CN100490088C

CN100490088C - Method for reducing oxidized silicon chip obverse grain

Info

Publication number: CN100490088C
Application number: CNB2006100306332A
Authority: CN
Inventors: 王明棋
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2006-08-31
Filing date: 2006-08-31
Publication date: 2009-05-20
Anticipated expiration: 2026-08-31
Also published as: CN101136331A

Abstract

This invention discloses a method for reducing particles of positive side of oxide silicon chips, in which, the particles come from the back and surrounding of the last silicon chip and the back of a chip is pre-eroded with hydrofluoric acid of 20-49% concentration so as to reduce particles generated from transferring to the positive of a latter one from the back or side of the last one during the process of erosion of silicon oxide films and increase the quality of products.

Description

Reduce the method for oxidized silicon chip obverse grain

Technical field

The present invention relates to a kind of oxidized silicon chip lithographic method, be meant a kind of method that reduces oxidized silicon chip obverse grain especially.

Background technology

In static random access memory (Static Random Access Memory SRAM) product integrated technique, before growing up, grid oxygen can use a kind of band buffer oxide-film etching liquid (Buffered OxideEnchant BOE, proportioning: HF:NH4F=1.6%:38.7%) preceding engineering is corroded as the sacrificial oxidation silicon chip that injects the barrier layer, corrosion rate is about 190 / minute.This layer oxidized silicon chip is owing to be to use diffusion furnace to grow up, and therefore, all can grow up in the oxidized silicon chip obverse and the back side has one deck silicon oxide film, and thickness is at 100-200

After the corrosion; carry out finding when online blemish is checked; the front of part silicon chip can generate the particle that large tracts of land is scattered; had a strong impact on the yield of product. find by a large amount of experimental analyses; the source of particle comes from last piece of silicon chip back or periphery; because after the operation of oxide-film etching; silicon chip surface exposes large-area silicon substrate zone meeting adsorption particle (the peripheral loop region and the scribe line area of chip); therefore; particles a large amount of when corroding the washing processing in equipment slots can change the surface of rushing down back one piece of silicon chip from last piece of silicon chip back and periphery along flow of liquid, and the silicon chip front can generate a large amount of particles after the processing to be dried.

Therefore, in this technical field, need the method for a kind of effective removal back side and peripheral granule, thus the particle that the silicon chip front of can effectively successively decreasing is produced.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of method that reduces oxidized silicon chip obverse grain, and it can remove the oxidized silicon chip back side and peripheral granule, effectively reduces the oxidized silicon chip corrosion particle generation in silicon chip front afterwards.

For solving the problems of the technologies described above, the method of minimizing oxidized silicon chip obverse grain of the present invention, described oxidized silicon chip is the silicon chip that front and back all has one deck silicon oxide film, wherein, described particle derive from last piece of oxidized silicon chip the back side and around, pre-etching is carried out with hydrofluoric acid in advance in its oxidized silicon chip back side.

Described pre-etching may further comprise the steps: 1) hydrofluoric acid treatment: hydrofluoric acid treatment 2 seconds, 30 ℃ of hydrofluoric acid temperature, 1500 rev/mins of rotary speeies, 2 liters/minute of hydrofluoric acid medicinal liquid flows; 2) washing: deionized water was handled 20 seconds, 500 rev/mins of rotary speeies, 2 liters/minute of de-ionized water flow rate; 3) drying: dry 15 seconds of nitrogen, 2000 rev/mins of rotary speeies, 300 liters/minute of nitrogen flows.

The concentration of described hydrofluoric acid is 20%～49%.

After adopting said method, by in advance in the pre-etching of the oxidized silicon chip back side, removed the particle source that sticks to the oxidized silicon chip back side and periphery effectively, thereby reduce in the silicon oxide film corrosion process in equipment slots the particle of transferring to back one piece of silicon chip surface by last piece of silicon chip back or periphery and producing, improved the qualification rate of product effectively, effectively improved in the defect concentration of static random access memory goods simultaneously in the online detection of grid engineering.

Description of drawings

The present invention is further detailed explanation below in conjunction with accompanying drawing and embodiment.

Fig. 1 is that the false sheet of the present invention inserts the experiment model schematic diagram;

Fig. 2 is the face-to-face experiment model schematic diagram of oxidized silicon chip of the present invention;

Fig. 3 is that the experiment model schematic diagram is handled in pre-etching of the present invention.

Embodiment

The one chip back side rotation etching device (unit type: SP203) that equipment used in the present invention is produced for SEZ company, silicon oxide film is corroded, after the corrosion, when checking, online blemish finds, the front of part silicon chip can generate the particle that large tracts of land is scattered, had a strong impact on the yield of product, at first by experiment the source of analysing particulates.

1. false sheet inserts experiment

Experiment purpose is in order to confirm the coverage of particle, as shown in Figure 1, experiment is provided with two schemes, a kind of is the placement of being separated by of false sheet of mating plate and goods silicon chip, another kind of scheme is a goods silicon chip placed adjacent, found that the silicon chip surface passed examination of being separated by and placing, have only back one piece of silicon chip surface to check defective in the goods silicon chip of placed adjacent.Can obtain thus, goods silicon chip surface particle situation only can be subjected to the influence of last piece of silicon chip when normally placing, can be by self or back one piece or have influence on every a piece silicon chip.Promptly may influence mode be the 1. back side → front, 2. periphery → back one piece of silicon chip front and last piece of silicon chip back

2. goods are tested face-to-face

Experiment purpose is in order to confirm the adhesion mode of particle, and as shown in Figure 2, the first, the second piece of front is relative, and the 3rd piece just facing to second piece the back side, and the 4th piece just facing to the 3rd piece of back side.Found that first piece, second piece and the 4th piece of surface inspection are defective, can obtain thus, particle not only adheres to the front of back one piece of silicon chip from silicon chips periphery or the back side. also can adhere to last piece of silicon chip, but it is can specific adhesion few to the amount of back one piece of silicon chip to adhere to the amount of last piece of silicon chip from silicon chips periphery.

For avoiding the last piece of silicon chip back side and peripheral particle can transfer to the surface of back one piece of silicon chip, in entering the wet method groove, to carry out appending back side soup corrosion treatment before the operation, its processing method is as follows,

The first step: soup is handled: soup was handled 2 seconds, 30 ℃ of fluid temperature, 1500 rev/mins of rotary speeies, 2 liters/minute of medicinal liquid flows;

Second step: washing: deionized water was handled 20 seconds, 500 rev/mins of rotary speeies, 2 liters/minute of de-ionized water flow rate;

The 3rd step: drying: dry 15 seconds of nitrogen, 2000 rev/mins of rotary speeies, 300 liters/minute of nitrogen flows.

Wherein, the soup that uses: concentration is the hydrofluoric acid soup of 20%-49%, temperature 30 degree.

Can obtain thus, the method for removing the sources of particles of the back side and periphery by back side hydrofluoric acid corrosion treatment can thoroughly prevent the positive particle that produces of silicon chip, influences the phenomenon of oxidized silicon chip quality.

Claims

1, a kind of method that reduces oxidized silicon chip obverse grain, described oxidized silicon chip is the silicon chip that front and back all has one deck silicon oxide film, it is characterized in that: the particle of each piece oxidized silicon chip obverse all comes from the back side and the periphery of last piece of oxidized silicon chip, pre-etching is carried out with hydrofluoric acid in advance in each piece oxidized silicon chip back side, and described pre-etching comprises that the hydrofluoric acid soup is handled, washing and dry.

2, the method for minimizing oxidized silicon chip obverse grain as claimed in claim 1 is characterized in that: described pre-etching may further comprise the steps:

1) hydrofluoric acid treatment: hydrofluoric acid treatment 2 seconds, 30 ℃ of hydrofluoric acid temperature, 1500 rev/mins of rotary speeies, 2 liters/minute of hydrofluoric acid medicinal liquid flows;

2) washing: deionized water was handled 20 seconds, 500 rev/mins of rotary speeies, 2 liters/minute of de-ionized water flow rate;

3) drying: dry 15 seconds of nitrogen, 2000 rev/mins of rotary speeies, 300 liters/minute of nitrogen flows.

3, the method for minimizing oxidized silicon chip obverse grain as claimed in claim 1 or 2 is characterized in that: described hydrofluoric acid concentration is 20%～49%.