JP2005243707A - Plasma generation method and plasma generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma generation method in which high processing control of a precision is possible in etching processing or padding. <P>SOLUTION: The plasma generation method includes a gas discharging step of exhausting in a chamber 20, a first gas leading step of introducing a first reactant gas in the chamber 20, a first plasma generation step of generating a plasma based on the first reaction gas in the chamber 20, a second gas leading step of introducing the second reactant gas in the chamber 20, and a second plasma generation step of generating the plasm based on the second reaction gas in the chamber 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plasma generation method and a plasma processing apparatus used for manufacturing a thin film element on a semiconductor device or a liquid crystal panel, and more particularly to an apparatus capable of highly accurate control of etching processing and embedding.

  A dry etching apparatus is known as one of manufacturing apparatuses for manufacturing a semiconductor device using a semiconductor substrate (hereinafter referred to as “wafer”) (see, for example, Patent Document 1). In the dry etching equipment, in order to remove unnecessary films when manufacturing semiconductor devices, plasma is generated by applying high-frequency power to the introduced etching process gas (reactive gas), and the process gas is activated. (Hereinafter referred to as “plasma state”) and is removed (etched) by reacting with the film.

In a conventional dry etching apparatus, a wafer to be processed is attracted and held on a stage disposed in a chamber. After the inside of the chamber is evacuated by a vacuum pump and the pressure is reduced, an etching process gas (reaction gas) is supplied into the chamber from a gas introduction pipe. The process gas introduced into the chamber is pressure controlled by a vacuum pump. Then, after the pressure of the process gas is stabilized, high frequency power is applied from a high frequency power source to the lower electrode connected to the stage, and plasma is generated. At this time, the upper electrode facing the lower electrode and the inner wall of the chamber are connected to the ground potential. Then, the process gas becomes a highly reactive plasma state, and reacts with the film on the wafer to be etched away.
JP 2001-244239 A

  The dry etching apparatus described above has the following problems. That is, in dry etching, it may be required to precisely control the processed shape of the film to be etched. However, it is known that during etching, a film to be etched is scraped and a reaction product is generated in the gas phase, which affects the etching rate, the etching selectivity, and the processing shape.

  Moreover, as a phenomenon during etching, the formation of a deposited film on the sidewalls of holes and grooves other than etching and the inner wall of the processing vessel and the interaction between the deposited film and plasma occur. It is not particularly controlled.

  On the other hand, a plasma processing method such as plasma CVD has a problem that the deposited film on the side wall grows in an overhang shape when a fine hole or groove is buried, and a cavity remains inside after filling.

  Accordingly, an object of the present invention is to provide a plasma generation method and a plasma processing apparatus capable of performing highly accurate processing control in etching processing and embedding.

  In order to solve the above problems and achieve the object, the plasma generation method and the plasma processing apparatus of the present invention are configured as follows.

(1) An exhaust process for exhausting the interior of the chamber, a first gas introduction process for introducing a first reactive gas into the chamber, and a first plasma for generating plasma based on the first reactive gas in the chamber A generating step; a second gas introducing step for introducing a second reactive gas into the chamber; and a second plasma generating step for generating plasma based on the second reactive gas in the chamber. It is characterized by.

(2) In the plasma generation method described in (1) above, after the first plasma generation step, a first exhaust step for exhausting the chamber is performed, and after the second plasma generation step, A second exhaust process for exhausting the inside of the chamber is performed.

(3) The plasma generation method according to (1), wherein the first plasma generation step and the second plasma generation step are alternately performed.

(4) In the plasma generation method described in (1) above, the first gas has a higher film deposition property than the second gas.

(5) In the plasma generation method described in (1) above, the first gas has a lower etching property than the second gas.

(6) The plasma generation method described in (1) above, comprising a rare gas introduction step for introducing a rare gas different from the first and second gases into the chamber. To do.

(7) A chamber, an exhaust device for exhausting the inside of the chamber, a first gas introduction unit that is connected to the chamber and introduces a first reaction gas from the outside, and is connected to the chamber and externally A second gas introduction unit for introducing a second reaction gas from the first reaction gas, a plasma generation unit for generating plasma in the chamber based on the first reaction gas or the second reaction gas, and the first and second And a control unit for controlling the timing of introducing the first and second reaction gases by the second gas introducing unit and the timing of exhausting the chamber by the exhaust device.

  According to the present invention, it is possible to perform highly accurate processing control in etching processing and embedding.

  FIG. 1 is a schematic diagram showing a dry etching apparatus (plasma generating apparatus) 10 according to an embodiment of the present invention. The dry etching apparatus 10 includes, for example, a chamber 20 made of a metal vacuum vessel such as aluminum or stainless steel, a plasma generation mechanism 30 that generates plasma in the chamber 20, and a gas introduction mechanism that introduces a reaction gas or the like into the chamber 20. 40.

  The chamber 20 has a gas inlet 21 for introducing gas into the chamber 20, an exhaust pump 22 that exhausts and depressurizes the chamber 20, and adjusts the pressure in the chamber 20 within a range of 0.05 Pa to 500 Pa. A pressure adjusting unit 23, a pressure sensor 24 that measures the pressure in the chamber 20, and a loading / unloading port 25 for a semiconductor wafer W that is an object to be processed are provided.

  The plasma generation mechanism 30 includes a lower electrode 31 disposed in the chamber 20, a holder 32 provided on the lower electrode 31 and supporting the semiconductor wafer W from the lower side, and several hundred kHz to several hundred MHz. And a power supply 34 for supplying power of frequency via a matching circuit 33. The matching circuit 33 has a function of controlling ion energy incident on the semiconductor wafer W. The chamber 20 further includes a high-frequency antenna 35 disposed opposite to the lower electrode 31 and a power source 37 that supplies power of a frequency of several hundred kHz to several hundred MHz to the high-frequency antenna 35 via a matching circuit 36. ing.

  The gas introduction mechanism 40 includes a first reaction gas supply unit 41, a gas flow rate adjustment valve 42 for adjusting a gas flow rate from the first reaction gas supply unit 41, a second reaction gas supply unit 43, and the second reaction. A gas flow rate adjusting valve 44 for adjusting a gas flow rate from the gas supply unit 43, an Ar gas supply unit 45 which is a rare gas, a gas flow rate adjusting valve 46 for adjusting a gas flow rate from the Ar gas supply unit 45, and And a pipe 47 that connects the gas inlet 21 of the chamber 20.

  Further, the gas flow rate adjusting valves 42, 44, 46 are adjusted by a controller 48 for controlling the flow rate with respect to time, and a pulse generator 49 is connected to the controller 48.

As the first reaction gas, for example, when a gas having a high CHF ₃ film deposition property and a low etching property is used, the reaction product tends to accumulate in the processing hole by etching as the processing by etching proceeds. A hole T as shown in FIG. 2 whose inner diameter becomes narrower toward the side is formed. In the figure, R indicates a resist.

On the other hand, as the second reaction gas, for example, when a CF ₄ -based gas having a high etching property and a low film deposition property is used, the semiconductor wafer W is shaved larger than the width of the hole of the mask as the processing by the etching proceeds. A hole T as shown in FIG. 3 is formed.

  Therefore, the angle of the inner wall of the hole T can be controlled by combining the first reactive gas and the second reactive gas.

  In the dry etching apparatus 10 configured as described above, etching is performed as follows. That is, Ar gas is introduced, and an electric field is generated in the chamber 20 by the power source 34 and the power source 37 to generate plasma. Next, etching is performed while repeating a cycle of introduction of first reaction gas, exhaust, introduction of second reaction gas, exhaust, introduction of first reaction gas,.

  Therefore, by alternately introducing the first reaction gas and the second reaction gas and proceeding with the processing by etching, the angle of the side wall of the hole or groove is controlled. Specifically, the flow rate of each gas is changed with time, and the ON / OFF time and flow rate of the gas are controlled with respect to time. Process shape can be controlled.

  FIG. 4 is an explanatory diagram showing an example of the timing of supplying the first reactive gas, supplying the second reactive gas, and exhausting. Exhaust is performed to remove the products generated during etching and to minimize the influence of the previous reaction gas. Furthermore, it is easy to stabilize the plasma by always introducing the rare gas into the chamber 20.

  By controlling the supply of the first reaction gas and the supply of the second reaction gas in this way, it is possible to form a hole T having an arbitrary shape as shown in FIG.

  As described above, according to the dry etching apparatus 10 according to the embodiment of the present invention, it is possible to arbitrarily control the shape of the hole by etching by controlling the amount of gas introduced during the etching process. .

  In the above-described embodiment, dry etching for manufacturing a semiconductor device is shown as an example. However, the present invention is not limited to dry etching, and can be applied to plasma ashing, plasma CVD, plasma sputtering, plasma cleaning, and the like. The present invention is applicable not only to semiconductor device processing, but also to thin film element processing on a liquid crystal panel or plasma generation and plasma processing for the purpose of painting a flat surface or curved surface.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The schematic diagram which shows the structure of the dry etching apparatus which concerns on one embodiment of this invention. Sectional drawing which shows an example of the etching shape by 1st reaction gas. Sectional drawing which shows an example of the etching shape by 2nd reaction gas. Explanatory drawing which shows the gas introduction timing in the dry etching apparatus. Sectional drawing which shows an example of the etching shape in the dry etching apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Chamber, 22 ... Exhaust pump, 30 ... Plasma production | generation mechanism, 40 ... Gas introduction mechanism, 41 ... 1st reaction gas supply part, 42 ... Gas flow rate adjustment valve, 43 ... 2nd reaction gas supply part, 44 ... Gas flow rate Adjustment valve, 45... Ar gas supply unit, 46... Gas flow adjustment valve, 48.

Claims (7)

An exhaust process for exhausting the chamber;
A first gas introduction step for introducing a first reaction gas into the chamber;
A first plasma generation step of generating plasma based on the first reaction gas in the chamber;
A second gas introduction step for introducing a second reaction gas into the chamber;
A plasma generation method comprising: a second plasma generation step for generating plasma based on the second reaction gas in the chamber. After the first plasma generation step, a first exhaust step for exhausting the chamber is performed.
2. The plasma generation method according to claim 1, wherein after the second plasma generation step, a second exhaust step of exhausting the inside of the chamber is performed.   The plasma generation method according to claim 1, wherein the first plasma generation step and the second plasma generation step are alternately performed.   The plasma generation method according to claim 1, wherein the first gas has a higher film deposition property than the second gas.   The plasma generation method according to claim 1, wherein the first gas has a lower etching property than the second gas.   The plasma generation method according to claim 1, further comprising a rare gas introduction step of introducing a rare gas different from the first and second gases into the chamber. A chamber;
An exhaust device for exhausting the chamber;
A first gas introduction unit connected to the chamber and introducing a first reaction gas from the outside;
A second gas introduction part connected to the chamber and introducing a second reaction gas from the outside;
A plasma generator for generating plasma in the chamber based on the first reaction gas or the second reaction gas;
A plasma generating system comprising: a control unit for controlling the timing of introducing the first and second reaction gases by the first and second gas introducing units and the timing of exhausting the chamber by the exhaust device. apparatus.

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