Etching liquid

An etching solution and etching technology, applied in the direction of surface etching composition, chemical instruments and methods, electrical components, etc., can solve the problems of etching rate influence, effective utilization of resources and other problems, and achieve small composition changes and low exchange frequency. Effect

Active Publication Date: 2012-03-14
DAIKIN IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] In addition, in the semiconductor manufacturing process, it is known that the wafer is usually etched by immersing it in a chemical solution tank containing buffered hydrofluoric acid. The pure water cleaning tank is brought into the chemical solution tank, and the components of the chemical solution are diluted, so that the composition of the chemical solution changes with time, which has a significant impact on the etching rate
Therefore, the entire chemical solution has to be exchanged over time, and there are problems in terms of processing efficiency and effective use of resources.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～3 and comparative example 1

[0072] Examples 1 to 3 and Comparative Example 1: Evaporation test

[0073] 50% by mass of hydrofluoric acid (A), 40% by mass of ammonium fluoride (B) (containing 0.07% by mass of HF), and the salt (C) obtained from the acids and salts shown in Table 1 were mixed at a predetermined concentration And water (D) to prepare 400 g of etching solution. The HF concentration was adjusted by supplementing the insufficient amount of hydrofluoric acid contained in the added ammonium fluoride (B) with 50% by mass of hydrofluoric acid (A). In addition, among the acids and bases used in the preparation of the salt (C), acetic acid was used at a concentration of 100% by mass, and CH 3 CH 2 NH 2 Use 70% by mass aqueous solution, (CH 3 ) 3 A 25% by mass aqueous solution was used for NOH.

[0074] [Weight measurement of etching solution]

[0075] Store half of the prepared etching solution in a closed container. The remaining half is put into a cylindrical container with a diameter of 8 cm, and th...

Embodiment 4～5

[0088] Examples 4 to 5 and Reference Example 1: Evaporation test

[0089] The NH in the etching solution 4 F concentration is adjusted to 2% by mass, and NH 4 The concentration of F, the type of salt (C), and the amount of salt (C) added were adjusted as shown in Table 3. Except that, the same as Examples 1 to 3 and Comparative Example 1 were carried out to prepare Examples 4 to 5 and Reference Examples 1 of the etching solution. Among them, acetic acid and CH 3 CH 2 NH 2 The same substances as in Examples 1 to 3 and Comparative Example 1 were used, and a 44% by mass aqueous solution of choline was used.

[0090] Table 3 shows the compositions of Examples 4 to 5 and Reference Example 1, and Table 4 shows the results.

[0091] [table 3]

[0092]

[0093] [Table 4]

[0094]

[0095] Even in the NH 4 When the F concentration is adjusted to 2% by mass, the addition of a salt derived from acetic acid and tetramethylammonium hydroxide, and a salt derived from acetic acid and choline can al...

Embodiment 6～7 and comparative example 2

[0096] Examples 6-7 and Comparative Example 2: Water dilution test

[0097] By the same chemical liquid preparation method as shown in the chemical liquid evaporation test, 1000 g of each chemical liquid was prepared, and 200 g of the chemical liquid was prepared by mixing the predetermined amount shown in Table 5 with water, and the etching rate at 25°C was measured.

[0098] [Measurement method of etching rate]

[0099] Adjust the temperature of the etching solution stored in an airtight container to 25°C, and immerse a 1.5cm×1.2cm thermal oxide film (thin film) in each chemical solution for 5 minutes after measuring the initial film thickness, and then wash it off with water After the chemical solution was dried with nitrogen, the thickness of each diaphragm was measured. Then, the difference in film thickness before and after immersion was used as the etching amount, and the etching amount was divided by the etching time as the etching rate.

[0100] Table 5 shows the compositio...

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Abstract

Provided is an etching liquid that contains: hydrofluoric acid (A); ammonium fluoride (B); a salt (C) that comprises an acid (C1) having a higher pKa than hydrofluoric acid (which has a pKa of 3.17) and a base (C2) having higher pKa than ammonium (which has a pKa of 9.24); and water (D). As a result, the liquid chemical does not change much in composition upon evaporation and the like, has a low exchange frequency, and can etch silicon dioxide films with uniformity over time as well.

Description

Technical field [0001] The present invention relates to an etching solution for silicon oxide films used in semiconductor engineering, liquid crystal engineering, etc., a manufacturing method thereof, an etching method using the etching solution, and a manufacturing method of an etching treatment object using the etching solution. Background technique [0002] The wet etching solution of the silicon oxide film uses a mixed solution of hydrofluoric acid and ammonium fluoride solution to buffer hydrofluoric acid (for example, Patent Document 1). In the semiconductor manufacturing process, it is known that the wafer is immersed in a chemical bath containing buffered hydrofluoric acid for etching. However, since the chemical bath usually has an opening for immersing the wafer, the chemical liquid is caused by the evaporation of chemical components. The composition changes over time, which has a major impact on the etching rate. Therefore, all the liquid medicines have to be exchange...

Claims

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Application Information

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IPC IPC(8): H01L21/306H01L21/308
CPCC09K13/08H01L21/31111H01L21/306H01L21/308
Inventor 板野充司中村新吾毛塚健彦江藤友亮
Owner DAIKIN IND LTD
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