JPS63211725A - Etching - Google Patents

Abstract

PURPOSE:To check occurrence of foaming and speed up control of reaction speed by performing etching treatment while controlling the vessel internal pressure inside a pressure vessel. CONSTITUTION:Semiconductor wafers 3 housed in a wafer carrier 30 are dipped in an etching liquid 2 filled in a pressure vessel 1 and a pressure lid 4 is closed. A valve 7 between the piping 8 connected to a pressure bomb and the pressure vessel 1 is opened to introduce pressure gas from the bomb into the pressure vessel 1 to press the inside of the pressure vessel 1. The pressure is monitored by a pressure gauge 6 for being sent to a controller 9. The controller 9 controls a reducing valve 5 between the piping 10 connected to the pressure valve 7 together with an exhaust duct and the pressure vessel 1 in order to hold the inside of the pressure vessel 1 at desired pressure. The semiconductor wafers 3 are given etching treatment having an etching pattern as a mask in an etching liquid 2 for prescribed hours to be pulled up from the etching liquid 2 in order to undergo washing treatment in the other vessel. Thereby, a phenomen to disturb material movement due to foams at fine holes to be etched can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an etching method, and particularly to a method for forming fine patterns with high precision in an etching system in which gas is generated during an etching reaction.

[Prior art] Conventionally, in this type of wet etching system,
Etching was carried out under various reaction conditions, such as the concentration of the etching solution, its composition, and the number of reaction sites.

[Problems to be Solved by the Invention] Conventionally, in a wet etching system in which gas is generated by the reaction between the object to be etched and the etching liquid, the amount of gas generated and the diameter of the generated bubbles cannot be controlled, so the generated bubbles are It has the disadvantage that it adheres to a part of the fine pattern of the object to be etched, and the bubbles cut off contact with the etching solution, stopping subsequent reactions and inhibiting the formation of the fine pattern. .

Furthermore, in the conventional method, the reaction rate is controlled by changing the reaction temperature, so it is impossible to quickly change the reaction rate.

An object of the present invention is to provide an etching method that suppresses the generation of bubbles and speeds up reaction rate control.

[Differences between the invention and the prior art] In contrast to the conventional etching method described above, the present invention adds a new reaction pressure (particularly applied It has an original content in that it incorporates pressure (pressure) to perform etching processing.

[Means for Solving the Problems] The present invention provides an etching method in which an etching pattern that is resistant to an etching solution is formed on an etching layer of an object to be processed, and the etching layer is etched using the etching pattern as a mask. An etching method is characterized in that the etching process is carried out in a pressure vessel while controlling the internal pressure of the vessel.

[Examples] Examples of the present invention will be described below with reference to the drawings.

(Example 1) FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

This embodiment is applied to a batch type semiconductor wafer sweat etching apparatus.

An etching pattern that is resistant to etching liquid is formed on the etching layer of the object to be processed, and the etching layer is etched using the etching pattern as a mask. That is, in FIG. 1, the semiconductor wafer 3 housed in the wafer carrier 30 is immersed in the etching liquid 2 filled in the pressure vessel 1, and the pressure M4 is closed. By opening the valve 7 between the pipe 8 connected to the pressure cylinder and the pressure vessel 1, pressure gas is introduced into the pressure vessel 1 from the cylinder, and the inside of the pressure vessel 1 is pressurized. The pressure inside the pressure vessel 1 is monitored by a pressure gauge 6 and sent to a controller 9. The controller 9 controls the pressurization valve 7 and the pressure reduction valve 5 located between the pressure vessel 1 and the pipe 10 leading to the exhaust duct.
Maintain the desired pressure inside. After the semiconductor wafer 3 is etched for a predetermined time in the etching solution 2 using the etching pattern as a mask, it is lifted out of the etching solution 2 and subjected to water washing in a separate tank.

(Example 2) FIG. 2 is a longitudinal sectional view showing a second embodiment of the invention.

This embodiment is applied to a single-wafer semiconductor wafer sweat etching apparatus.

In FIG. 2, the pressure vessel 12 is equipped with a preliminary pressure chamber 11 for a wafer load cassette and a preliminary vacuum chamber 21 for a wafer unload cassette, and semiconductor wafers 3 are transferred one by one from a wafer load cassette 28 and subjected to an etching process. receive. The pressure vessel 12 is pressurized by opening the pressure valve 15 located between the pressure vessel 12 and a pipe 16 connected to the pressure cylinder, and introducing the pressure inside the pressure cylinder.

The pressure within the pressure vessel 12 is monitored by a pressure gauge 20 and sent to a controller 19. controller 19
controls the pressurization valve 15 and the pressure reduction valve 17 located between the pressure vessel 12 and the piping 18 leading to the exhaust duct to maintain the pressure inside the pressure vessel 12 at a desired pressure.

The wafer 25 held by a wafer chuck 27 connected to a rotary motor is rotated under pressure and etched by the etching liquid discharged from the etching liquid nozzle 14. After etching is completed, the wafer 25 is cleaned with deionized water discharged from the deionized water nozzle 13 and then spun. After drying, the wafer is transported to and stored in the cassette 29 in the preliminary vacuum chamber 21 for wafer unload cassette. 22 is a drain valve, 23 is a drain reservoir, and 24 is a valve for opening and closing the drain 26.

[Effects of the Invention] As explained above, in the case of forming micropores in the present invention, bubbles are generated by performing the etching process under pressure in a wet etching system where bubbles are generated due to the reaction between the layer to be etched and the etching solution. By reducing the diameter of the bubbles or by dissolving the generated bubbles into the liquid, it is possible to prevent the phenomenon in which air bubbles impede mass transfer in the fine pores of the etched object, and the object to be etched can be uniformly etched. It is possible to perform etching and open micropores with a high yield.

In addition, in the above etching system, applying pressure causes a phenomenon in which the equilibrium of the chemical reaction is shifted and the reaction rate decreases. This has the effect of increasing the degree of reaction and terminating the reaction.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a batch type semiconductor wafer etching apparatus according to a first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing a single wafer type semiconductor wafer etching apparatus according to a second embodiment of the present invention. It is a front view. 1... Pressure vessel 2... Etching liquid 3.
...Semiconductor wafer 4...Pressure lid 5...Pressure reduction valve 6...Pressure gauge 7...Pressure valve
9...Controller 12...Pressure vessel
13...Pure water nozzle 14...Etching liquid nozzle

Claims (1)

[Claims] (1) In an etching method in which an etching pattern that is resistant to an etching solution is formed on an etching layer of a workpiece, and the etching layer is etched using the etching pattern as a mask, the internal pressure of the container is An etching method characterized by performing etching treatment while controlling.