JPS60260126A - Semiconductor diffusion apparatus - Google Patents

Abstract

PURPOSE:To uniformly diffuse impurity to a semiconductor wafer and make small dispersion of characteristic by comprising a cylindrical furnace core tube having the exhaust tubes at both ends, a plurality of gas injection exhaust ports sorted to the upper and lower sections of furnace core tube and an internal tube from which both ends the gas is supplied. CONSTITUTION:The gas supplied from the gas sending tubes 13, 14 is injected from many gas injection port provided at the upper part of internal tube 12 and is exhausted to the outside of furnace core tube 11 through the exhaust tube 15 from many gas exhaust ports provided to the lower part of internal tube 12. Therefore, the semiconductor wafer 5 is uniformly in the contact with the gas, impurity diffusion to the wafer 5 becomes uniform and dispersion becomes small. Since the wafer 5 is in contact with fresh gas, concentration of impurity in the gas is not different. Moreover, since gas is supplied from both ends, gas injection amount is more equalized. In addition, since the gas is exhausted from many exhaustion ports provided to the lower part of internal tube 12, flow of gas in the internal tube is also more equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semiconductor diffusion device, and more particularly to a diffusion device using a gas as a diffusion impurity source.

(Prior Art) Conventionally, gas is often used as an impurity source to diffuse impurities into semiconductor wafers. FIG. 3 shows a sectional view of essential parts of an example of this conventional diffusion device. The furnace core tube 1 is provided with an air supply pipe 2 at one end, is open to the other end C, and has an exhaust pipe 4 attached to the lid 3, which is covered with a lid 3 at the open end. Semiconductor wafer 5 with lid 3 removed
Insert the boat 6 carrying the and cover it with the lid 3. Gas containing impurities to be diffused is supplied from the air supply pipe 2 as shown by the arrow in the figure, passes through the furnace core tube 1 and is discharged from the exhaust pipe 4.0 While the gas is passing through the furnace core tube 1, it comes into contact with the semiconductor wafer 5. As a result, impurities are diffused into the semiconductor wafer 5.

(Problems to be Solved by the Invention) In such a diffusion device, the impurity concentration in the gas differs between the gas inflow side and the gas outflow side, and the air flow is disturbed by the semiconductor wafer 5, so that the gas and the semiconductor wafer The method of contact with the wafer differs from wafer to wafer, and this has the drawback of causing large variations in the method of impurity diffusion, which causes variations in the characteristics of semiconductor devices. Furthermore, there is a drawback that the number of wafers that can be processed simultaneously is limited because of the need to reduce this variation.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks, and to provide an apparatus for diffusing impurities into semiconductor wafers, which has small variations in impurity diffusion and which can process a large number of semiconductor wafers at the same time.

(Means for Solving the Problems) The semiconductor diffusion device of the present invention has a cylindrical furnace tube having exhaust pipes at both ends, and a plurality of gas jets and discharge ports divided into upper and lower sections in the furnace core tube. It also includes an inner tube to which gas is supplied from both ends.

(Example) Next, embodiments of the present invention will be described using the drawings.

FIG. 1 is a cross-sectional view along the axial direction of an embodiment of the present invention.
FIG. 3 is a sectional view taken along the direction perpendicular to the Ω axis of this embodiment. The furnace core tube 11 is maintained at a constant distance from the inner wall of the furnace core tube 11, and has an inner tube 12 whose space is cut off at an upper part and a lower part.

The inner pipe 12 has a large number of gas jets and discharge ports, and the upper part is connected to gas supply pipes 13 and 14 so that impurity gas can be supplied from both ends. It is connected to a discharge pipe 15 of the furnace core tube and a discharge pipe 17 of the lid 16. Inside the inner tube 12, a large number of semiconductor sea urchins . . . -5 are placed on a boat 6.

With this structure, the gas introduced from the gas supply pipes 13 and 14 is ejected from a number of gas outlets provided at the upper part of the inner pipe 12, and is ejected from a number of gas exhaust ports provided at the lower part of the inner pipe 12. It is discharged to the outside of the furnace core tube 11 via the outlet exhaust pipe 15. Therefore, the gas contacts the semiconductor wafer 5 uniformly, and impurities are uniformly diffused into the wafer 5, reducing variations. Further, since fresh gas comes into contact with each wafer 5, the impurity concentration in the gas does not differ.

Furthermore, since the gas is supplied from both ends, the amount of gas ejected is evenly distributed, and the gas is discharged through a number of outlets provided at the bottom of the inner tube 12, so the flow of gas inside the inner tube is more uniform. be converted into

In this way, since the gas can be made uniform over a wide range within the furnace core tube, the number of wafers that can be processed simultaneously can be increased.

(Effects of the Invention) As described above in detail, according to the present invention, a semiconductor diffusion device can be obtained which can uniformly diffuse impurities into a semiconductor wafer and can further reduce variations in characteristics of manufactured semiconductor elements.

[Brief explanation of drawings]

FIG. 1 is an axial cross-sectional view of an embodiment of the present invention, FIG. 2 is a cross-sectional view perpendicular to the axis of the embodiment of the present invention, and FIG. 3 is a cross-sectional view of essential parts of an example of a conventional semiconductor diffusion device. be. 1... Furnace core tube, 2... Air pipe, 3... Lid, 4...
・Exhaust pipe, 5 semiconductor wafer, 6 boat, 11...
・Furnace core tube, 12・Inner tube, 13・Air pipe, 14・Air pipe, 15・Exhaust pipe, 16・Lid, 17 Exhaust pipe, 18
... spout, 19... discharge port, 20... shielding partition. Rod 2 Men 3 Figure

Claims (1)

[Claims] a cylindrical furnace core tube having exhaust pipes at both ends; an inner tube installed in the cylindrical furnace core tube with a semiconductor substrate installed therein; and an inner tube having openings in the soil wall and the lower wall, respectively; and the cylindrical furnace core. The pipe has a gas inlet and a gas outlet installed in upper and lower sections, and the gas introduced from the gas inlet is introduced into the inner pipe through an opening in the soil wall of the inner pipe, and the gas is introduced into the inner pipe through an opening in the earthen wall of the inner pipe. A semiconductor diffusion device characterized in that the gas discharged from the opening in the lower wall of the tube is discharged to the outside from the gas discharge port.