KR20080035735A - Equipment for plasma enhanced chemical vapor deposition - Google Patents

Abstract

PECVD equipment is provided to avoid a failure of a deposition process by forming a silicon oxide layer with a uniform thickness on the front surface of a wafer. A reaction gas supply part supplies a plurality of reaction gases. A reaction chamber supplies a space sealed from the outside to form a predetermined thin film by using the plurality of reaction gases supplied from the reaction gas supply part. A heater table(130) heats a plurality of wafers(170) to a predetermined temperature, supporting the plurality of wafers and installed in the lower part of the reaction chamber. A wafer transfer unit(140) transfers the plurality of wafers supported by the heater table in one direction. A plurality of shower heads(150) have a similar size to the wafer, installed in the upper part of the reaction chamber confronting the heater table and having a structure in which pores for injecting the plurality of reaction gases to the wafer are mixed wherein the pores are made of a hexagonal honeycomb shape(152) and a circular concentric shape(154).

Description

Equipment for plasma enhanced chemical vapor deposition

1 is a plan view schematically showing a plasma chemical vapor deposition apparatus according to the prior art.

FIG. 2 is a cross-sectional view taken along line II to I 'of FIG. 1. FIG.

3 is a perspective view illustrating the shower head of FIG. 1.

Figure 4 is a diagram schematically showing a plasma chemical vapor deposition apparatus according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along line II-II ′ of FIG. 4. FIG.

6 is a perspective view illustrating the showerhead of FIG. 4.

Explanation of symbols on the main parts of the drawings

110: reaction gas supply unit 120: reaction chamber

130: heater table 140: wafer transfer unit

150: shower head 152: honeycomb shape

154: concentric shape 160: plasma electrode

170: wafer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor fabrication equipment, and more particularly to plasma chemical vapor deposition equipment for forming thin films such as silicon oxide films on wafers.

Recently, in the semiconductor manufacturing industry, the minimum line width applied to the semiconductor integrated circuit process has been steadily decreasing to increase the operation speed of the semiconductor chip and increase the information storage capability per unit area. In addition, the size of semiconductor devices such as transistors integrated on semiconductor wafers has been reduced to sub-half microns or less.

Such a semiconductor device may be manufactured through a deposition process, a photo process, an etching process, and a diffusion process, and at least one semiconductor device may be formed when these processes are repeated several times several times. In particular, the deposition process is an essential process requiring improvement in the reproducibility and reliability of semiconductor device fabrication, such as a sol-gel method, a sputtering method, an electroplating method, and an evaporation method. , A process of forming the processed film on the wafer by a chemical vapor deposition method, a molecular beam epitaxy method, an atomic layer deposition method, or the like.

Among them, the chemical vapor deposition method is most commonly used because of the excellent deposition characteristics and the uniformity of the processed film formed on the wafer than other deposition methods. Such chemical vapor deposition methods may be divided into low pressure chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), low temperature chemical vapor deposition (LTCVD), plasma enhanced chemical vapor deposition (PECVD), and the like.

For example, the PECVD is a process of forming a dielectric film by depositing water formed on a wafer by chemical reaction in a gas through an electrical discharge. In the conventional PECVD process, a plurality of wafers are introduced into a plasma chemical vapor deposition apparatus, and a specific film is formed on the plurality of wafers by collectively performing a PECVD process. However, recently, semiconductor devices have been highly integrated and wafers have been integrated. As the large diameter is hardened, a single wafer is introduced into the plasma chemical vapor deposition apparatus, and then a PECVD process is performed. After the PECVD process is performed on the single wafer, the residual gas and the gas present in the plasma chemical vapor deposition apparatus are performed. A washing and purging process is performed to remove the reaction product.

A plasma chemical vapor deposition apparatus for depositing an interlayer insulating film such as a silicon oxide film by such a chemical vapor deposition method is disclosed in US Pat. No. 6,009,827.

Hereinafter, a plasma chemical vapor deposition apparatus according to the prior art will be described with reference to the accompanying drawings.

1 is a plan view schematically showing a plasma chemical vapor deposition apparatus according to the prior art, Figure 2 is a cross-sectional view taken along the line I-I 'of Figure 1, Figure 3 is a perspective view showing the shower head of FIG.

1 to 3, the chemical vapor deposition apparatus according to the prior art, the reaction gas supply unit 10 for supplying a plurality of reaction gases, and the plurality of reactions supplied from the reaction gas supply unit 10 A heater for heating to a predetermined temperature while supporting a plurality of wafers 70 at a lower end of the reaction chamber 20 and the reaction chamber 20 to provide a closed space from the outside so that a predetermined thin film is formed using gas. A plasma electrode 60 formed to excite the reaction gas flowing to the upper portion of the wafer 70 in a plasma state by using a table 30 and a high frequency power applied from the inside of the heater table 30. A wafer transfer unit 40 formed to move the plurality of wafers 70 supported by the heater table 30 in one direction, and the reaction that is opposed to the heater table 30. A plurality of shower heads 50 are formed at an upper end of the chamber 20 and spray the plurality of reaction gases supplied from the reaction gas supply unit 10 to a hexagonal honeycomb 52. .

Here, the reaction gas supply unit 10 generates a plurality of reaction gases to be chemically reacted in the reaction chamber 20 to form the thin film and supplies them to the reaction chamber 20 at a predetermined flow rate. For example, oxygen gas and TEOS gas may be used as the reaction gas. A TEOS gas tank 12 and an oxygen gas tank 14 for storing the oxygen gas and the TEOS gas supplied from the reaction gas supply unit 10, and the TEOS gas tank 12 and the oxygen gas tank 14. The first and second flow control valves (12a, 14b) for controlling the supply flow rate of the oxygen gas and TEOS gas supplied from) and the flow is supplied through the first and second flow control valves (12a, 14a) It includes the first and second flow shut-off valves 112b and 114b which are opened and closed to selectively supply the oxygen gas and the TEOS gas through the supply pipe 16 according to a predetermined condition. In this case, the reaction chamber 20 may accommodate about six wafers 70 so that a silicon oxide film may be sequentially formed on the wafer 70.

In addition, the heater table 30 is formed to heat the wafer 70 to a predetermined temperature in order to stably deposit the silicon oxide film on the wafer 70 in the reaction chamber 20. Although not shown, the heater table 30 includes a plurality of heater blocks formed to individually contact the lower surfaces of the plurality of wafers 70 to heat the wafers 70. The plasma electrode 60 is formed to excite the reaction gas into a high temperature plasma state using the high frequency power to mix the reaction gas in a constant mixing ratio. The wafer transfer unit 40 sequentially rotates the plurality of wafers 70 in the azimuth direction based on the center of the reaction chamber 20 by using the reaction gases injected from the plurality of shower heads 50. The silicon oxide film may be formed.

The shower head 50 is formed to spray the reaction gas supplied from the reaction gas supply unit 10 on the entire surface of the wafer 70. For example, the shower head 50 for injecting the reaction gas in the reaction chamber 20 into which about six wafers 70 are collectively placed may have a hexagonal shape in which the pores formed in the hexagon have a uniform honeycomb shape. Formed. At this time, the shower head 50 formed in the hexagonal honeycomb 52 having a pore is the pressure of the reaction gas discharged from the supply pipe 16 communicated from the reaction gas supply unit 10 in the shower head 50 It is not buffered and is sprayed onto the wafer 70 through the pores. Therefore, a large amount of the reaction gas is injected at the center of the wafer 70 to form a thick silicon oxide film at the center of the wafer 70. In addition, a panel diffuser 56 is formed to primarily block the reaction gas discharged from the end of the supply pipe 16 so that the reaction gas is spread to the edge of the shower head 50. Although the pressure of the reaction gas injected into the pores is lower than the pressure of the reaction gas buffered in the panel diffuser 56, the reaction gas is concentrated at the center of the wafer 70.

As described above, the plasma chemical vapor deposition apparatus according to the prior art has the following problems.

In the conventional plasma chemical vapor deposition apparatus, the reaction gas injected from a plurality of shower heads 50 uniformly formed such that the pores have a hexagonal honeycomb shape 52 is concentrated in the center of the wafer 70 so that the wafer 70 Since the silicon oxide film is formed thicker at the center of the edge than the edge of), it may cause a defect in the deposition process.

An object of the present invention for solving the problems according to the prior art described above is to prevent the reaction gas from flowing intensively in the center of the wafer 70, a silicon oxide film having a uniform thickness on the entire surface of the wafer 70 The present invention provides a plasma chemical vapor deposition method that can increase or maximize production yield by preventing defects in the deposition process.

A plasma chemical vapor deposition apparatus according to an aspect of the present invention for achieving the above object, the reaction gas supply unit for supplying a plurality of reaction gases; A reaction chamber providing a closed space from the outside to form a predetermined thin film using the plurality of reaction gases supplied from the reaction gas supply unit; A heater table configured to heat a predetermined temperature while supporting a plurality of wafers at a lower end of the reaction chamber; A wafer transfer unit formed to move the plurality of wafers supported by the heater table in one direction; And a hexagonal honeycomb and a circular concentric circle each having a hexagon formed in a size similar to that of the wafer at an upper end of the reaction chamber opposite to the heater table, and the holes for injecting the plurality of reaction gases supplied from the reaction gas supply unit into the wafer. It characterized in that it comprises a plurality of shower head having a mixed structure arranged in a shape.

Hereinafter, a plasma chemical vapor deposition apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shape of the elements in the drawings are exaggerated to emphasize a clearer description.

4 is a diagram schematically illustrating a plasma chemical vapor deposition apparatus according to an embodiment of the present invention, FIG. 5 is a cross-sectional view taken along line II-II ′ of FIG. 4, and FIG. 6 is a showerhead of FIG. 150 is a perspective view showing

4 to 6, the plasma chemical vapor deposition apparatus of the present invention, a reaction gas supply unit 110 for supplying a plurality of reaction gases, and the plurality of reactions supplied from the reaction gas supply unit 110 A heater for heating to a predetermined temperature while supporting the plurality of wafers 170 at a lower end of the reaction chamber 120 and the reaction chamber 120 to provide a closed space from the outside to form a predetermined thin film using a gas In the table 130, the plasma electrode 160 formed inside the heater table 130 and configured to excite the reaction gas into a plasma state using a high frequency power applied from the outside, and in the heater table 130 The wafer transfer unit 40 and the heater table 130 are formed so as to move the plurality of supported wafers 170 in one direction in a clockwise or counterclockwise direction. Hexagonal holes are formed at the upper end of the reaction chamber 120 to have the same or similar size as that of the wafer 170 and to inject the plurality of reaction gases supplied from the reaction gas supply unit 110 to the wafer 170. It comprises a plurality of shower head 150 having a structure that is mixed and arranged in a honeycomb shape 152 and a circular concentric shape 154 of the.

Here, the reaction gas supply unit 110 generates a plurality of reaction gases to be chemically reacted in the reaction chamber 120 to form the thin film and supplies them to the reaction chamber 120 at a predetermined flow rate. For example, the reaction gas includes an oxygen gas (eg, a first reaction gas) and a TEOS gas (eg, a second reaction gas). Therefore, the reaction gas supply unit 110 is supplied from the oxygen gas tank 114 and the TEOS gas tank 112 and the oxygen gas tank 114 and the TEOS gas tank 112 to generate and supply the reaction gas. The oxygen gas and TEOS flow-fed through the first and second flow control valves 112a and 114a and the first and second flow control valves 112a and 114a to control a supply flow rate of the oxygen gas and the TEOS gas. And first and second flow shutoff valves 112b and 114b which are opened and closed to selectively supply gas through the supply pipe 116 according to a predetermined condition. Although not shown, a purge gas supply unit supplying a purge gas such as nitrogen gas or argon gas and a cleaning gas supply unit supplying a cleaning gas for cleaning the reaction chamber 120 may be further formed in the reaction chamber 120. It may be.

The reaction chamber 120 is formed on the reaction chamber 120 to form a thin film such as a silicon oxide film on the wafer 170 using oxygen gas and TEOS gas supplied from the reaction gas supply unit 110. It is formed all the time. For example, the reaction chamber 120 may accommodate about six wafers 170 so that a silicon oxide film may be sequentially formed on the wafer 170. Although not shown, the reaction chamber 120 is set to have a predetermined pressure in a vacuum pump for pumping air containing a reaction gas inside the reaction chamber 120 through an exhaust line connected to a lower portion thereof. In addition, at least one vacuum gauge for measuring the vacuum pressure inside the reaction chamber 120 pumped by the vacuum pump is formed.

The heater table 130 is formed to heat the wafer 170 to a predetermined temperature in order to stably deposit the silicon oxide film on the wafer 170 in the reaction chamber 120. For example, the plurality of heater tables 130 are in contact with the lower surface of the wafer 170 to heat the plurality of wafers 170 to a temperature of about 360 ° C to about 390 ° C. The heater table 130 is formed to heat about six wafers 170 at the same or similar time point. In this case, the heater table 130 includes a plurality of heater blocks formed to individually contact the lower surfaces of the plurality of wafers 170 to heat the wafers 170.

The plasma electrode 160 excites the reaction gas into a high temperature plasma state by using the high frequency power to mix the reaction gas at a constant mixing ratio. For example, the plasma electrode 160 may excite the reaction gas into a plasma state using a high frequency power of about 100W to about 200W. Although not shown, the plasma electrode 160 has a lower electrode formed under the heater block at the bottom of the reaction chamber 120 and the showerhead 150 on the top of the reaction chamber 120 facing the heater block. It can be divided into an upper electrode formed on the top. The plasma electrode 160 may excite the reaction gas flowing between the lower electrode and the upper electrode to a plasma state to form a cation that is charged with a positive charge. In this case, when the same or similar high frequency power is applied to the upper electrode and the lower electrode, the reaction gas flows to the upper portion of the wafer 170 by the injection force or gravity of the shower head 150, such as a silicon oxide film. A thin film can be formed. On the other hand, when the high frequency power is concentrated on the lower electrode relative to the upper electrode, the thin film deposited on the wafer 170 may be etched. Although not shown, a matching box for matching the impedance of the high frequency power applied to the plasma electrode 160 is formed outside the reaction chamber 120.

The wafer transfer unit 40 is formed to rotate the plurality of wafers 170 in the azimuth direction with respect to the center of the reaction chamber 120. For example, the wafer transfer unit 40 includes a teaser formed in the shape of a chopstick supporting the lower surface of the wafer 170. In this case, the wafer transfer unit 40 transfers the wafer 170 stepwise so that a plurality of thin films, such as silicon oxide films having a predetermined thickness, may be sequentially formed on the wafer 170 in the plurality of shower heads 150. .

The shower head 150 is formed to spray the reaction gas supplied from the reaction gas supply unit 110 on the entire surface of the wafer 170. In this case, the shower head 150 may be divided into various types for each manufacturer, the pores formed in a hexagonal shape is formed so as to have a honeycomb shape 152 uniformly, or the concentric circle that the pores formed in a circular radius is large at regular intervals. It may be formed to have a shape 154. First, in the case of the EXPRESS facility commercialized by Novellus, the pores for discharging the reaction gas on the wafer 170 are formed in a hexagonal honeycomb shape 152. For example, the silicon oxide film formed by using the shower head 150 having the pores of the hexagonal honeycomb 152 has a tendency that the central portion of the wafer 170 is thicker than the edges. This is because the reaction gas discharged from the end of the supply pipe 116 communicated with the reaction gas supply unit 110 is concentrated not only in the center of the shower head 150 but also flows through the reaction gas. This is because the reaction gas is not passed through the reaction gas to the upper portion of the wafer 170. At this time, the inside of the shower head 150 is first blocked the reaction gas discharged from the end of the supply pipe 116 connected from the reaction gas supply unit 110 to the reaction gas of the shower head 150 A panel diffuser 156 is formed to spread to the edges. However, the panel diffuser 156 is designed to have a certain size because of the difficulty that the size can not be fluidly controlled according to the supply amount of the reaction gas.

On the other hand, in most products commercialized by AMT (Applied Material Technology), the shower head 150 is formed such that the porous holes for discharging the reaction gas have a circular concentric shape 154. The pores are formed to have concentric circles at a predetermined interval from the center of the shower head 150. For example, the silicon oxide film formed by using the shower head 150 having a hole having a circular concentric shape 154 tends to be deposited to have a similar thickness at the center portion and the edge of the wafer 170. In this case, the shower head 150 formed with pores of the circular concentric shape 154 has the reaction gas discharged from the end of the supply pipe 116 communicated from the reaction gas supply unit 110 within the shower head 150. The reaction gas may be uniformly flowed to the upper portion of the wafer 170 because it is formed to be injected at a buffered pressure. In addition, the inside of the shower head 150 by spraying the reaction gas discharged from the end of the supply pipe 116 connected from the reaction gas supply unit 110 primarily wide to the edge of the shower head 150 A spray diffuser 158 is formed to spread out.

Therefore, the plasma chemical vapor deposition apparatus according to the embodiment of the present invention has a shower head 150 having a pore of the hexagonal honeycomb shape 152 of Novellus, and a shower having a pore of a circular concentric shape 154 of AMT The mixture of the head 150 and the inside of the reaction chamber 120 prevents the reaction gas injected through the pores from being concentrated in the center of the wafer 170 and has a uniform thickness on the front surface of the wafer 170. By forming a silicon oxide film having a can prevent the defect of the deposition process can be increased or maximized the production yield.

In addition, the inventive concepts and embodiments disclosed herein may be used by those skilled in the art as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. In addition, such modifications or altered equivalent structures by those skilled in the art may be variously changed, substituted, and changed without departing from the spirit or scope of the invention described in the claims.

As described above, according to the present invention, a showerhead having hexagonal honeycomb-shaped pores of Novellus and a showerhead having circular concentric pores of AMT are mixed and mounted in the reaction chamber to provide the pores. It is possible to prevent the failure of the deposition process by preventing the reaction gas injected through the concentrated flow in the center of the wafer and by forming a silicon oxide film having a uniform thickness on the front surface of the wafer to increase or maximize the production yield It has an effect.

Claims (1)

A reaction gas supply unit supplying a plurality of reaction gases; A reaction chamber providing a closed space from the outside to form a predetermined thin film using the plurality of reaction gases supplied from the reaction gas supply unit; A heater table configured to heat a predetermined temperature while supporting a plurality of wafers at a lower end of the reaction chamber; A wafer transfer unit formed to move the plurality of wafers supported by the heater table in one direction; And Hexagonal honeycomb and circular concentric circles each formed in a size similar to that of the wafer at the upper end of the reaction chamber opposite to the heater table, and the holes for injecting the plurality of reaction gases supplied from the reaction gas supply unit into the wafer, respectively. Plasma chemical vapor deposition facility comprising a plurality of shower heads having a mixed structure formed.

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