Plasma enhanced chemical vapor deposition equipment thin film uniformity improvement device

Abstract

The present invention relates to a device for improving the uniformity of thin films of plasma enhanced chemical vapor deposition equipment. According to the distribution diagram of wafer dielectric thickness obtained by a measuring instrument and the actual situation of growing six-inch and eight-inch wafers by an eight-inch device, a gas-blocking ring is added to the inner groove of an eight-inch gas distribution plate, and a hole is opened in the center of the gas outlet part of the cavity cover, so that the gas is converged to the six-inch wafer area as much as possible, and the gas flow at the edge of the wafer is reduced, thereby improving the uniformity of the thickness of the long film. The present invention avoids the risk of wafer scrapping due to unqualified long film uniformity, and the method can provide a solution for improving the uniformity of thin films of plasma enhanced chemical vapor deposition equipment.

Description

Technical Field

[0001] The invention relates to a device for improving the uniformity of thin films of plasma enhanced chemical vapor deposition equipment, belonging to the technical field of semiconductor manufacturing. Background Art

[0002] Plasma-enhanced chemical vapor deposition equipment is a widely used deposition equipment in the field of semiconductor manufacturing. It uses heating, plasma excitation or light radiation to make gaseous chemicals react and deposit on the surface of the wafer to form a solid film.

[0003] However, currently semiconductor factories have eight-inch machines growing six-inch and eight-inch wafers at the same time. When the six-inch wafers are processed continuously, the uniformity is likely to exceed the specified upper limit, increasing the risk of wafer scrapping due to unqualified film growth uniformity. The chamber needs to be opened and cleaned every two weeks or even once a week, which consumes a lot of time and manpower.

[0004] In view of this, it is necessary to provide a modification device for plasma enhanced chemical vapor deposition equipment to solve the above technical problems. Summary of the invention

[0005] The present invention provides a device for improving the uniformity of thin films of plasma enhanced chemical vapor deposition equipment to solve the technical problems existing in the above-mentioned background technology.

[0006] The technical solution of the present invention: a device for improving the uniformity of thin films of plasma enhanced chemical vapor deposition equipment, the structure of which includes an air blocking ring 1, an air dividing plate 2, an air outlet part 3 and a cavity cover 4, wherein the air dividing plate 2 and the cavity cover 4 are combined to form a cavity, wherein the air dividing plate 2 is an eight-inch air dividing plate, provided with a plurality of air holes, the air blocking ring 1 is annular, placed in the inner groove of the air dividing plate 2, coaxial with the air dividing plate 2, the outer diameter of the air blocking ring 1 is smaller than the groove size, and the inner diameter is larger than the six-inch sheet size; the air outlet part 3 is provided with a through hole in the center, coaxial with the air outlet of the cavity cover 4, and a fan-shaped raised surface is provided on the bottom surface, the air outlet part 3 is placed in the inner groove of the air dividing plate 2, the fan-shaped raised surface coincides with the air outlet plane of the cavity cover 4, and is fixed at the air outlet of the cavity cover by screws.

[0007] The bottom surface of the air outlet part 3 is provided with three sector-shaped raised surfaces, each of which is provided with a long hole for fixing to the cavity cover by screws.

[0008] The outer diameter of the air baffle ring 1 is 200 mm.

[0009] The air baffle ring 1, the air distributor plate 2, the air outlet part 3 and the cavity upper cover 4 are all 2A12 aluminum components.

[0010] Its working method includes the following steps:

[0011] 1) The reaction gas flows out from the gas outlet of the upper cover of the chamber;

[0012] 2) Enter the space formed by the gas distributor and the cavity cover through the gas outlet parts;

[0013] 3) Finally, it passes through the air holes of the air distributor outside the air blocking ring and enters the cavity.

[0014] The beneficial effects of the present invention are as follows: the present invention improves the spatial distribution of the process gas flow by adding air baffle rings and air outlet parts. At the same time, the relatively optimal size design is found through group experimental verification to improve the thin film uniformity of the plasma enhanced chemical vapor deposition equipment. The structure does not require changing the original structure of the machine, greatly reducing the cost of machine modification, and is compatible with six- and eight-inch wafers. The present invention has been verified in practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of explosion and assembly of the air baffle ring of the present invention;

[0016] Figure 2 is an isometric view of the air outlet component of the present invention;

[0017] Figure 3 A cross-sectional view of the present invention when it is working;

[0018] Figure 4 This is a diagram of the dielectric film thickness distribution before the equipment modification in the present invention;

[0019] Figure 5 This is a diagram showing the distribution of dielectric film thickness after the equipment modification in the present invention.

[0020] In the figure, 1 is the air baffle ring, 2 is the air distributor, 3 is the air outlet part, and 4 is the cavity cover. DETAILED DESCRIPTION

[0021] The present invention comprises an air blocking ring placed inside the eight-inch air distribution plate, which has a thickness less than the depth of the groove and an inner diameter slightly larger than the size of the six-inch plate.

[0022] At the center of the inner groove of the gas distribution plate, there is an air outlet part. The three fan-shaped protrusions of the air outlet part are aligned with the upper cover of the equipment and are fixed to the air outlet of the upper cover of the equipment by screws. The center of the air outlet part is punched to increase the air outlet volume at the center of the disc.

[0023] According to the wafer dielectric thickness distribution diagram obtained by the measuring instrument and the actual situation of growing six-inch and eight-inch wafers in eight-inch equipment, the present invention adds a gas-blocking ring in the inner groove of the eight-inch gas distribution plate and opens a hole in the center of the gas outlet part of the cavity cover to try to converge the gas in the six-inch wafer area and reduce the gas flow at the edge of the wafer, thereby improving the uniformity of the film thickness. The risk of wafer scrapping due to unqualified film uniformity is avoided, and this method can provide a solution for improving the uniformity of thin films in plasma-enhanced chemical vapor deposition equipment.

[0024] The technical solution of the present invention is further described below in conjunction with the accompanying drawings

[0025] As attached Figure 1 As shown, the device for improving the uniformity of thin films of plasma enhanced chemical vapor deposition equipment comprises an air baffle ring 1, the outer diameter of which is 200 mm. The air baffle ring 1 is coaxial with the air distributor 2 and is placed in the inner groove of the air distributor 2.

[0026] As attached Figure 2 As shown, the fan-shaped raised surface of the air outlet part 3 coincides with the air outlet plane of the cavity upper cover 4, and a through hole is punched in the center of the air outlet part 3, which is coaxial with the air outlet of the cavity upper cover 4 and is fixed to the cavity upper cover 4 by screws.

[0027] The parts are all made of 2A12 aluminum, which reduces weight while maintaining stable material properties, and will not react with gas to affect process results. After half a year of monitoring of process indicators, the above-mentioned gas distribution plate modification device is effective and the uniformity of the machine is significantly improved.

[0028] As attached Figure 3 As shown, the working process of the present invention is that the reaction gas flows out from the gas outlet of the cavity cover 4, enters the space formed by the gas distributor 2 and the cavity cover 4 through the gas outlet part 3, and finally enters the cavity through the gas holes of the gas distributor outside the air blocking ring 1.

[0029] like Figure 4 As shown, the deposition thickness of the dielectric film before the equipment modification ranged from 43.46nm to 50.98nm, with a standard deviation uniformity of 4.8%. The film thickness was tested using an SE-2000 ellipsometer, with a six-inch wafer having an edge cut of 7mm.

[0030] like Figure 5 As shown, the deposition thickness of the dielectric film after the equipment modification is in the range of 46.44nm-48.91nm, and the standard deviation uniformity is 1.5%. The film thickness test adopts SE-2000 ellipsometer, and the edge of the six-inch disc is cut by 7mm. Compared with the equipment before modification, the uniformity of the dielectric film thickness is greatly improved.

Claims

1. A device for improving thin film uniformity of a plasma enhanced chemical vapor deposition device, characterized in that its structure comprises an air blocking ring (1), an air distribution plate (2), an air outlet part (3) and a cavity upper cover (4), wherein the air distribution plate (2) and the cavity upper cover (4) are combined to form a cavity, wherein: The gas distribution plate (2) is an eight-inch gas distribution plate, provided with a plurality of air holes, the air blocking ring (1) is annular, placed in the inner groove of the gas distribution plate (2), coaxial with the gas distribution plate (2), the outer diameter of the air blocking ring (1) is smaller than the size of the groove, and the inner diameter is larger than the size of the six-inch plate; the center of the gas outlet part (3) is provided with a through hole, coaxial with the gas outlet of the cavity cover (4), and a fan-shaped convex surface is provided on the bottom surface, the gas outlet part (3) is placed in the inner groove of the gas distribution plate (2), the fan-shaped convex surface coincides with the gas outlet plane of the cavity cover (4), and is fixed at the gas outlet of the cavity cover by screws; The bottom surface of the air outlet part (3) is provided with three sector-shaped raised surfaces, each sector-shaped raised surface is provided with a long hole for being fixed to the cavity cover by screws; The outer diameter of the air baffle ring (1) is 200 mm; The air baffle ring (1), the air distributor plate (2), the air outlet part (3) and the cavity upper cover (4) are all 2A12 aluminum components.

2. The operating method of the device for improving thin film uniformity of plasma enhanced chemical vapor deposition equipment as claimed in claim 1, characterized in that The steps include: 1) The reaction gas flows out from the gas outlet of the upper cover of the chamber; 2) Enter the space formed by the gas distributor and the cavity cover through the gas outlet parts; 3) Finally, it passes through the air holes of the air distributor outside the air blocking ring and enters the cavity.

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