Plasma etching apparatus

Abstract

The present invention relates to an etching apparatus which is capable of etching the entire surface of a substrate uniformly even if the substrate is large-sized and in which deterioration of etching shape does not occur. An etching apparatus 1 has a chamber 2 having a plasma generating space 9 and a processing space 6, a coil 16 disposed on the outside of a portion corresponding to the plasma generating space 9, a platen 10 which is provided in the processing space 6 and on which a substrate K is to be placed, a processing gas supply mechanism 19 for supplying a processing gas into the plasma generating space 9, an RF power supply mechanism 17 for supplying RF power to the coil 16, and a power supply mechanism for platen 13 for supplying RF power to the platen 10. A cylindrical plasma density adjusting member 20 which is made of a conductive material grounded is fixedly provided on an inner wall of the chamber 2 between the plasma generating space 9 and the platen 10. While plasma passes through the plasma density adjusting member 20, the in-plane density of the plasma is equalized, and then the plasma is guided to the substrate K.

Description

technical field [0001] The present invention relates to a plasma etching device capable of plasmating etching gas to etch the surface of a substrate such as a silicon substrate or a glass substrate. Background technique [0002] Conventionally, devices disclosed in JP-A-2006-80504 (Prior Art 1) and JP-A-2006-60089 (Prior Art 2) are known as devices for plasma etching silicon substrates. [0003] like Image 6 As shown, the plasma etching device 101 of the above-mentioned previous example 1 includes: a cylindrical chamber 102, a plasma generation space 109 is set on its upper side, and a processing space 110 is set on its lower side; The outer side of the chamber 102 corresponding to the plasma generation space 109 is arranged so as to be wound thereon; the high frequency power supply mechanism 104 for supplying high frequency power to the coil 103; the mechanism for supplying etching gas to the plasma generation space 109 Etching gas supply mechanism 105; substrate mounting...

AI Technical Summary

Problems solved by technology

[0011] That is, in the above-mentioned plasma etching apparatus 101, since the plasma generation space 109 is large, it is easy to align with a relatively large substrate structurally. After the plasma generation space 109 is enlarged, the in-plane density Pm of the plasma generated in the plasma generation space 109 will become a concave density distribution that is high in the part close to the coil 103 and low in the central part, The plasma of such density acts directly on the substrate K, thus causing the surface of the substrate K to not be uniformly etched

[0012] Especially for the outer peripheral portion of the substrate K, even if the in-plane density Pm of the plasma is uniform, the etching rate tends to be higher than that of the central portion, so the etching tends to proceed more easily. Therefore, when the density distribution becomes concave as described above, It is easier to etch the outer peripheral part of the substrate K, so the entire surface of the substrate K cannot be uniformly etched

[0013] Also, when the plasma density in the outer peripheral portion is high, for example, in the case where deep cavities are formed on the substrate K, as Figure 8 As shown, the periphery of the entrance portion of the cavity 300 is etched by high-density ions, and the shape of the entrance portion becomes wedge-shaped. In addition, the surface becomes rough due to sputtering, which causes the problem of deterioration of the etched shape.

[0014] On the other hand, for the plasma etching device 201, since the volume of the plasma generation space 209 is small, even if the high-frequency power applied to the coil 203 is small, high-density plasma can be generated, and because its plane The internal density Pm also becomes convex, so for a relatively small substrate K, the entire surface can be uniformly etched. If the size is increased, the plasma generated in the plasma generation space 209 is difficult to act on the outer periphery of the substrate K, and in this case, the entire surface of the substrate K cannot be uniformly etched.

[0015] On the other hand, if the plasma generation space 209 is enlarged corresponding to the enlargement of the substrate K, the same problem as that of the above-mentioned plasma etching apparatus 101 will arise.

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