CN102709172A

CN102709172A - Method for corroding silicon wafers in mode of ensuring silicon wafers to be inclined toward reverse sides

Info

Publication number: CN102709172A
Application number: CN2012101792121A
Authority: CN
Inventors: 王亮; 王欢; 王国栋; 李强
Original assignee: Jilin Sino Microelectronics Co Ltd
Current assignee: Jilin Sino Microelectronics Co Ltd
Priority date: 2012-06-01
Filing date: 2012-06-01
Publication date: 2012-10-03

Abstract

The invention relates to a method for corroding silicon wafers in a mode of ensuring the silicon wafers to be inclined toward the reverse sides and belongs to the technical field of manufacturing of a microelectronic chip. In the prior art, the corrosion effect is nonuniform and the within-wafer uniformity and the within-wafer consistency are low. According to the method disclosed by the invention, a plurality of photoetched silicon wafers to be corroded are inserted between basket teeth at both sides inside a wafer bearing basket; then the wafer bearing basket is placed into an etch tank full filled with corrosive liquid; and the corrosive liquid surges up from bottom to top and flows along the surfaces of the silicon wafers and the corrosion chemical reaction is performed on the front sides of the silicon wafers. The method is characterized in that a flow diffusing plate on which through holes are regularly distributed is placed at the bottom of the etch tank and the flow diffusing plate has the gradient of 6 to 10 degrees; the wafer bearing basket is placed on the flow diffusing plate; each silicon wafer is inclined toward the reverse side by 6 to 10 degrees; the reverse sides of the silicon wafers are leaned on the basket teeth; the front sides of the silicon wafers are separated from the basket teeth; and the corrosive liquid has the circular flow of 40 to 50L/min. The method disclosed by the invention is used for carrying out required corrosion on the front sides of the silicon wafers, i.e. the surfaces on which die patterns are engraved, in the production process of a semiconductor device after the photoetching process and before the implanting process.

Description

The silicon chip face tilt caustic solution of supporting or opposing

Technical field

The present invention relates to a kind of silicon chip face tilt caustic solution of supporting or opposing; Can prevent because of the silicon chip front edge with hold sheet basket basket toe joint and touch the halfway phenomenon of the corrosion that causes and take place; Can also improve the corrosion uniformity of silicon chip; Therefore reduce difference and the difference between the same silicon chip different die between the same silicon chip zones of different, thereby improved uniformity and the interior consistency of sheet in the sheet, belonged to microelectronic chip manufacturing technology field.

Background technology

In the semiconductor device production process, after photo-mask process, before the injection process, need corrode the one side that the tube core figure just is carved with in the silicon chip front.This corrosion process carries out in etching tank, and the etching tank material is a safe fluorine dragon (polytetrafluoroethylmaterial material PTFE), and corrosive liquid is by HF, NH ₄The etching aqueous solution that F is made into by different proportion is called for short BOE.Corrosion process is also used a kind of container that holds the sheet basket that is called, and its material also is safe fluorine dragon; The architectural feature of holding the sheet basket is the no end, the basket tooth that inner both sides are vertical, some width that are equally spaced are about 1cm, and adjacent basket space width is greater than silicon wafer thickness.In corrosion process; With treating after several pieces photoetching that corrosion of silicon inserts the basket between cog that holds the inner both sides of sheet basket, between silicon chip, form the gap, will hold the sheet basket afterwards and be placed in the etching tank that fills with corrosive liquid; Corrosive liquid gets into etching tank with the circular flow of 30L/min from the etching tank bottom; Corrosive liquid springs up from bottom to top, flows through along silicon chip surface, at positive corrosion chemical reaction: the SiO that takes place of silicon chip ₂+ 4HF → SiF ₄+ 2H ₂O accomplishes corrosion, in this course, and the SiF that the corrosion chemical reaction produces ₄Gas can be attached to silicon chip surface, thus the blocking-up corrosion reaction, still, SiF ₄Gas can further react with the HF in the corrosive liquid that flows, and generates H ₂SiF ₆Complex compound, that is: SiF ₄+ 2HF → H ₂SiF ₆

Some technical problems below said prior art exists.Corrosive liquid between silicon chip from bottom to top to spring up be to be promoted and produced by the cyclic corrosion liquid that gets into from etching tank bottom, in each silicon chip gap flow and inhomogeneous, corrosive effect is also just inhomogeneous, uniformity is lower with the interior consistency of sheet in the sheet.Have, the circular flow of corrosive liquid 30L/min is not enough so that the SiF that the corrosion chemical reaction produces again ₄Gas breaks away from silicon chip surface all, apace, thereby, also can cause corrosion inhomogeneous.In addition; The buoyancy of corrosive liquid makes silicon chip rock at the basket between cog, and silicon chip front edge and basket be during tooth and contact, and this makes the corrosion rate of the neighboring area that the about 1cm of silicon chip is wide less than zone line; Effective tube core corrosion of neighboring area is not thorough; Finally scrap, effectively the tube core qualification rate reduces, and causes waste of material.

Summary of the invention

Consistency in uniformity and the sheet in the sheet of the corrosion that the objective of the invention is to improve after photo-mask process, the silicon chip front is carried out before the injection process; And overcome the halfway problem of silicon chips periphery zonal corrosion; Improve the effective tube core qualification rate of silicon chip; For this reason, we have invented a kind of silicon chip face tilt caustic solution of supporting or opposing.

The present invention's method treats that corrosion of silicon inserts the basket between cog that holds the inner both sides of sheet basket after with several pieces photoetching; To hold the sheet basket afterwards and be placed in the etching tank that fills with corrosive liquid, corrosive liquid springs up from bottom to top, flows through along silicon chip surface; At the positive corrosion chemical reaction that takes place of silicon chip; It is characterized in that shelve then the distribute diffuser plate of through hole of a slip gauge in etching tank bottom, the diffuser plate gradient is 6 ~ 10 °; Hold the sheet basket and be placed on the diffuser plate, support or oppose 6 ~ 10 ° of face tilts of each silicon chip, the silicon chip back side leans on a basket tooth, and silicon chip is positive to leave with a basket tooth mutually; The circular flow of corrosive liquid is 40 ~ 50L/min.

Its effect of the present invention is that behind the employing diffuser plate, cyclic corrosion liquid is after the etching tank bottom gets into etching tank; Get into again through diffuser plate earlier and hold sheet basket region; Under the effect of the through hole of many regular distribution on the diffuser plate, corrosive liquid springs up in etching tank equably from bottom to top, passes equably the gap between silicon chip; Produce the effect of homogeneous corrosion, improved the interior uniformity of sheet and the interior consistency of sheet of corrosion.The corrosive liquid circular flow rises to 40 ~ 50L/min from existing 30L/min, and the flow velocity of corrosive liquid between silicon chip accelerated.Corrosive liquid and silicon chip surface even contact can either be made like this, SiF can be quickened again ₄Produce H with the HF reaction ₂SiF ₆Complex compound breaks away from silicon chip surface, farthest avoids because of SiF ₄Gas is attached to silicon chip surface blocking-up corrosion reaction and causes corroding inhomogeneous, not thorough.In addition; The face tilt because each silicon chip is supported or opposed, the angle of inclination is enough to make the silicon chip back side to lean on a basket tooth all the time, leave with the basket tooth all the time mutually in the silicon chip front, therefore; No matter be silicon chip zone line or neighboring area; All with corrosive liquid evenly, contact well, corrosion rate is consistent, thereby has eliminated the neighboring area that prior art exists and corrode halfway problem.Round Realization goal of the invention.

Description of drawings

Fig. 1 is the present invention's a method working state schematic representation, and this figure is simultaneously as Figure of abstract.Fig. 2 is the diffuser plate structural representation that the present invention's method adopts.Fig. 3 treats that in the present invention's method the position concerns local enlarged diagram between corrosion of silicon and the basket tooth.

Embodiment

Its embodiment of the present invention's method is following.With treating after several pieces photoetching that corrosion of silicon 1 inserts 3 in the basket tooth that holds sheet basket 2 inner both sides; To hold the sheet basket afterwards and be placed in the etching tank 4 that fills with corrosive liquid, and see shown in Figure 1ly, corrosive liquid springs up from bottom to top; Along silicon chip 1 surface current mistake, at the silicon chip 1 positive corrosion chemical reaction that takes place.Shelve then the distribute diffuser plate 6 of through hole 5 of a slip gauge in etching tank 4 bottoms, see Fig. 1, shown in Figure 2, diffuser plate 6 gradients are 6 ~ 10 °, for example 8 °; Through hole 5 apertures 10 ~ 15mm, 10mm for example, through hole 5 centre-to-centre spacing 20mm; Diffuser plate 6 materials are safe fluorine dragon.Hold sheet basket 2 and be placed on the diffuser plate 6, support or oppose 6 ~ 10 ° of face tilts of each silicon chip 1, for example 8 °; Silicon chip 1 back side leans on basket tooth 3, and leave with a basket tooth 3 mutually in silicon chip 1 front, sees shown in Figure 3; The circular flow of corrosive liquid is 40 ~ 50L/min, for example 50L/min.

Claims

1. silicon chip face tilt caustic solution of supporting or opposing is with treating after several pieces photoetching that corrosion of silicon inserts the basket between cog that holds the inner both sides of sheet basket, will hold the sheet basket afterwards and be placed in the etching tank that fills with corrosive liquid; Corrosive liquid springs up from bottom to top; Flow through along silicon chip surface,, it is characterized in that at the positive corrosion chemical reaction that takes place of silicon chip; Shelve then the distribute diffuser plate of through hole of a slip gauge in etching tank bottom, the diffuser plate gradient is 6 ~ 10 °; Hold the sheet basket and be placed on the diffuser plate, support or oppose 6 ~ 10 ° of face tilts of each silicon chip, the silicon chip back side leans on a basket tooth, and silicon chip is positive to leave with a basket tooth mutually; The circular flow of corrosive liquid is 40 ~ 50L/min.

2. the silicon chip according to claim 1 face tilt caustic solution of supporting or opposing is characterized in that through hole (5) aperture 10 ~ 15mm, through hole (5) centre-to-centre spacing 20mm; Diffuser plate (6) material is safe fluorine dragon.