JPS6384120A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a short-circuit of a wiring section due to remaining air bubble by periodically repeating the steps of dipping a substrate in an etchant, pulling it up, and blowing gas thereto to remove the bubbles on the surface. CONSTITUTION:A window is opened in an SiO2 film on an Si substrate formed with a diffused layer, aluminum is deposited, and a mask is attached. It is dipped in an etchant for 10 sec., removed, gas is blown for 5 sec., dipped again for 10 sec., and repeated 8 times. Thus, since the bubbles of H2 adhered to the substrate in the etchant is removed by blowing N2, it can be efficiently etched to prevent an improper short-circuit at a wiring section.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for wet etching a metal layer formed on a semiconductor substrate.

[Conventional technology]

Conventionally, a diffusion layer is formed in a predetermined region on one principal surface of a semiconductor substrate, an insulating film is formed to cover the entire surface, a window is opened in a predetermined region of the insulating film, and a metal such as aluminum is vapor-deposited over the entire surface. Electrodes and wiring portions were formed by photoetching. In the photo-etching process of this gold layer, the semiconductor substrate is etched using a photoresist as a mask material and an etching solution of phosphoric acid or nitric acid mixed with acetic acid or water as necessary. A wet etching method is used in which the material is immersed in an etching solution for the entire soaking time.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional etching method, when the semiconductor substrate is immersed in an etching solution and the etching progresses, for example, when etching an aluminum layer with phosphoric acid, Z
A reaction AJ+3HsPU4-+2kl PU4+3Hz occurs, and the generated hydrogen (H2) gas bubbles adhere to the aluminum layer, resist a, and the like. Therefore, in a semiconductor device processed in this manner and released from a T-substrate, electrodes or wiring portions are not formed in a prescribed manner in areas where air bubbles have adhered, which often results in short circuits and other defects. For that reason, attempts have been made to remove the hydrogen gas bubbles adhering to the semiconductor substrate by stirring the etching solution and using ultrasonic imaging, but it has been difficult to remove the hydrogen gas bubbles from the metal layer. [Means for solving all problems] The method for manufacturing a semiconductor device of the present invention is based on the method for manufacturing a semiconductor device of the present invention, in which the entire part is peeled off, making it difficult to perform the entire etching as specified. In the method of manufacturing a semiconductor device, the method includes a step of forming a metal layer pattern by selectively removing a metal layer by wet etching, in which the substrate is immersed in an etching solution for a predetermined period of time, then taken out of the etching solution, and the metal layer is etched. (2) is characterized in that the entire pattern of the metal layer is formed by etching by periodically repeating the step of blowing gas onto the layer surface to remove all the bubbles attached to the surface of the metal N.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the method of etching a semiconductor device according to the present invention.

A heater 3 for raising the temperature of the etching solution is installed at the bottom of the tank 2 containing the etching solution 1, and this heater 3 is connected to a temperature controller 4. Further, above the tank 2, an elevating device 7 is arranged which stores the semiconductor substrate 5 and moves the carrier 6'i up and down (in the direction of the arrow in the figure) to put the semiconductor substrate into and take it out of the etching solution 1. ing. This elevating device 7 has a mechanism that allows the carrier 6 to be immersed in the etching liquid 1 for a predetermined period of time, and to be pulled out from the etching liquid 1 for a predetermined period of time, as well as the number of times of loading and unloading. The carrier 6 is provided with a groove in which a large number of semiconductor substrates 5 can be stored in parallel to each other. Gas blowing nozzles 8 and 9 are installed above the etching liquid surface so as to face each other so that the gas blows out parallel to the surface of the semiconductor substrate. This gas blow @
A gas 10.11 such as gas, nitrogen, etc. is blown out from the outlet 8.9 to remove bubbles of constant hydrogen gas generated and attached to the surface of the semiconductor substrate.

When proceeding with the etching process using such an apparatus, the two semiconductor substrates 5 that are attached to the lifting device 7 and etched onto the T-carrier 6 are stored parallel to each other.

Next, the lifting device 7e is operated to lower the carrier 6 into the tank 2 filled with the etching solution 1, and the entire semiconductor substrate is immersed in the etching solution. Next, after a predetermined period of time has elapsed, the lifting device 7 is opened and the carrier 6 is pulled up from the etching solution 1. Next, gas such as air or nitrogen 10°11
Spray with gas blowing nozzles 8 and 9.

By repeating this process several times periodically, the number of hydrogen gas bubbles generated and attached to the surface of the semiconductor substrate is greatly reduced, so that the etching defects can be completely removed and etching can be carried out for the prescribed number of times. This makes it possible to eliminate short circuits in the wiring section due to residual hydrogen gas bubbles, which have frequently occurred in the past.

FIG. 2 is an explanatory diagram showing the time cycle of loading and unloading the semiconductor substrate into and out of the etching solution and the gas blowing timing in the embodiment shown in FIG. 1. The vertical axis shows the height position of the carrier, and the horizontal axis shows the etching time. It is assumed that the center line indicates the entire surface of the etching solution, and that there is etching solution below it. a%b,c,...
n indicates the gas blowing timing.

Next, a specific example of the etching process QJ1 will be explained. After forming a predetermined diffusion region on a semiconductor substrate and opening a predetermined window in the oxide film formed thereon, an aluminum random film is deposited to a thickness of 1.0 μm, and the predetermined region is masked for etching. The temperature of the etching solution is raised to 40° C., and the semiconductor substrate is immersed in this solution. After immersing for 10 seconds, it was taken out of the etching solution, nitrogen gas was sprayed for 5 seconds, and the process of immersing for 10 seconds was repeated 8 times. In this way, bubbles of the cleaning gas adhering to the surface of the semiconductor substrate in the etching solution can be removed by blowing nitrogen gas after the bubbles are removed from the etching solution. This is done by repeating 1G, which prevents insufficient etching due to adhesion of hydrogen gas bubbles, allows for efficient etching as specified, and prevents defects due to short circuits in wiring parts. Not at all.

〔Effect of the invention〕

As explained above, in the present invention, after the semiconductor substrate is removed from the etching solution during etching, a gas such as nitrogen or air is blown onto the surface of the semiconductor substrate, and a reaction between the metal layer and the etching solution occurs in the etching solution. Since it is possible to remove hydrogen gas bubbles that are generated and adhere to the semiconductor substrate surface, it is possible to prevent short-circuiting of the metal layer due to the adhesion of hydrogen gas bubbles, and the electrode or fc made of the metal layer is The parts can be formed in a predetermined manner. Furthermore, the above metal layer can be applied to etching not only aluminum but also other metal layers that generate gas during etching, and exhibits excellent effects. Furthermore, since the removal of hydrogen gas bubbles according to the present invention is very efficient, it has the effect of improving the manufacturing yield of semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a method for manufacturing a semiconductor device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the time cycle of putting a semiconductor substrate in and out of an etching solution and the gas blowing timing of the present invention. It is. 1... Etching liquid, 2... Tank, 3... Heater,
4... Temperature controller, 5... Semiconductor substrate, 6... Carrier, 7... Lifting device, 8, 9... Gas blowing nozzle, 10... Gas, a, b, c, n...
Gas blowing timing, L...Etching liquid level. Agent Patent Attorney Hara Uchi - Par・＼8・1 “
1 ′ °, nee・

Claims (1)

[Claims] In a method for manufacturing a semiconductor device including a step of selectively removing a metal layer deposited on a semiconductor substrate by wet etching to form a metal layer pattern, the substrate is immersed in an etching solution for a predetermined time and then etched. Manufacture of a semiconductor device characterized in that the metal pattern is formed by etching the metal pattern by periodically repeating a step of removing the metal layer from the liquid and blowing gas onto the metal layer surface to remove bubbles attached to the metal layer surface. Method.