JPH10256163A - High-speed rotation type single wafer processing vapor growth device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of dust associated with epitaxial growth without removing oxide film from or near the outer periphery of a semiconductor substrate. SOLUTION: Radial grooves 11 are cut into a ring-like semiconductor substrate holder 9 from the placing surface 9A of the holder 9. When the holder 9 is rotated at a high speed, purge gas at the central opening 10 of the holder 9 flows out to the outer peripheral section of the rear surface of a semiconductor substrate through the grooves 11 due to the pumping effect resulting from the high-speed rotation. The flowing-out purge gas blocks the flowing-in of a gaseous starting material to the rear surface of the semiconductor substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed rotation type single wafer type vapor phase growth apparatus, and more particularly to a high-speed rotation type single wafer type vapor phase growth apparatus such as epitaxial growth on a silicon wafer while rotating a silicon wafer mounted on a semiconductor substrate holder at a high speed. The present invention relates to a high-speed rotation type single-wafer-type vapor-phase growth apparatus for performing the following.

[0002]

2. Description of the Related Art The manufacturing process of a silicon semiconductor device includes a number of processes. One of these processes is an epitaxial growth process for forming an epitaxial layer on a silicon wafer. In this epitaxial growth step, a low-concentration epitaxial layer is laminated on a high-concentration silicon substrate, and after forming a silicon oxide film on the back surface of the silicon substrate to suppress autodoping from the silicon substrate, the epitaxial layer is formed. Laminate.

FIG. 7 shows a conventional general high-speed rotary single-wafer type vapor-phase growth apparatus used in an epitaxial growth step. A ring-shaped semiconductor substrate holder 2 is arranged in a vacuum vessel 1. The semiconductor substrate holder 2, on which a silicon semiconductor substrate, that is, a silicon wafer 3, is placed and held. The semiconductor substrate holder 2 is rotated at a high speed while holding the silicon wafer 3. Semiconductor substrate holder 2
A heater 4 is disposed below the heater, and the heater 4 heats the silicon wafer 3. The source gas 5 is supplied to the silicon wafer 3 from above, and epitaxial growth is performed on the silicon wafer 3. Thus, the epitaxial layer 6 is formed on the upper surface of the silicon wafer 3 as shown in FIG.

However, if the silicon oxide film 7 remains on the bevel portion 3a on the back surface of the silicon wafer 3 during the epitaxial growth as shown in FIG. Is formed. Such polysilicon 8 is used as the silicon wafer 3
Is generated by flowing the source gas supplied from above toward the front surface of the silicon wafer 3 into the back bevel portion 3a of the silicon wafer 3. The polysilicon 8 is peeled off in a subsequent process step, which causes a duct.

Therefore, in order to prevent such dust generation, before the epitaxial growth step, the silicon oxide film 7 from the outer periphery of the silicon wafer 3 to about 2 mm is removed by etching as shown in FIG. After the silicon oxide film 7 around the bevel portion 3a is removed in advance in this manner, epitaxial growth is performed to prevent the formation of polysilicon 8 on the back surface of the silicon wafer 3, thereby preventing the polysilicon 8 from being generated. The generation of dust generated can be prevented.

[0006]

However, the above-described method for preventing the generation of polysilicon requires a step of removing a silicon oxide film from around a bevel portion of a silicon wafer.
There is a problem that the process of manufacturing a semiconductor element is complicated.

Further, if the removal amount of the silicon oxide film is too small, polysilicon is generated and dust is generated. On the contrary, if the removal amount is too large, the effect of preventing autodoping, which is the original purpose of the silicon oxide film, is reduced. The resistance of the epitaxial layer near the outer periphery of the silicon wafer is reduced. FIG. 10 is a graph showing the decrease in the resistance value. The resistivity of the epitaxial layer is lower at the outer peripheral portion of the wafer than at the central portion. Therefore, there is a problem that the removal amount of the silicon oxide film must be controlled with very high accuracy.

[0008] The above-mentioned problems also occur in the case of vapor phase growth other than the epitaxial growth of silicon wafers when the source gas flows into the outer peripheral portion of the back surface of the wafer. Therefore, an object of the present invention is to provide a high-speed rotary single-wafer-type vapor-phase growth apparatus that can eliminate the need for performing special treatment on the semiconductor substrate itself and can prevent generation of dust due to vapor-phase growth. That is.

[0009]

In order to achieve this object, the invention according to claim 1 comprises a ring-shaped semiconductor substrate holder having a central opening, and a semiconductor mounted on the semiconductor substrate holder. In a high-speed rotary single-wafer type vapor-phase growth apparatus for performing vapor-phase growth by supplying a source gas from above the substrate, the semiconductor substrate holder is provided with a plurality of radial grooves on its holder mounting surface, The plurality of radial grooves extend so that the gas in the central opening flows out to the outer peripheral portion of the semiconductor substrate through the radial grooves with the rotation of the semiconductor substrate holder. Is what you do.

When the semiconductor substrate holder is rotated, gas flows into the radial groove from the central opening and flows out therethrough to the outer peripheral portion of the semiconductor substrate. The gas flowing out to the outer periphery of the semiconductor substrate prevents the source gas from flowing into the outer periphery of the back surface of the semiconductor substrate. In this way, since the source gas cannot substantially flow on the back surface of the semiconductor substrate, for example, a product such as polysilicon is not generated, and therefore, generation of dust due to the product can be prevented.

According to a second aspect of the present invention, in the high-speed rotary single wafer type vapor phase growth apparatus according to the first aspect, the holder mounting surface is in contact with the lower surface of the semiconductor substrate placed above. And a non-contact area located on the outer peripheral side of the contact area, wherein the plurality of radial grooves are engraved from the central opening to the non-contact portion through the contact area. It is assumed that. Since the radial groove extends from the central opening of the semiconductor substrate holder to the non-contact portion of the holder mounting surface, gas flows through the radial groove to the non-contact portion of the holder mounting surface, and ensures that the outer periphery of the semiconductor substrate Spill into the department.

According to a third aspect of the present invention, in the high-speed rotary single wafer type vapor phase growth apparatus according to the second aspect, the plurality of radial grooves are arranged in a radial direction about a center of the central opening. It is characterized by extending substantially along.

According to a fourth aspect of the present invention, in the high-speed rotary single wafer type vapor phase growth apparatus according to the second aspect, the plurality of radial grooves are formed in a radial direction about the center of the central opening. It is characterized by being inclined with respect to this. As can be seen from the third and fourth aspects of the present invention, the radial grooves can be engraved along the radial direction or can be inclined with respect to the radial direction.

According to a fifth aspect of the present invention, in the high-speed rotary single wafer type vapor phase growth apparatus according to the second aspect, the plurality of radial grooves are engraved on the holder mounting surface at substantially equal intervals. It is characterized by being provided. By forming the radial grooves at equal intervals in this manner, gas flows into the radial grooves from the central opening, passes therethrough, and uniformly flows out to the outer peripheral portion of the semiconductor substrate.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a high-speed rotary single-wafer-type vapor phase growth apparatus according to the present invention will be described below with reference to FIGS. It will be described with reference to FIG.

1 to 3, a semiconductor substrate holder 9 has a ring shape having a central opening 10, and has a holder mounting surface 9A on which the silicon wafer 3 is mounted and a wall thickness larger than the holder mounting surface 9A. And a holder outer peripheral portion 9B defined in the above. As shown in FIG. 2, the holder mounting surface 9 </ b> A has a contact area A where the lower surface of the mounted silicon wafer 3 contacts and a non-contact area B located on the outer peripheral side of the contact part A.

A large number of radial grooves 11 are formed on the holder mounting surface 9A at substantially equal angular intervals. These radial grooves 11 extend radially outward from the center of the holder central opening 10 through the contact area A of the mounting surface 9A to the non-contact area B as clearly shown in FIGS. Are there. Other configurations are the same as those in FIG.

Next, the operation of this embodiment will be described. The silicon wafer 3 is mounted on the holder mounting surface 9A of the semiconductor substrate holder 9 as shown in FIG. By this mounting, the lower surface of the silicon wafer 3 comes into contact with the contact area A of the holder mounting surface 9A, and covers the radial groove 11 located in the contact area A. With this coating, the portion of the coated radial groove 11 becomes a tunnel shape. The silicon wafer 3 has a silicon oxide film 7 formed on the entire back surface.

Thereafter, the semiconductor substrate holder 9 is rotated at a high speed of, for example, about 2000 rpm, and a source gas is supplied from above the silicon wafer 3 to start epitaxial growth. At this time, due to the pump effect accompanying the high-speed rotation of the semiconductor substrate holder 9, the purge gas in the central opening 10 is displaced by the radial grooves 11 as shown by arrows 12 in FIG.
Through the silicon wafer 3 at a high speed.

The raw material gas supplied from above the silicon wafer 3 is greatly reduced from flowing to the back side of the silicon wafer 3 due to the purge gas 12 flowing to the outer peripheral portion of the silicon wafer 3. This prevents the formation of polysilicon on the bevel portion 3a on the back surface of the wafer. In this manner, the production of polysilicon on the back surface of the wafer is prevented without removing the silicon oxide film 7 near the bevel portion 3a on the back surface of the wafer.

In this embodiment, the radial grooves 11 extend almost from end to end of the holder mounting surface 9A in the radial direction. That is, since the radial groove 11 extends from the contact region A to the non-contact region B of the holder mounting surface 9A, the purge gas 12 flows out to the outer peripheral portion of the recon wafer 3 at high speed without fail.

FIG. 4 shows a specific example of the configuration of the radial groove 11. The thickness T of the outer peripheral portion 9B of the semiconductor substrate holder 9 is T = 1.5 mm, and the length S of the mounting surface 9A is S =
0.7 mm, and the thickness t of the mounting surface 9A is t = 0.7 m
m. Radial grooves 11 engraved at equal intervals have a depth D
Is D = 0.3 mm, width W is W = 5 mm, and cycle is 10 mm
It is. The radial groove 11 having such a depth D, width W, and cycle is a preferable example in which the purge gas in the central opening 10 can be discharged at high speed to the entire periphery of the silicon wafer 3. The depth D, width W, period, and the like of the radial groove 11 are not limited to these numerical examples, and can take various values.

FIGS. 5 and 6 show a second embodiment of the present invention, in which a large number of radial grooves 13 engraved on the holder mounting surface 9A at substantially equal angular intervals are provided in the radial direction. It is inclined and extends spirally. Such a spiral groove 13
Also, the gas in the central opening 10 can flow out to the outer peripheral portion of the back surface of the silicon wafer 3. Of course, instead of making the radial grooves 13 inclined with respect to the radial direction curved,
It can also be formed in a straight line.

The first and second embodiments relate to a high-speed rotary single-wafer type vapor-phase growth apparatus for epitaxially growing a silicon wafer placed on a semiconductor substrate holder while rotating the silicon wafer at a high speed. However, the present invention is not limited to epitaxial growth, and can be applied to any vapor phase growth apparatus.

[0025]

As is apparent from the above description, according to the present invention, when the semiconductor substrate holder is rotated, gas flows into the radial groove from the central opening and flows out to the outer peripheral portion of the semiconductor substrate therethrough. However, since the escaping gas prevents the flow of the raw material gas into the back surface of the semiconductor substrate, no product such as polysilicon is generated on the back surface of the semiconductor substrate, and the generation of dust due to the product is prevented. Can be prevented. Therefore, generation of dust due to vapor phase growth can be prevented without performing a process of removing an oxide film or the like from the vicinity of the outer periphery of the semiconductor substrate.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a semiconductor substrate holder which is a main part of a first embodiment of a high-speed rotation type single wafer type vapor phase growth apparatus according to the present invention.

FIG. 2 is a sectional view showing a state where a semiconductor substrate is placed on a semiconductor substrate holder.

FIG. 3 is a line of FIG. 2 showing a part of a semiconductor substrate holder;
Sectional drawing along III-III.

FIG. 4 is an enlarged perspective view showing a semiconductor substrate holder.

FIG. 5 is a perspective view showing a semiconductor substrate holder which is a main part of a second embodiment of the high-speed rotation type single wafer type vapor phase growth apparatus according to the present invention.

FIG. 6 is a plan view showing a semiconductor substrate holder according to a second embodiment.

FIG. 7 is a cross-sectional view showing a conventional general high-speed rotation type single-wafer type vapor phase growth apparatus.

FIG. 8 is a cross-sectional view showing a conventional semiconductor substrate holder and a semiconductor substrate.

FIG. 9 is a sectional view showing a conventional semiconductor substrate holder and a semiconductor substrate.

FIG. 10 is a graph showing the resistivity of an epitaxial layer formed by a conventional high-speed rotation type single wafer type vapor phase epitaxy apparatus.

[Explanation of symbols]

 Reference Signs List 3 semiconductor substrate 5 raw material gas 6 epitaxial layer 9 semiconductor substrate holder 9A holder mounting surface 10 central opening 11 radial groove 12 gas (purge gas flow) 13 radial groove

Claims (5)

[Claims] 1. A high-speed rotary single wafer comprising a ring-shaped semiconductor substrate holder having a central opening, wherein a source gas is supplied from above to a semiconductor substrate mounted on the semiconductor substrate holder to perform vapor phase growth. In the vapor phase epitaxy apparatus, the semiconductor substrate holder has a plurality of radial grooves engraved on the holder mounting surface, and the plurality of radial grooves are formed in the central opening along with the rotation of the semiconductor substrate holder. A high-speed rotary single-wafer type vapor phase growth apparatus, wherein gas extends so as to flow out to the outer peripheral portion of the semiconductor substrate through the radial groove. 2. The plurality of radial grooves, wherein the holder mounting surface has a contact area where the lower surface of the semiconductor substrate placed above contacts, and a non-contact area located on the outer peripheral side of the contact area. 2. The high-speed rotary single-wafer type vapor-phase growth apparatus according to claim 1, wherein a groove is formed from the central opening to the non-contact portion through the contact region. 3. The high-speed rotating single-wafer air according to claim 2, wherein said plurality of radial grooves extend substantially radially around a center of said central opening. Phase growth equipment. 4. The high-speed rotary single-wafer vapor deposition according to claim 2, wherein the plurality of radial grooves are inclined with respect to a radial direction centered on the center of the central opening. apparatus. 5. The high-speed rotary single-wafer vapor deposition apparatus according to claim 2, wherein said plurality of radial grooves are formed at substantially equal intervals on said holder mounting surface.