JPS607382B2 - Decompression etching method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reduced pressure etching method, and more particularly to a reduced pressure etching method for naturally defoaming microbubbles generated during etching.

For example, a method for forming aluminum wiring on a semiconductor wafer by etching is as shown in FIG. A method of etching by releasing.

Alternatively, as shown in FIG. 1B, a method is known in which a semiconductor wafer 2 is arranged along a plane 4 and etching is performed by spraying a pressurized etching liquid 3 from above the plane 4. The reason why the semiconductor wafer 2 is etched by bombarding the semiconductor wafer 2 with the etching solution 3 is that, during etching, the chemical reaction between the semiconductor wafer 2 and the etching solution 3 generates, for example, hydrogen (ratio), which produces minute bubbles. is removed by the power of the flowing water of the etching solution 3.

However, in the conventional etching method described above, the generated microbubbles could not be easily and sufficiently removed.

The reason for this is thought to be that when air bubbles are removed by the force of the flowing water of the etching solution 3, a portion is inevitably created that is not exposed to the force of the flowing water, and the bubble remains in that portion. In addition, in the conventional etching method, the forehead slope 1,
Since the semiconductor wafers 2 are aligned along the plane 4, space is limited, and the amount of processing of the semiconductor wafers 2 is limited.

Furthermore, in the conventional etching method, it is difficult to automate the etching work because it is affected by the shape and posture of the semiconductor wafer 2.

The present invention has been made to overcome the above-mentioned conventional drawbacks, and its purpose is to provide a reduced-pressure etching method that can easily remove air bubbles generated by chemical reactions during etching.

2. It is an object of the present invention to provide a reduced pressure etching method that increases the amount of etching processing.

3. To provide a reduced-pressure etching method for automating etching work.The basic structure of the present invention to achieve the above object is an etching method for etching semiconductor components in a reduced-pressure chamber, as shown in the drawings below. The present invention will be explained in detail by means of examples shown.

FIG. 2 is a perspective view in which a part of the reduced pressure etching apparatus used for carrying out the reduced pressure etching method of the present invention is partially sectionalized and simplified. In the figure, this reduced pressure etching apparatus 6 is equipped with an etching tank 7 containing a reduced pressure chamber 7a, and this reduced pressure chamber 7a is kept at a pressure of 50 Torr to 300 Ton by a reduced pressure pump 8. Furthermore, a trap 10 and a leak valve 11 are installed in the Rentsu pipe 9 that connects the decompression chamber 7a and the decompression pump 8, so that the gas generated in the decompression chamber 7a can be extracted and leaked before the decompression chamber 7a is opened. I have to. And the decompression chamber 7
An etching solution 12 is stored at the bottom of a, and has a sufficient amount for etching processing. Further, the etching solution 12 is placed below the decompression chamber 7a at a temperature (4000°C) where it is most active.
A constant temperature chamber 13 is provided to maintain the temperature at 60:00 p.m. Next, a reduced pressure etching method of the present invention using such a reduced pressure etching apparatus 6 will be explained.

First, semiconductor wafers 14, which are objects to be etched, are placed in a horizontal cartridge 15 in parallel, and the horizontal cartridge 15 is immersed in the etching solution 12 in the reduced pressure chamber 7a. This cartridge 15 is moved into the decompression chamber 7a.
When inserting the etching tank 7 into the chamber, raise the upper cover 7b of the etching tank 7, insert the etching tank 7, close the upper cover 7b again, operate the vacuum pump 8 to reduce the pressure in the vacuum chamber 7a, and remove the semiconductor wafer 14.
Start etching. When etching begins due to a chemical reaction between the semiconductor wafer 14 and the etching solution 3, hydrogen gas is generated in the case of aluminum etching, and this hydrogen gas is mixed with the etching solution 3.
By forming microbubbles inside and receiving further reduced pressure,
These microbubbles become larger, move away from the semiconductor wafer 14, rise to the upper part of the decompression chamber 7a, and are exhausted through the transport pipe 9. Note that the cartridge housing the semiconductor wafer 14 does not have to be the horizontal cartridge 15, and may be a vertical cartridge (not shown).

In this case, since the semiconductor wafers 14 are vertically arranged in parallel, the etching tank 7 is also elongated. In the above embodiment, the semiconductor wafer 14 is placed in the cartridge 1.
5, the etching of the wafer 14 is performed by arranging the wafer 14 along the plane 16a of the rotary table 16, as shown in FIG.
Etching liquid 17 is supplied from above this plane 16a,
A method may also be used in which these are built into the reduced pressure chamber 18 and subjected to etching treatment. In this case, the etching liquid 17 can be spread evenly over the wafer 14.
As is clear from the above explanation, according to the present invention, since the etching process of the semiconductor wafer is performed in a reduced pressure chamber, microbubbles such as hydrogen (broad) generated by the chemical reaction between the wafer and the etching solution are greatly reduced by the reduced pressure action. This increases the buoyancy of the wafer, allowing it to rise above the surface of the wafer and allow for natural degassing.

Therefore, the bubbles interfere with etching, and it is possible to prevent the occurrence of etching defects on the semiconductor wafer. Further, according to the present invention, etching can be performed with a large number of semiconductor wafers arranged in parallel, facing each other, so that the etching processing capacity of semiconductor wafers can be greatly increased.

Further, according to the present invention, since it is not affected by the shape and posture of the semiconductor wafer, numerous effects such as sufficient automation of etching work can be obtained.

[Brief explanation of the drawing]

1A and 1B are explanatory diagrams showing a conventional etching method, and FIG. 2 is a perspective view of a reduced pressure etching apparatus used in carrying out the reduced pressure etching method of the present invention, with part of the reduced pressure etching apparatus being partially sectioned and partially omitted; FIG. 3 is a partially sectional perspective view showing another embodiment of the reduced pressure etching apparatus. 1... Inclined surface, 2... Semiconductor wafer, 3
... Etching solution, 4 ... Plane, 6 ...
- Decompression etching device, 7... Etching tank, 8... Decompression pump, 9... Communication pipe, 10... Trap, 11... Leak valve, 12
...Etching solution, 13...Thermostat, 14...
...Semiconductor wafer, 15...Horizontal force-torage, 16...Rotary table, 16a.1...
...Plane, 17... Etching solution, 18...
・Decompression chamber. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A reduced pressure etching method in which a part to be etched is etched by chemical etching, in which a chemical reaction treatment between the part to be etched and an etching solution is performed in a reduced pressure chamber.