US-20260130146-A1 - SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING APPARATUS

Abstract

A substrate processing method includes generating an etching liquid by adding a silicic acid compound to an alkaline processing liquid, and etching a polysilicon film formed on a substrate with the etching liquid.

Inventors

• Reiko Abe
• Yuta HAMASHIMA

Assignees

• TOKYO ELECTRON LIMITED

Dates

Publication Date

20260507

Application Date

20251104

Priority Date

20241105

Claims (20)

1. 1 . A substrate processing method, comprising: generating an etching liquid by adding a silicic acid compound to an alkaline processing liquid; and etching a polysilicon film formed on a substrate with the etching liquid.
2. 2 . The substrate processing method of claim 1 , wherein the polysilicon film is provided on an inner surface of a recess formed in a surface of the substrate, and the etching of the polysilicon film includes etching at least a portion of the polysilicon film provided on the inner surface of the recess.
3. 3 . The substrate processing method of claim 1 , wherein a concentration of silicic acid in the alkaline processing liquid is between 80 ppm and 160 ppm.
4. 4 . The substrate processing method of claim 1 , wherein the silicic acid compound is colloidal silica.
5. 5 . The substrate processing method of claim 1 , wherein the silicic acid compound is at least one of sodium silicate, potassium silicate, or calcium silicate.
6. 6 . The substrate processing method of claim 1 , wherein the processing liquid is diluted aqueous ammonia, SC1 (a mixture of aqueous ammonia and aqueous hydrogen peroxide), NC2 (a mixture of an aqueous solution of choline and an aqueous hydrogen peroxide), or TMAH (tetramethylammonium hydroxide).
7. 7 . The substrate processing method of claim 1 , wherein a temperature of the etching liquid when performing the etching processing of the lot is in a range of 40° C. to 80° C.
8. 8 . A substrate processing apparatus, comprising: a processing tub in which an etching processing is performed by immersing a lot, which includes one or more substrates, in an etching liquid prepared by adding a silicic acid compound to an alkaline processing liquid; a processing liquid supply configured to supply the processing liquid to the processing tub; a silicic acid supply configured to supply the silicic acid compound to the processing tub; a concentration measurement circuit configured to measure a concentration of a component of the etching liquid stored in the processing tub; controller circuitry configured to control individual components; and a storage circuit configured to store correlation data representing a correlation between a concentration of the silicic acid compound in the etching liquid in the processing tub and an etching rate of a polysilicon film formed on the substrate.
9. 9 . The substrate processing apparatus of claim 8 , wherein the controller circuitry adjusts an amount of the silicic acid compound supplied to the processing tub based on the correlation data and a composition of the lot scheduled to be subjected to an etching processing.
10. 10 . The substrate processing apparatus of claim 9 , wherein the controller circuitry controls supply of the silicic acid compound to the processing tub before the etching processing of the lot scheduled to be subjected to the etching processing.
11. 11 . The substrate processing apparatus of claim 10 , wherein the controller circuitry controls replacement of, when it is determined that the concentration of the silicic acid compound in the etching liquid in the processing tub reaches a set threshold value after the etching processing of the lot scheduled to be subjected to the etching processing, at least a portion of the etching liquid in the processing tub before the etching processing of the lot.
12. 12 . The substrate processing apparatus of claim 9 , wherein the controller circuitry controls supply of the silicic acid compound to the processing tub during the etching processing of the lot.
13. 13 . The substrate processing apparatus of claim 12 , wherein the controller circuitry controls replacement of, when the concentration of the silicic acid compound in the etching liquid in the processing tub reaches a set threshold value during the etching processing of the lot, at least a portion of the etching liquid in the processing tub during the etching processing of the lot.
14. 14 . The substrate processing apparatus of claim 9 , wherein the correlation data include a calibration curve representing the correlation between the concentration of the silicic acid compound in the etching liquid in the processing tub and the etching rate of the polysilicon film formed on the substrate.
15. 15 . The substrate processing apparatus of claim 9 , wherein the controller circuitry adjusts a time of the etching processing to be performed on the lot, based on the concentration of the silicic acid compound in the processing tub, which is measured by the concentration measurement circuit.
16. 16 . The substrate processing apparatus of claim 9 , wherein a concentration sensor of the concentration measurement circuit, which is configured to measure the concentration of the silicic acid compound in the etching liquid in the processing tub, is a microwave plasma atomic emission spectrometer, an inductively coupled plasma optical emission spectrometer, or an inductively coupled plasma mass spectrometer.
17. 17 . The substrate processing apparatus of claim 9 , wherein the processing liquid is diluted aqueous ammonia, SC1 (a mixture of aqueous ammonia and aqueous hydrogen peroxide), NC2 (a mixture of an aqueous solution of choline and an aqueous hydrogen peroxide), or TMAH (tetramethylammonium hydroxide).
18. 18 . The substrate processing apparatus of claim 17 , wherein the controller circuitry controls an operation of the processing liquid supply so that a concentration of the processing liquid in the processing tub falls within a set concentration range.
19. 19 . The substrate processing apparatus of claim 9 , wherein a temperature of the etching liquid when performing the etching processing of the lot is in a range of 40° C. to 80° C.
20. 20 . The substrate processing apparatus according to claim 8 , wherein a concentration of silicic acid in the alkaline processing liquid is between 80 ppm and 160 ppm.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of Japanese Patent Application No. 2024-193788 filed on Nov. 5, 2024, the entire disclosures of which are incorporated herein by reference. TECHNICAL FIELD The various aspects and embodiments described herein pertain generally to a substrate processing method and a substrate processing apparatus. BACKGROUND Conventionally, there is known a technique of etching a polysilicon film formed on a substrate by using an alkaline processing liquid (see Patent Document 1). Patent Document 1: International Publication No. 2022-041076 SUMMARY In an exemplary embodiment, a substrate processing method includes generating an etching liquid by adding a silicic acid compound to an alkaline processing liquid; and etching a polysilicon film formed on a substrate with the etching liquid. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram illustrating a configuration of a substrate processing system according to an exemplary embodiment; FIG. 2 is an enlarged cross sectional view illustrating an example surface structure of a wafer according to the exemplary embodiment; FIG. 3 is a schematic block diagram illustrating a configuration of an etching apparatus according to the exemplary embodiment; FIG. 4 is a flowchart illustrating an example sequence of a control processing performed by the substrate processing system; FIG. 5 is a diagram illustrating an example variation in a concentration of a silicic acid compound in a processing vessel during an etching processing according to the exemplary embodiment; FIG. 6 is a diagram showing a relationship between the concentration of the silicic acid compound added to an etching liquid and a BT ratio; FIG. 7 is a diagram showing another example variation in the concentration of the silicic acid compound in the processing tub during the etching processing according to the exemplary embodiment; FIG. 8 is a diagram showing yet another example variation in the concentration of the silicic acid compound in the processing tub during the etching processing according to the exemplary embodiment; FIG. 9 is a diagram showing still yet another example variation in the concentration of the silicic acid compound in the processing tub during the etching processing according to the exemplary embodiment; FIG. 10 is a diagram showing still yet another example variation in the concentration of the silicic acid compound in the processing tub during the etching processing according to the exemplary embodiment; and FIG. 11 is a flowchart illustrating another example sequence of the control processing performed by the substrate processing system according to the exemplary embodiment. DETAILED DESCRIPTION In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current exemplary embodiment. Still, the exemplary embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein. Hereinafter, exemplary embodiments of a substrate processing method and a substrate processing apparatus according to the present disclosure will be described in detail with reference to the accompanying drawings. The present disclosure is not limited to the exemplary embodiments to be described below. Further, it should be noted that the drawings are schematic and relations in sizes of individual components and ratios of the individual components may sometimes be different from actual values. Even between the drawings, there may exist parts having different dimensional relationships or different ratios. Conventionally, there is known a technique of etching a polysilicon film formed on a substrate by using an alkaline processing liquid. In this conventional technique, however, there may be a significantly large difference between an etching amount of the polysilicon film at an opening side of a hole formed in the substrate and an etching amount of the polysilicon film at a bottom side of the hole. Therefore, there has been a demand for a technique capable of overcoming the aforementioned problem and improving the uniformity of the etching processing of the polysilicon film formed on the subs