JPS6127633A - Plasma etching device - Google Patents

Abstract

PURPOSE:To make it feasible to perform precise etching process by a method wherein a carrier is provided to carry a supporter to support a substrate into or out of plasma produced between flat electrodes in parallel with each other. CONSTITUTION:A substrate 1 is arranged on a supporter 4a by means of a substrate carrier. The substrate 1 is preliminarily supplied with power so that reaction gas led from a reaction gas leading tube may produce stable plasma 8 between flat plate made cathode 6 and anode 7. Firstly the supporter 4a loaded with the substrate 1 is placed on the cathode 7 in the plasma 8 by means of a carrier and the substrate 1 is etched as it is for specified time. Secondly the supporter 4a after finishing the etching process is carrier out of the plasma 8 and the semiconductor substrate 1 on the supporter 4a is carried out by the substrate carrier. Through these procedures, the semiconductor substrate 1 on the supporter 4a may not be supplied with any unstable high voltage generated in case plasma is produced or discharged since the substrate 1 may be etched within the plasma 8 in stable status with power preliminarily supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a plasma etching apparatus used for manufacturing semiconductor devices.

[Prior art]

It is known that in conventional plasma etching apparatuses, abnormal voltages occur when power is turned on and when power is turned off.

That is, when power is turned on, the gas between the electrodes is not in a plasma state, so the electrical resistance is high.

Therefore, as shown in FIG. 1, an unstable high voltage v1 is applied between the electrodes during a short time t1 when power is turned on. When the gas between the electrodes enters a plasma state, the impedance between the electrodes decreases and the voltage becomes low and constant as shown at time t2. Furthermore, when the power is cut off and the plasma is extinguished, a high voltage v2 as shown at 1 hour t3 is generated.

In this way, in conventional plasma etching equipment,
Since an abnormal voltage is applied to the semiconductor substrate, the elements formed on the semiconductor substrate are damaged by junctions and the like, resulting in deterioration of element performance.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma etching apparatus that eliminates the above-mentioned drawbacks and enables high-quality etching processing.

According to the present invention, since the semiconductor substrate is carried in between the electrodes where stable plasma is generated and carried out, the abnormal voltage that occurs when power is turned on and off is not applied.

[Structure of the invention]

The plasma etching apparatus of the present invention includes a holding plate for holding a semiconductor substrate, a substrate carrying means for placing the semiconductor substrate on the holding plate, and a substrate carrying means for carrying the holding plate into plasma generated between parallel plate electrodes. The apparatus also includes a transport stage for transporting the semiconductor substrate, and a substrate transport means for taking out the semiconductor substrate after etching from the holding plate. In such a configuration, the substrate carrying means and the parallel plate electrode are always in the same vacuum system, and there is a space between the parallel plate electrode and the holding plate before and after the etching process to avoid applying an electric field to the holding plate. A shield electrode is provided. When the shield electrode is a cathode-coupled type that supplies an aF source to the wafer support side as in the embodiment described later, it is fixed to the GND potential, which is the same potential as the anode, but in an etching device that supplies an RF source to the anode side, it is a floating electrode. It is.

[Explanation of Examples]

Next, the present invention will be explained using an example and with reference to one drawing.

FIGS. 2(a) to 2(C) are schematic cross-sectional views for explaining the movement of the semiconductor substrate and the holding plate in one embodiment of the present invention.

As shown in FIG. 2(a), a supply cassette 2 containing a plurality of semiconductor substrates 2 is placed in a vacuum container 1 of a plasma etching apparatus. One semiconductor substrate 1 is placed from the supply cassette 2 on a holding plate 4a made of ceramic, quartz, or the like by means of substrate carrying means (not shown) made of, for example, a conveyor belt or a conveyor fork. By this time, electricity and force have been applied in advance so that the reaction gas introduced from the reaction gas introduction tube 5 forms a stable plasma 8 between the flat anode 6 and the cathode 7. Na゛O1
A shield electrode 2 shields plasma from the semiconductor substrate before and after etching.

Next, as shown in FIG. 2(b), the holding plate 4a on which the semiconductor substrate 1 is placed is placed on the cathode 7 in the plasma 8 by a conveying means (not shown) consisting of a conveying belt or a rotating mechanism. It will be destroyed. In this state, the semiconductor substrate 1 on the holding plate 4a is etched for a prescribed period of time. During this time, the next semiconductor substrate l is placed on the holding plate 4b.

Next, as shown in FIG. 2, the holding plate 4a after etching is carried out from the plasma 8 by a conveying means, and then the semiconductor substrate 1 on the holding plate 4a is carried out by a substrate carrying means such as a conveying fork or a conveying belt. It is taken out by means (not shown) and stored in the storage cassette 9. During this time, the holding plate 4
b is placed in the plasma 8 by the transport means, and the semiconductor substrate 1 is taken out from the supply cassette 1 and placed on the next holding plate 4C. In the figure, lO is the exhaust pipe,
11 is a high frequency power source.

According to one embodiment of the present invention, the semiconductor substrate 1 placed on the holding plate is etched by being placed in the plasma 8 which is in a stable state after power is turned on.・You will not be exposed to the unstable high voltage that occurs during extinction. Therefore, the elements formed on the semiconductor substrate l will not be damaged.

FIG. 3 is a partially cutaway perspective view of an important part of an embodiment of a pond according to the present invention.

In FIG. 3, the semiconductor substrate 101 housed in the supply cassette 107A is taken out by the vertical movement of the cassette support 108 and the conveyor belt 109/V, and is transferred to the conveyor fork 110A.

The transport 7 oak 110A places the semiconductor substrate 101,
The semiconductor substrate 101 is moved in parallel onto the holding plate 1020 and the substrate holding portion 112A. At this time, the substrate holding part 11
The piston 111 rises from the bottom of the 2N, and the semiconductor substrate 10
Push up 1. and.

When the transport 7 oak 11ON moves to its original position, the piston 111 descends and the semiconductor substrate 101 is moved to the substrate holding part 11.
Place it on 24. The substrate holding portion 112N is formed of a circular concave portion with a taper, and is configured to accurately place and hold the semiconductor substrate 101.

The holding plate 102 made of ceramic, quartz plate, etc. is formed in the shape of an equilateral triangle centered on the rotating shaft 106, and three substrate holding parts 112 (1
12A, 112B, 112C) are formed.

When the semiconductor substrate 101 is placed on the substrate holder 112A, the holder 102 rotates 120 degrees around the rotation axis 106, and the substrate holder 112 is placed between the flat anode 104 and the cathode where plasma is generated in a stable state. Move between 105 and 105. At this time, the plasma is separated from the semiconductor substrate before and after the etching process by the shield 1tM113. After the semiconductor substrate 101 has been etched for a predetermined time, the holding plate 102 rotates again, and the substrate holding part 112B on which the next semiconductor substrate is placed moves between the anode and cathode 104 and 103.

On the other hand, the etched semiconductor substrate 101 on the substrate holder 112A is pushed up by the piston 111 and transferred to the conveying fork 110B, which has moved in parallel. When the transport fork 110B returns to its original position, it is stored in the storage cassette 107B by the transport belt 109B.

In this way, the semiconductor substrates 101 in the supply cassette 107A are sequentially transferred to the substrate holder 112, etched in stable plasma, and then automatically stored in the storage cassette 107B.

Supply cassette 107A, storage cassette 107, holding substrate 1021, and anode 10 connected to reaction gas core 105
4 etc. may all be placed in the same vacuum container, or each cassette, conveyor belt, and conveyor fork may be placed in a spare vacuum container.

In the above embodiment, a triangular holding plate is used, but a circular holding plate may also be used, and three or more radix holding parts may be used to continuously hold the semiconductor substrate. It is now possible to expose the body to plasma.

〔Effect of the invention〕

As explained in detail above, the present invention enables a semiconductor substrate to be etched in stable plasma, thereby providing a plasma etching apparatus capable of performing high-quality etching processing without damaging devices. Therefore, it has a great effect on the manufacturing of semiconductor devices.

[Brief explanation of drawings]

Figure 1 is a diagram showing the change in voltage with respect to time between the electrodes of a plasma etching device, and Figures 2 (a) to (C).
3 is a schematic cross-sectional view for explaining the movement of a semiconductor substrate and a holding plate in one embodiment of the present invention, and FIG. 3 is a partially cutaway perspective view of another embodiment of the present invention. 1... Vacuum container, 2... Supply cassette, 3... Semiconductor substrate, 4a, 4b, 4c...
...Holding plate, 5...Reaction gas introduction pipe, 6...
...Anode, 7...Cathode, 8...Plasma, 9...Storage cassette, 10...
・Exhaust pipe, 11... High frequency power supply, 12...
...Shield electrode, 101...Semiconductor substrate, 1
02... Holding plate, 103... Cathode, 1
04... Anode, 105... Reaction gas introduction tube, 106... Rotating shaft, 107A...
・Supply cassette, 107B...Storage cassette,
108...Cassette support stand, 109N, 109
B... Conveyor belt, 11 (1,110B...
...Transportation fork, 111... Piston, 1
12... Substrate holding part, 113... Shield electrode.

Claims (1)

[Claims] A holding plate for holding a semiconductor substrate, a substrate carrying means for placing the semiconductor substrate on the holding plate, a conveying means for carrying the holding plate into and out of plasma generated between parallel plate electrodes, and etching. 1. A plasma etching apparatus comprising: substrate unloading means for taking out a semiconductor substrate after completion of etching from the holding plate.