the same as the first preferred embodiment, and the similarities will not be repeated here. The difference lies in the hole patterns of the plurality of gas through holes 2 The cross-sectional structure is that a straight hole 21 is connected to a flared hole 22 , and the flared hole 22 is close to the second surface 12 .

In actual implementation, the horn hole 22 is located on the second surface 12 of the planar structure, which has the effect of simple processing and improved accuracy.

Here, the diameter d2 of the straight hole 21 is 0.1-10 mm, and the diameter d3 of the horn hole 21 is 1.5-5 mm. The height d4 of the horn hole 21 is 1-5 mm, and the inclination angle d5 of the outward expansion of the horn hole 21 is 30°-90°.

The flow velocity of the straight hole 21 on the first stepped portion 111 near the center of the diffuser disc 1 is shorter than that of the straight hole 21 on the fifth stepped portion 115 near the circumference of the diffuser disc 1 , and can be faster reach the substrate to be coated.

Wherein, the height difference d6 between the first ladder part 111 and the second ladder part 112 is 1~5mm, the height difference d6 between the second ladder part 112 and the third ladder part 113 is 0.5~3mm, and the third ladder part 113 is 0.5~3mm. The height difference d6 between the portion 113 and the fourth stepped portion 114 is 0.5-3 mm, and the height difference d6 between the fourth stepped portion 114 and the fifth stepped portion 115 is 0.5-3 mm.

Furthermore, the diameter difference between the adjacent stepped portions is the same. Here, the diameter d7 of the first stepped portion 111 is 60-75 mm, the diameter d7 of the second stepped portion 112 is 100-115 mm, the diameter d7 of the third stepped portion 113 is 140-155 mm, and the fourth stepped portion The diameter d7 of the 114 is 180-195 mm, the diameter d7 of the fifth stepped portion 115 is 220-235 mm, and the diameter difference between the adjacent stepped portions is 40 mm.

Through the first surface 11 is a stepped structure that gradually rises from the center of the diffuser 1 to the circumference, combined with the straight hole 21 to connect the flared hole 22 that expands outward, and the flared hole 22 is located on the same plane. The gas frame is surrounded by the plurality of gas through holes 2 to avoid early diffusion and extraction of gas due to insufficient density during the pumping process, and solve the problem of insufficient gas atmosphere near the center of the diffusion plate 1 . And it can slow down the downward flow speed of the gas and make it squeeze inward, which makes up for the problem of the slow flow rate in the middle, increases the gas density and forms the effect of a gas curtain, thereby increasing the flow rate of the gas through hole 2 near the center of the diffuser disc 1. .

Referring to FIG. 6, it is a cross-sectional flow velocity diagram of the gas diffusion device of the second preferred embodiment. The unit of the numbers in the figure is the gas flow velocity (m/s). It can be known from the gas simulation diagram that through the plurality of gas through holes The hole-shaped cross-sectional structure of 2 is the combination of the straight hole 21 and the horn hole 22, and the gas is evenly distributed, so as to improve the uniformity of the gas coating.

To sum up, the present invention is applicable to a gas diffusion device for chemical vapor deposition. The diffusion plate 1 and the plurality of gas through holes 2 are mutually arranged, and the direction from the center of the diffusion plate 1 through the first surface 11 The stepped structure with a gradually raised circumference is designed in combination with the straight hole 21 to connect the flared hole 22 that expands outward, and the flared hole 22 is located on the same plane, enclosing the gas frame in the plurality of gas through holes 2, and making the The gas density is increased to form a gas curtain, thereby increasing the flow rate of the gas through holes 2 near the center of the diffuser disc 1 to achieve the effect of uniform gas coating, so the object of the present invention can indeed be achieved.

However, the above are only preferred embodiments of the present invention, and should not limit the scope of the present invention, that is, any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the description of the invention, All still fall within the scope of the patent of the present invention.

1: Diffusion disc 11: The first surface 111: The first ladder 112: Second ladder 113: The third ladder 114: Fourth ladder 115: Fifth ladder 12: Second surface 2: Gas through hole 21: Straight hole 22: Horn hole d1: height difference d2: aperture d3: aperture d4: height d5: angle d6: height difference d7: diameter

1 is a schematic perspective view illustrating a first preferred embodiment of a gas diffusion device suitable for chemical vapor deposition according to the present invention; FIG. 2 is a schematic top view illustrating another viewing angle of the first preferred embodiment; Fig. 3 is the A-A sectional view of Fig. 2; 4 is a schematic top view illustrating a second preferred embodiment of the gas diffusion device for chemical vapor deposition according to the present invention; Fig. 5 is the C-C sectional view of Fig. 4; and FIG. 6 is a schematic diagram illustrating the cross-sectional flow velocity distribution of gas in a diffuser plate in the second preferred embodiment.

1: Diffusion disc

111: The first ladder

112: Second ladder

113: The third ladder

114: Fourth ladder

115: Fifth ladder

12: Second surface

2: Gas through hole

21: Straight hole

22: Horn hole

d2: aperture

d3: aperture

d4: height

d5: angle

d6: height difference

Claims (10)

A gas diffusion device suitable for chemical vapor deposition, comprising: A diffuser includes a first surface and a second surface opposite to the first surface, the first surface is a stepped structure gradually rising from the center of the diffuser to the circumference, and the second surface is a planar structure; and A plurality of gas through holes arranged through the diffusion plate. The gas diffusion device suitable for chemical vapor deposition according to claim 1, wherein the first surface has a first stepped portion, a second stepped portion disposed around the first stepped portion, and a second stepped portion surrounding the second stepped portion. A third ladder part arranged on the ladder part, a fourth ladder part arranged around the third ladder part, and a fifth ladder part arranged around the fourth ladder part, and the first ladder part is close to the center of the diffuser plate and the fifth stepped portion is arranged close to the circumference of the diffuser. The gas diffusion device suitable for chemical vapor deposition according to claim 2, wherein the hole-shaped cross-sectional structure of the plurality of gas through holes is a straight hole, and the diameter of the straight hole is 0.1-10 mm. The gas diffusion device suitable for chemical vapor deposition according to claim 3, wherein the height difference between adjacent steps is the same. The gas diffusion device suitable for chemical vapor deposition according to claim 2, wherein the hole-shaped cross-sectional structure of the plurality of gas through holes is a straight hole connected to an outwardly expanding horn hole, and the outwardly expanding horn hole structure near the second surface. The gas diffusion device suitable for chemical vapor deposition according to claim 5, wherein the diameter of the straight hole is 0.1-10 mm, and the diameter of the horn hole is 1.5-5 mm. The gas diffusion device suitable for chemical vapor deposition according to claim 6, wherein the height of the horn hole is 1-5 mm, and the inclination angle of the horn hole expanding outward is 30°-90°. The gas diffusion device suitable for chemical vapor deposition according to claim 7, wherein the height difference between the first stepped portion and the second stepped portion is 1-5 mm, and the second stepped portion and the third stepped portion The height difference is 0.5~3mm, the height difference between the third step and the fourth step is 0.5~3mm, and the height difference between the fourth step and the fifth step is 0.5~3mm. The gas diffusion device suitable for chemical vapor deposition according to claim 8, wherein the diameter difference between adjacent steps is the same. The gas diffusion device suitable for chemical vapor deposition according to claim 1, wherein the density of the gas through holes on the diffusion plate is 6-10 per square centimeter.

Images