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Back etching solution and etching method for ultrathin wafer

A backside etching, wafer technology, used in chemical instruments and methods, crystal growth, electrical components, etc., can solve problems such as poor wafer quality, achieve good etching uniformity, and improve the effect of flatness

Active Publication Date: 2021-02-26
SHANGHAI TUNA ELECTRIC MECHANIC EQUIP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the technical problem of poor wafer quality obtained by existing wet etching, and aims to provide a backside etching solution and etching method for ultra-thin wafers

Method used

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  • Back etching solution and etching method for ultrathin wafer
  • Back etching solution and etching method for ultrathin wafer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] Proportion: Take the parts by weight as an example, two parts of the mixed solution made of sulfuric acid, nitric acid and hydrofluoric acid with a mass ratio of 5:2:0.5 are placed in the first etching tank and the second etching tank respectively. in the slot. Wherein, the molar concentration of sulfuric acid is 97%, the molar concentration of nitric acid is 64%, and the molar concentration of hydrofluoric acid is 48%. A hydrofluoric acid solution with a molar concentration of 48% is placed in the hydrofluoric acid tank. Take two parts of hydrochloric acid whose mass percentage content is 0.01% of the mixed solution, and the molar concentration of the hydrochloric acid is 30%.

[0064] Etching method: the wafer is loaded through the loading area; after a portion of hydrochloric acid is dripped into the first etching tank by hand or a metering pump, the wafer is placed in the first etching tank from the loading area, and the wafer The wafer is immersed in the mixed so...

Embodiment 2

[0066] Proportion: Take the parts by weight as an example, two parts of the mixed solution made of sulfuric acid, nitric acid and hydrofluoric acid with a mass ratio of 7:4:1.5 are placed in the first etching tank and the second etching tank respectively. in the slot. Wherein, the molar concentration of sulfuric acid is 98%, the molar concentration of nitric acid is 65%, and the molar concentration of hydrofluoric acid is 49%. A hydrofluoric acid solution with a molar concentration of 49% is placed in the hydrofluoric acid tank. Take two parts of hydrochloric acid whose mass percentage content is 0.05% of the mixed solution, and the molar concentration of hydrochloric acid is 35%.

[0067] Etching method: In addition to etching at 25°C for 60 seconds in the first etching tank, etching at 35°C for 150 seconds in the second etching tank, and staying at 20°C for 20 seconds in the hydrofluoric acid tank , the same as in Example 1 to obtain wafer B.

Embodiment 3

[0069] Proportion: Taking parts by weight as an example, two parts of the mixed solution made of sulfuric acid, nitric acid and hydrofluoric acid with a mass ratio of 6:3:1 are placed in the first etching tank and the second etching tank respectively. in the slot. Wherein, the molar concentration of sulfuric acid is 98%, the molar concentration of nitric acid is 65%, and the molar concentration of hydrofluoric acid is 49%. A hydrofluoric acid solution with a molar concentration of 48.5% is placed in the hydrofluoric acid tank. Take two parts of hydrochloric acid whose mass percentage content is 0.03% of the mixed solution, and the molar concentration of hydrochloric acid is 32%.

[0070] Etching method: In addition to etching at 22°C for 30 seconds in the first etching tank, etching at 35°C for 120 seconds in the second etching tank, and staying at 13°C for 15 seconds in the hydrofluoric acid tank , the same as in Example 1 to obtain wafer C.

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Abstract

The invention belongs to the technical field of semiconductor manufacturing, and particularly relates to a wafer back etching solution and an etching method. The method comprises the steps that: a wafer is loaded through a feeding area; then the wafer is placed in a first etching groove from the feeding area, the wafer is immersed in the mixed solution, and the back face of the wafer is etched; the wafer is placed in a first overflow groove to be cleaned for the first time; then the wafer is placed in a second etching groove for immersing the wafer in the mixed solution and etching the back surface of the wafer again; the wafer is placed in a second overflow groove to be cleaned for the second time; then the wafer is placed in a hydrofluoric acid tank for immersing the wafer in hydrofluoric acid liquid to remove a natural oxide film on the surface; the wafer is placed in a third overflow groove to be cleaned for the third time; and the wafer is blanked through the blanking area, and etching of the wafer is completed. The wafer obtained by adopting the etching liquid and the method is good in surface flatness, good in consistency and relatively good in quality.

Description

technical field [0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a wafer back etching solution and an etching method. Background technique [0002] Etching technique is a technique for selectively etching or stripping the surface of the semiconductor substrate or the surface covering film according to the mask pattern or design requirements in the semiconductor process. Etching technology is not only the basic manufacturing process of semiconductor devices and integrated circuits, but also applied to the processing of thin film circuits, printed circuits and other fine graphics. Etching can be divided into wet etching and dry etching. [0003] Among them, wet etching is the most common etching method with low equipment cost. In wet etching, the factors that affect the etching rate and etching quality usually include etching solution formula, etching temperature and etching time. When the existing etching solu...

Claims

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Application Information

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IPC IPC(8): C30B33/10H01L21/306
CPCC30B33/10H01L21/30604
Inventor 葛林四葛永恒吴士勇韩鹏帅葛威威
Owner SHANGHAI TUNA ELECTRIC MECHANIC EQUIP CO LTD
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