JPS62204535A - Manufacture of semiconductor silicon wafer - Google Patents

Abstract

PURPOSE:To eliminate the adherence of dust and an exposure gradation by forming a crystal defect on the back surface of a semiconductor silicon wafer, adhering an amorphous silicon on the back surface having the crystal defect, and mirror-polishing the amorphous silicon to eliminate the uneven back surface of the wafer. CONSTITUTION:A semiconductor silicon wafer 1 is back-damaged to roughen the back surface to form an amorphous silicon 3 of 2-15mum. After the silicon 3 is formed, the polysilicon face of the back surface is mirror-polished. To provide similar effect, polycrystalline silicon, Si3N4 film, SiO2 or other conductor, semiconductor, insulator can be irrespectively used, and similar effect can be expected even in the formation of a multilayer of 2 or more layers of the above material by matching to the formation of an element on the front surface. Since the back surface is mirror-polished so that dusts, contaminants are hardly adhered, dusts adhered or generated in the step or manufacturing an LSI can be reduced by 20-90% to contribute to the improvement in the yield of the LSI proceeded in its miniaturization.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing semiconductor silicon wafers.

[Conventional technology]

Conventionally, the back surface of semiconductor silicon wafers has been roughened by sandblasting, a process known as back damage, which has caused crystal defects. This back damage causes crystal defects on the surface of wafers on which devices are formed, contributing to improved yields of LSIs and ICs.

On the other hand, due to the miniaturization of patterns in recent LSI-related products, dust and dirt are emitted from the backside due to back damage, and exposure blur due to dust on the backside occurs locally during eyelid exposure, resulting in the LSI manufacturing process. It has become an intra-wall area where the yield decreases.

[Problem that the invention seeks to solve]

The conventional technique described above only roughens the back surface by sandblasting or the like to form pack damage.

Because the rough coplanar surface has unevenness, dirt and condensation occur during the manufacturing process.
Dirt easily adhered to the wafer, and the dirt was deposited on the bottom surface of other clean wafers due to wafer handling or other treatments. For this reason, dust adheres to the element forming portion on the bottom surface, causing pattern defects or scratch defects, and a decrease in yield.

Furthermore, if there is dust on the backside during wafer exposure,
For example, when exposing the surface of a rice grain, there is a problem in that the focus is locally deviated by the thickness of the dust, causing an original blur.

[Failure to solve the problem]

An object of the present invention is to eliminate unevenness on the back surface of a semiconductor wafer manufactured by the above-mentioned conventional technique, as well as to eliminate dust adhesion and exposure blur. For this purpose, amorphous noble silicon is formed on the back surface that has been backdamaged, and then mirror polishing is performed to remove the factors that cause dust to adhere.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows a semiconductor silicon wafer 1 in an embodiment of the present invention.
Causes back damage and roughens the surface, 2° then 2μ
A non-forming quality silicon 3 having a thickness of m to 15 μm is formed.

In FIG. 2, after forming amorphous noble silicon 3, the back polysilicon surface is mirror polished.

In this example, amorphous silicon was used on the back side of the silicon wafer, but in order to achieve the same effect, multilayer silicon, i
Mx, N, membrane, 810. It can be used regardless of whether it is a film, a flat body, a semi-coated body, or an insulator, and similar effects can be expected by forming two or more layers of the above-mentioned materials in accordance with the formation of surface elements.

〔Effect of the invention〕

As explained above, the present invention back-damages the back surface of a semiconductor silicon wafer to create crystal defects on the back surface, thereby preventing the occurrence of crystal defects on the surface used as elements such as transistors and diodes, and removing dust and dirt from the back surface. Since the mirror surface is difficult to attract dirt, the amount of dust attached or generated during the LSI manufacturing process can be reduced by 20% to 90%, contributing to an improvement in the yield of LSIs, which are becoming increasingly finer and smaller.

Furthermore, reduction exposure is used for fine patterns, but since it becomes difficult for dust etc. to adhere to the back surface of the silicon wafer, it also has the effect of reducing the out-of-focus during exposure unlike the conventional method.

[Brief explanation of drawings]

l...Silicon wafer, 2...Rough back surface (due to back damage), 3...Amorphous silicon, 4...Amorphous silicon Mirror surface, 5...Silicon wafer, 6...Roughness on the back surface (due to back damage). Kaya 1 M Kaya 211ffi Figure 3

Claims (1)

[Claims] Forming crystal defects on the back surface of a semiconductor silicon wafer and attaching amorphous silicon to the back surface having the crystal defects,
A method for manufacturing a semiconductor silicon wafer, characterized in that the amorphous silicon portion on the back surface is mirror-finished.