JPS62281423A - Method and device for dry etching - Google Patents

Abstract

PURPOSE:To suppress slowing down of an etching rate in an initial stage and improve an average etching rate by starting an etching treatment using plasmas after heating a sample and keeping a temperature of the sample at a prescribed temperature during a period of the etching treatment. CONSTITUTION:An etching treatment is started by heating a sample 50 using plasmas and keeps a temperature of the sample 50 at a prescribed temperature during a period of etching treatment. The plasmas are generated in a container 10 whose inside is maintained in a vacuum. A device, which performs the etching treatment of the sample 50 that is put on a electrode 30 in the container 10, is provided with heat source means 60 which heat or cool an electrode 30, for example, a circulating heat exchanger, temperature detecting means 70 which detect a temperature of electrode 30, and control means 80, for example, a microcomputer controlling the temperature of electrode 30 at a preset temperature through the heat source means 60, thereby comparing a temperature of electrode 30 preset according to a given temperature of the sample 50 during the period of etching treatment with the temperature of electrode 30 detected by the temperature detecting means 70.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a dry etching method and apparatus;
The present invention relates to a dry etching method and apparatus suitable for etching a sample such as a semiconductor element substrate (hereinafter abbreviated as "substrate") using plasma.

[Conventional technology]

Conventionally, in a dry etching technique such as that described in Japanese Unexamined Patent Publication No. 57-66642, an electrode on which a substrate is placed is cooled by water cooling, and the substrate is cooled through the cooled electrode during the etching process. Ru.

However, in such conventional techniques, the substrate is cooled during the etching process to prevent deterioration of the resist, and no consideration is given to the temperature dependence of the etching rate.

[Problem that the invention seeks to solve]

The above conventional technique does not take into account the temperature dependence of the etching rate, and has the problem that the etching rate is low at the initial stage of etching because the temperature of the sample is low, and the average etching rate is low. In particular, since the etching time is short in an etching apparatus that processes each sample one by one, the average etching speed varies greatly depending on the etching speed at the initial stage of etching. In addition, such problems
This phenomenon is particularly noticeable when etching is performed with a sample placed on the ground electrode.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dry etching method and apparatus that takes into account the temperature dependence of etching rate, suppresses a decrease in etching rate at the initial stage of etching, and improves the average etching rate.

[Failure to solve the problem]

The above object is a dry etching method in which a sample is etched with plasma, the sample is heated to start the etching process, and the temperature of the sample is maintained at a predetermined temperature during the etching process; In addition, a dry etching device is a device that generates plasma in a container kept in a vacuum and etches a sample placed on an electrode provided in the container using the plasma, and a heat source that heats and cools the electrode. a temperature detection means for detecting the temperature of the electrode; a temperature of the electrode preset corresponding to a predetermined temperature of the sample during the etching process; and a temperature of the electrode detected by the temperature detection means. This can be achieved by comprising a control means for controlling the temperature of the electrode to a preset temperature via the heat source means.

[For production]

By raising the temperature of the sample at the start of the etching process, the etching rate at the initial stage of etching increases.Also, by lowering the temperature of the electrode on which the sample is installed as the etching time progresses, the temperature of the sample is maintained at a predetermined temperature. The resist is maintained without deterioration (the etching process progresses. As a result, the decrease in etching speed at the initial stage of etching is eliminated and the average etching speed is improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, electrodes 20 and 30 are provided in a vacuum vessel 10 in parallel with each other and in this case facing each other in the vertical direction. In this case, the electrode force is, for example, at a frequency of 13
．． Connected to 56 MHz RF power off. The electrode force is at ground potential, and the sample, e.g.
It is large enough to install one. Further, a heat medium circulation channel (not shown) is formed inside the electrode. In this case, the heat source means is a circulating heat exchanger ω, which has a function of adjusting the temperature of the heat medium. Note that the heat medium whose temperature has been adjusted in the circulating heat exchanger ω is
The heat medium supplied to the heat medium circulation flow path and discharged from the heat medium circulation flow path is returned to the circulation heat exchanger area.

In this case, the temperature sensing means is a temperature measuring device 70, which is not affected by high frequency noise, for example, a temperature measuring device using a fluorescent substance in the sensor and an optical fiber cable in the probe 1. A measuring device is used. The control means in this case is a microcomputer. To the microcomputer master.

'II! which is preset corresponding to the predetermined temperature between the substrates during the etching process. The temperature of the pole (9) (hereinafter abbreviated as set temperature) is input in advance. The temperature of the electrode force measured by the temperature measuring device 70 (hereinafter abbreviated as actual MJ temperature) is inputted into the microcomputer. The microcomputer compares the set temperature input in advance with the actual measured temperature input from the temperature measuring device 70, and circulates a control signal for heat exchange so that the temperature of the electrode I reaches the set temperature according to the temperature difference. It has a function to output between devices. Is the circulation heat exchanger receiving the control signal? ! In the A device ω, the temperature of the heat medium is adjusted so that the temperature of the electrode (material) becomes the set temperature.

In FIG. 1, the microcomputer includes, for example, a second
A set temperature, an example of which is shown in the figure, is input in advance. Second
In the figure, the temperature between the substrates at the start of the etching process is 100°C.
The set temperature is also 100°C to ensure that. During the etching process (as the etching time passes, the temperature between the substrates tends to rise from 100°C as a starting point. Therefore, the set temperature needs to be lowered from 100°C as a starting point. During this period, the rise in temperature between the substrates is suppressed and the temperature is maintained at about 120℃.Here, the temperature between the substrates is 100℃, 120℃.
The temperature of about 0.degree. C. means that the resist does not change in quality.

In FIG. 1, the inside of a vacuum container 10 is evacuated to a predetermined pressure by the operation of a vacuum evacuation device it (not shown). A predetermined flow rate of etching gas is introduced into the vacuum container 10, which has been evacuated to a predetermined pressure, from an etching gas supply channel (not shown). A part of the etching gas introduced into the vacuum container 10 is exhausted to the outside of the vacuum container 10 by the operating vacuum evacuation device.
The etching pressure inside is adjusted to a predetermined etching pressure. On the other hand, 1!
The temperature of the extreme temperature is measured by a temperature measuring device 70 . If the measured temperature is lower than the set temperature of 100°C shown in Figure 2, the control signal from the microcomputer will control the heating medium to a temperature that will bring the temperature between the electrodes to 100°C between the circulating heat exchangers. After heating and raising the temperature, electricity! f! 30 heat medium circulation channels. As a result, the temperature between the electrodes is controlled to 100°C, and at the same time, the temperature between the substrates is raised to l 00 'C.

Thereafter, power is applied to the electrode I from the RF1 source. As a result, t! Glow discharge occurs between the L poles 20 and 30, and the etching gas is turned into plasma.

This plasma starts etching the surface of the substrate to be processed. During this etching process, the temperature between the electrodes is continuously or intermittently measured by a temperature measuring device 70. This measured temperature is input into the microcomputer each time and compared with the set temperature shown in FIG. 2, which is set in summer and corresponds to that time. Based on the comparison results, the microcomputer department recommends each time,
A control signal is output to the circulating heat exchanger stamp. As a result, the temperature of the electrode J is controlled to the set temperature shown in FIG. 2, whereby the temperature of the substrate is maintained at about 120 DEG C. during the etching process.

In this example, the temperature of the substrate at the start of the etching process was set to 1
Since the temperature is as high as 00° C., a decrease in the etching rate at the initial stage of the etching process is suppressed, and therefore the average etching rate is improved.

In addition, since the temperature of the substrate at the start of the etching process is controlled to 100°C, a temperature that does not change the quality of the resist,
Etching speed at the initial stage of etching processing can be improved while maintaining high pattern accuracy. In a dry etching apparatus that processes each substrate one by one, the etching processing time can be further shortened by one point, and high efficiency can be achieved.

In addition, in this example, RF with a frequency of 13.56 MHz
The explanation was given using an etching device that uses a power supply as an example.
Similar effects can be obtained with other devices, such as etching devices that use microwaves. Furthermore, for example,
Similar effects can be obtained depending on the conditions when etching the substrate by placing it on the @ pole connected to the RFg source, or when applying a bias voltage to the substrate using an etching device using microwaves.

〔Effect of the invention〕

According to the present invention, since it is possible to suppress a decrease in the etching rate at the initial stage of etching, there is an effect that the average etching rate can be improved.

[Brief explanation of drawings]

FIG. 2 is a block diagram of a dry etching apparatus according to an embodiment of the present invention, and FIG. 2 is a relationship diagram between the set temperature input in advance to the microcomputer of the apparatus shown in FIG. 1, substrate temperature, and etching time. It is.

Claims (1)

[Claims] 1. A method for etching a sample using plasma, characterized by heating the sample to start the etching process, and maintaining the temperature of the sample at a predetermined temperature during the etching process. Dry etching method. 2. In an apparatus for generating plasma in a container kept in vacuum and etching a sample placed on an electrode provided in the container using the plasma, a heat source means for heating and cooling the electrode; A temperature detection means for detecting the temperature compares the temperature of the electrode detected by the temperature detection means with the temperature of the electrode set in advance corresponding to a predetermined temperature of the sample during the etching process, and A dry etching apparatus comprising: control means for controlling the temperature of the electrode to a preset temperature via means.