Selective silicon etching solution

An etching solution and selective technology, applied in the field of electronic chemicals, can solve the problems of low selectivity, high etching cost and slow rate of wet etching, and achieve the effects of improving diffusion capacity, maintaining uniformity and reducing mass transfer resistance.

Active Publication Date: 2020-04-17
湖北兴福电子材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention aims at the problems of high cost, slow rate and low wet etching selectivity of silicon etching mechanical grinding and dry etc

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] A selective silicon etching solution is prepared by the following method:

[0031] (1) The mass percentage of each component is: 30% nitric acid, 3% nitrous acid, 40% acetic acid, 8% hydrofluoric acid, 0.15% silicon powder, 0.05% boric acid and the rest water.

[0032] (2) Calculate the mass of each raw material required for the configuration of the etching solution by mass percentage, weigh the ultrapure water of the corresponding quality and place it in a container, slowly add nitric acid, nitrous acid, acetic acid, and hydrofluoric acid into the ultrapure water, wait until After the solution is uniformly mixed, silicon powder and boric acid are added to the solution in turn. After the reaction is complete, the mixture is evenly mixed to obtain selective silicon etching solution 1. The surface tension of the etching solution at 25°C is 41.5mn / m.

[0033] Using selective silicon etchant 1, under the experimental conditions of 25° C. and rotating spray, the undoped sili...

Embodiment 2

[0035] (1) The mass percentage of each component is: 30% ammonium nitrate, 5% nitrous acid, 45% acetic acid, 10% ammonium bifluoride, 0.1% silicon dioxide, 0.15% boron trioxide and the balance of water.

[0036] (2) Calculate the mass of each raw material required for the configuration of the etching solution by mass percentage, weigh the ultrapure water of the corresponding quality and place it in a container, slowly add ammonium nitrate, nitrous acid, acetic acid, and ammonium bifluoride to the ultrapure water, and wait for After the solution is uniformly mixed, silicon dioxide and boron trioxide are added to the solution in turn, and after the reaction is complete, the mixture is uniform to obtain the selective silicon etching solution 2, and the surface tension of the etching solution at 25°C is 38.3mn / m.

[0037] Using selective silicon etchant 1, under the experimental conditions of 25° C. and rotating spray, the undoped silicon was etched for 2 minutes; the p-type silic...

Embodiment 3

[0039] A selective silicon etching solution is prepared by the following method:

[0040] (1) The mass percentage of each component is: 25% sodium nitrate, 4% nitrous acid, 50% acetic acid, 8% ammonium fluoride, 0.1% silicic acid, 0.1% boron trioxide and the balance of water.

[0041] (2) Calculate the mass of each raw material required for the configuration of the etching solution by mass percentage, weigh the ultrapure water of the corresponding quality and place it in a container, slowly add sodium nitrate, nitrous acid, acetic acid, and ammonium fluoride into the ultrapure water, After the solution is mixed evenly, add silicic acid and diboron trioxide to the solution in turn, and mix evenly after the reaction is complete to obtain the selective silicon etching solution 3. The surface tension of the etching solution at 25°C is 35.1mn / m. .

[0042]Using the selective silicon etchant 3 under the experimental conditions of 25° C. and rotary spraying, the undoped substrate s...

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Abstract

The invention belongs to the field of integrated circuit electronic chemicals, and particularly relates to a selective silicon etching solution and a use method thereof. The selective silicon etchingsolution is used for selectively removing undoped silicon on a p-type silicon substrate and comprises nitric acid (or a mixture of nitric acid and a nitrate), nitrite, hydrofluoric acid or a hydrofluoride, a silicon additive, a boron additive and a solvent. According to the etching solution, the nitrate and the nitrite are used for oxidizing silicon into silicon dioxide; etching and removing of silicon dioxide are realized by utilizing hydrofluoric acid; the silicon additive is used for adjusting the etching rate of silicon; the boron additive can inhibit the etching of the p-type silicon by the etching solution, so that the etching solution has a faster etching rate for the undoped silicon than the p-type silicon.

Description

technical field [0001] The invention belongs to the field of electronic chemicals, in particular to a selective silicon etching solution. Background technique [0002] Silicon etching is an important process in the manufacture and packaging of semiconductor integrated circuits. Generally speaking, the manufacturing process of integrated circuits occurs at tens of nanometers to several microns on the surface of the wafer material, and hundreds of processes are performed on the surface of the wafer, including the backside etching of the silicon wafer. After the integrated circuit is manufactured, the integrated circuit needs to be packaged, and before the packaging, the thickness of the silicon wafer needs to be thinned. On the one hand, the heat dissipation effect of the chip can be improved, and on the other hand, the package size can be reduced. Some of the processes require that only undoped silicon be etched to retain the p-type silicon and the integrated circuit structu...

Claims

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Application Information

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IPC IPC(8): C09K13/10
CPCC09K13/10
Inventor 李少平郝晓斌尹印贺兆波张庭万杨阳冯凯王书萍张演哲蔡步林
Owner 湖北兴福电子材料股份有限公司
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