JPH1154482A - Semiconductor device manufacturing method and apparatus, and work processing method - Google Patents

Abstract

(57) [Problem] To perform a constant and uniform predetermined process even for a large-diameter work affected by temperature conditions. SOLUTION: A lower electrode 3 and an upper electrode 4 opposed to the lower electrode 3 are provided in a processing vessel 2, and an etching processing gas is supplied while a wafer W is mounted on the lower electrode 3. Plasma is generated in the processing chamber 1 by supplying power from the supply device 7 into the processing chamber 1 and applying power from the high-frequency oscillator 5 to the electrodes 3 and 4. The processing container 2 is provided with an infrared temperature sensor 20 for detecting the distribution of the surface temperature of the wafer W during the etching process. The lower electrode 3 is divided into a plurality of electrode forming portions,
The temperature of each electrode forming portion is determined by the infrared temperature sensor 20.
Is independently controlled based on signals from

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for processing a work, for example, a technique useful for applying a semiconductor wafer as a work to dry etching of the work.

[0002]

2. Description of the Related Art For example, when a semiconductor device is manufactured, a semiconductor wafer (hereinafter, simply referred to as a wafer) is processed by a CVD process for forming a thin film of a desired substance on a surface of the wafer, or a fine process on the wafer. There are an etching process for forming a circuit pattern and an ashing process for removing a resist remaining on a wafer after the etching process. For the etching process, for example, a dry etching process technology using a dry plasma processing technology is applied. This technology is a technology in which plasma discharge is performed under reduced pressure of a reactive gas, so that ions that cannot be stably obtained at normal pressure are removed. This is a technique for generating a reactive species such as a radical and a radical to promote a predetermined chemical reaction to process the wafer.

[0003] As a dry etching technique, for example, June 20, 1993, Press Journal, Inc., June 1993, "Monthly Semiconductor World" P146
To P152, there are various types such as a barrel type plasma etching apparatus, a reactive ion etching apparatus, and a microwave plasma etching apparatus.

[0004]

As a dry etching apparatus, there is a dry etching apparatus having a vacuum chamber in which a processing chamber is formed, in which a lower electrode and an upper electrode are incorporated in the vacuum chamber. A wafer as a workpiece as a workpiece is held. In such a dry etching apparatus, characteristics such as an etch rate and its uniformity, a selectivity with an underlayer or a photoresist (mask material), an etch profile, and the like change depending on a temperature condition of a wafer. Therefore, as the diameter of a wafer increases and the pattern becomes finer, the importance of controlling the wafer temperature in the etching process is increasing.

[0005] The present inventors have studied the plasma processing technology. The following is a technique studied by the present inventors, and the outline is as follows.

That is, in a dry etching apparatus utilizing a plasma processing technique, a coolant such as cooling water is circulated through a lower electrode or a work support, or an inert gas is used as a cooling gas for a wafer on the work support. Attempts have been made to control the temperature of the wafer during the etching process by spraying or a combination of both. Therefore, in consideration of the difference between the etch characteristics of the central portion and the peripheral portion of the wafer in advance, a dry etching apparatus that divides the lower electrode into a plurality of regions and sets each portion to a different temperature was studied.

However, in this type, the temperature is controlled so as to always obtain a constant and uniform etch characteristic even under various etching conditions such as high-frequency power applied to both electrodes, processing time and pressure of cooling gas. It has been found that it is difficult to control the temperature, and it is particularly difficult to suitably control the temperature in processing such as etching of a large-diameter wafer.

An object of the present invention is to make it possible to perform a uniform and uniform processing even on a large-diameter work.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, in the method of manufacturing a semiconductor device according to the present invention, the semiconductor wafer is processed in a processing chamber provided with a work support for supporting the semiconductor wafer, and a distribution of a surface temperature of the semiconductor wafer during the processing. And controlling the temperature of the work support table for each of a plurality of regions during the processing based on the distribution of the surface temperature of the semiconductor wafer, and controlling the surface temperature for each of the plurality of regions during the processing of the semiconductor wafer. Characterized in that it can be controlled to

Further, the semiconductor device manufacturing apparatus of the present invention comprises:
A processing chamber in which a processing chamber is formed and a work supporting table for supporting the semiconductor wafer is provided, a temperature detecting means for detecting a surface temperature distribution of the semiconductor wafer when processing the semiconductor wafer, A plurality of temperature control means for separately controlling the temperature for each of a plurality of regions, and a control means for controlling the operation of each of the temperature control means when processing a semiconductor wafer based on a signal from the temperature detection means. And wherein the surface temperature of the semiconductor wafer can be controlled for each of a plurality of regions during processing. By generating plasma in the processing chamber, dry etching can be performed on the semiconductor wafer.

In the present invention, the temperature distribution over the entire surface of the semiconductor wafer is detected by the temperature sensor, and the temperature of the work support is controlled independently for each of the plurality of regions based on the detection result. Therefore, the processing of the entire semiconductor wafer can be made uniform, and the film thickness,
Processing characteristics such as an etch rate can be processed to optimal characteristics for the entire semiconductor wafer.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a view showing a dry etching apparatus according to an embodiment of the present invention. The apparatus has a vacuum vessel or processing vessel 2 in which a reaction chamber or processing chamber 1 is formed. A lower electrode 3 as a work support is provided in the processing vessel 2, and an upper electrode 4 is provided to face the work support 3. The wafer W, which is a work, is mounted on the work support 3.

A high frequency oscillator 5 is connected to the lower electrode 3 and the upper electrode 4 to supply power of a predetermined frequency to the lower electrode 3 and the upper electrode 4. 4 is controlled to an arbitrary value.

The processing chamber 2 includes a processing chamber 1 and a gas supply device 7.
A gas supply path 8 is connected between the processing chamber 1 and a predetermined processing gas for etching processing from the gas supply device 7.
Supplied within. The gas supply path 7 is provided with a mass flow controller, that is, a flow rate control device 9 for controlling the flow rate of the processing gas.

The processing chamber 2 includes a processing chamber 1 and a vacuum pump 11.
The vacuum pump 11 is connected to the processing chamber 1. The vacuum pump 11 operates to keep the inside of the processing chamber 1 at a predetermined degree of vacuum. The evacuation path 12 is provided with a pressure control device 13 for controlling the pressure in the processing chamber 1.

FIG. 2 is a partially cutaway perspective view showing the lower electrode 3 shown in FIG. 1 in an enlarged scale. The lower electrode 3 is located at the center of the columnar electrode forming portion 3a and outside thereof. It has three regions: a ring-shaped electrode forming portion 3b and a ring-shaped electrode forming portion 3c located outside and having a larger diameter than the electrode forming portion 3b.

A loop-shaped guide passage 14a is formed in the electrode forming portion 3a on the surface side thereof, and a coolant such as cooling water is provided at one end of the guide passage 14a. Is connected to a supply channel 15a for supplying
The other end is connected to a discharge channel 16a for discharging the refrigerant in the guide channel 14a to the outside. Similarly, the other two
Guide passages 14b, 14 are provided in the two electrode forming portions 3b, 3c.
c are respectively formed, supply flow paths 15b and 15c are connected to one end of each guide flow path, and discharge flow paths 16b and 16c are connected to the other end.

A wafer W is fixed on the surface of the lower electrode 3 by an electrostatic chuck or a mechanical chuck, and a gas flow having an opening 17 facing the wafer W is formed on the surface of the lower electrode 3. A passage 18 is formed, and an inert gas such as helium gas is supplied to the back surface of the wafer W as a cooling gas through the gas passage 18.

As shown in FIG. 3, the gas flow paths 18 shown in FIG. 2 are provided in each of the three electrode forming portions 3a to 3c, and correspond to the respective gas flow paths 18. An opening 17 is formed in each of the three electrode forming portions 3a to 3c. The positions of the openings 17 formed in the respective electrode forming portions 3a to 3c are formed at desired positions according to processing conditions and the like. Further, an annular or radial gas guide groove may be formed in the lower electrode 3 so as to communicate with the respective openings 17.

In order to detect the surface temperature of the wafer W, the processing container 2 is provided with an infrared temperature sensor 20.
The infrared temperature sensor 20 detects the temperature distribution on the entire surface of the wafer W, and can detect the surface temperature of the wafer W for each of a plurality of regions. The infrared temperature sensor 20 is connected to a control unit 21, and a detection signal from the infrared temperature sensor 20 is sent to the control unit 21 as shown in FIG. 22. The temperature control device 22 controls the flow rate and temperature of the refrigerant, and independently controls the flow rate and pressure of the cooling gas for each gas flow path 18.

It should be noted that the number of gas passages 18 is not one gas passage for each electrode forming portion as shown in the figure, but a plurality of gas passages 18 may be provided in one electrode forming portion. good.

As shown in FIG. 3, a gas supply source 23 is connected to each of the three gas channels 18 and a flow control device for controlling the flow rate of the cooling gas flowing inside each of the gas channels 18. A pressure control device 22b for controlling the pressure of the cooling gas is provided. Each gas flow path 18 is provided with a pressure sensor 24 for detecting the pressure of the cooling gas therein, and a detection signal from the pressure sensor 24 is sent to the control unit 21.

The pressure of the cooling gas in each gas flow path 18 changes in accordance with the degree of adhesion of the wafer W to the surface of the lower electrode 3, and the lower the degree of adhesion, the lower the pressure. The pressure control device 22b is feedback-controlled based on the detection signal from the sensor 24, and the pressure of the cooling gas is set to an optimum pressure value.

Each of the supply channels 15a to 15c is connected to a refrigerant supply device 22c, and the flow rate and the temperature of the refrigerant supplied from each supply channel to the guide channels 14a to 14c are independently controlled. It has become. The coolant supply device 22c constitutes a chiller control device for cooling the wafer W via the lower electrode 3. The refrigerant discharged from each of the discharge channels 16a to 16c is returned to the refrigerant supply device 22c and circulated to the guide channel to be supplied. The temperature control device 22 shown in FIG. 1 is constituted by the flow control device 22a, the pressure control device 22b, and the refrigerant supply device 22c.

The procedure for etching the wafer W by using such a dry etching apparatus will be described. The wafer W carried into the processing vessel 2 is placed on the surface of the lower electrode 3 and is lowered by an electrostatic chuck or the like. It is fixed to the electrode 3. In this state, a desired etching gas is supplied from the gas supply device 7 shown in FIG. 1 to the processing chamber 1 of the processing container 2 at a desired flow rate via the flow rate control device 9.
At the same time, the inside of the processing chamber 1 is evacuated by the vacuum pump 11 and the processing chamber 1 is
Is controlled to a desired pressure. Furthermore, the wafer W is etched by applying high frequency power from the high frequency oscillator 5 to the upper electrode 4 and the lower electrode 3 to generate plasma.

Although the surface temperature of the wafer W changes due to the heat of the plasma, the distribution of the entire surface temperature of the wafer W is detected by the infrared temperature sensor 20 and the detected value is sent to the control unit 21. Based on this detection signal, the pressure and flow rate of the cooling gas are controlled so that the processing characteristics over the entire surface of the wafer W are uniform, and the temperature and flow rate of the coolant are adjusted for the three electrode forming portions 3a to 3c. Controlled separately.

As described above, since the respective temperatures can be controlled for each of the three electrode forming portions 3a to 3c concentrically divided, the processing characteristics of the wafer W become a desired value, and the etching of the wafer W is performed. The characteristics will be kept constant and uniform. Thereby, even if the wafer W has a large diameter,
The precision of the etching process is dramatically improved. Although the lower electrode 3 including the three electrode forming portions 3a to 3c is physically integrated with all the electrode forming portions in the illustrated case, the temperature of each of the electrode forming portions is reduced. Since it can be controlled independently, it is divided into three.

In the illustrated embodiment, the guide flow paths 1 formed in each of the three electrode forming portions 3a to 3c are provided.
4a to 14c are formed in a loop shape in a line in the circumferential direction, but may be formed in a spiral shape as a guide flow path having a plurality of turns, and the number of turns is made different depending on the position of the electrode forming portion. May be. Further, the guide flow path may be formed in a lattice shape.

Also, in the case shown in FIG.
Although it is formed by one electrode forming portion, it may be formed by three or more electrode forming portions.

FIGS. 4A and 4B are views showing a lower electrode 3 according to another embodiment of the present invention, wherein the lower electrode 3 of the above embodiment is formed in a concentric three electrode forming portion. 3
a to 3c, in the case shown in FIG. 4A, eight electrode forming portions 3d are provided radially,
Each of the electrode forming portions 3d is formed by a fan-shaped region when viewed from the surface. However, the number of the radial electrode forming portions 3d is not limited to the number of the illustrated regions, but may be any number.

In the case shown in FIG. 4 (B), the lower electrode 3 is composed of a large number of electrode forming portions 3e which form one area in a grid-like portion.
In this case as well, the number of regions of the electrode forming portion 3e can be arbitrarily set.

As shown in FIG. 4A, a thermocouple type temperature sensor 21a is incorporated in each electrode forming portion 3e, and in the case shown in FIG.
, The temperature of the surface of the wafer W is detected in a non-contact manner, while the temperature of the electrode forming portion 3e is measured to estimate the surface temperature of the wafer W.
The number of thermocouple temperature sensors 21a incorporated in each electrode forming portion 3e can be any number. However, a thermocouple may be incorporated into the lower electrode 3 of the type shown in FIGS. 2 and 3 as a temperature sensor.

As described above, the invention made by the inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the invention. Needless to say,

For example, in the case shown, the plurality of electrode forming portions 3a to 3e are physically integrated, and can be controlled independently of each other, so that they are divided into three regions. However, it is also possible to form each lower electrode 3 by combining the respective electrode forming portions as physically separated members and combining them. That is, as long as the temperature can be controlled independently for each predetermined region, the entire lower electrode 3 may be configured as an integrated structure or a separated structure.

In the above description, the case where the invention made by the present inventor is mainly applied to the dry etching processing technique, which is the field of application, has been described. However, the present invention is not limited to this. The present invention can be applied to any case where the workpiece is processed in the processing chamber by the plasma as in the above.

[0039]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1) The temperature distribution on the entire surface of the work is detected by the temperature sensor, and the temperature of the work support is independently controlled for each of the plurality of regions based on the detection result. The whole can be processed under optimal processing conditions to obtain a high quality work.

(2) When a dry etching process is performed on a workpiece as a semiconductor wafer, even if the etch characteristics differ depending on the position of the semiconductor wafer based on factors other than the temperature, the temperature is set to a plurality of lower electrodes. By independently controlling the regions, the etch characteristics can be improved.

(3) When dry etching is performed,
The etching process can be performed with a constant and uniform etch characteristic at all times while suppressing the variation in the temperature distribution of the entire wafer.

(4) As a result, the yield of the dry etching of the semiconductor wafer can be improved and stabilized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic structure of a dry etching apparatus according to an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing a lower electrode shown in FIG. 1 in an enlarged manner.

FIG. 3 is a schematic diagram showing a lower electrode shown in FIG. 1 and temperature control means for cooling the lower electrode.

FIGS. 4A and 4B are perspective views each showing a modification of the lower electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing chamber 2 Processing container 3 Lower electrode (work support base) 4 Upper electrode 5 High frequency oscillator 6 Power control unit 7 Gas supply device 8 Gas supply path 9 Flow control apparatus 11 Vacuum pump 12 Vacuum exhaust path 13 Pressure control apparatuses 14a to 14c Guide flow path 15a to 15c Supply flow path 16a to 16c Discharge flow path 17 Opening 18 Gas flow path 20 Infrared temperature sensor 21a Thermocouple temperature sensor 22 Temperature control device 22a Flow control device 22b Pressure control device 22c Refrigerant supply device 23 Gas supply Source 24 pressure sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naonori Wada 5-2-1, Josuihonmachi, Kodaira-shi, Tokyo Inside Semiconductor Division, Hitachi, Ltd. (72) Inventor Shizuo Kobayashi Gojosomi, Kosumi-shi, Tokyo 20-1 Chome, Semiconductor Division, Hitachi, Ltd. (72) Inventor Tadashi Chikawahara 5-2-1, Kamimizu Honcho, Kodaira City, Tokyo Corporation, Semiconductor Division, Hitachi, Ltd. (72) Inventor Yoichi Hiwa Hitachi, Ltd. Semiconductor Division, 5-2-1, Josuihoncho, Kodaira City, Tokyo (72) Inventor Takao Fujiwara, Semiconductors Division, 5-2-1, Josuihoncho, Kodaira, Tokyo ( 72) Inventor Yoshio Sato 5-22-1, Josuihoncho, Kodaira-shi, Tokyo Inside Hitachi Microcomputer System Co., Ltd.

Claims (7)

[Claims] A processing step of processing the semiconductor wafer in a processing chamber provided with a work support supporting the semiconductor wafer; and a temperature detecting step of detecting a distribution of a surface temperature of the semiconductor wafer during the processing step. And a step of controlling the temperature of the work support table for each of a plurality of regions in the processing step based on the distribution of the surface temperature of the semiconductor wafer. A method for manufacturing a semiconductor device, characterized in that control can be performed for each of a plurality of regions. 2. The method of manufacturing a semiconductor device according to claim 1, wherein an etching gas is supplied into the processing chamber,
The work support is a lower electrode, and the semiconductor wafer is dry-etched by applying high-frequency power to the upper electrode and the lower electrode opposed thereto to generate plasma in the processing chamber. A method for manufacturing a semiconductor device, comprising: 3. The method of manufacturing a semiconductor device according to claim 1, wherein the distribution of the surface temperature of the semiconductor wafer is detected in a non-contact manner by temperature detecting means such as an infrared temperature sensor. A method for manufacturing a semiconductor device. 4. A processing container in which a processing chamber is formed and a work support table for supporting a semiconductor wafer is provided; a temperature detecting means for detecting a distribution of a surface temperature of the semiconductor wafer when processing the semiconductor wafer; A plurality of temperature control means for separately controlling the temperature of the work support table for each of a plurality of regions; and, based on a signal from the temperature detection means, controlling operation of each of the temperature control means when processing a semiconductor wafer. And a control means for controlling a surface temperature of each of the plurality of regions during processing of the semiconductor wafer. 5. An apparatus for manufacturing a semiconductor device according to claim 4, wherein: a processing gas supply means for supplying an etching processing gas into the processing chamber; and a lower electrode and an upper electrode formed by the work support. And a plasma generating means for generating plasma in the processing chamber, wherein the semiconductor wafer is subjected to a dry etching process. 6. An apparatus for manufacturing a semiconductor device according to claim 4, wherein said temperature detecting means is an infrared temperature sensor. 7. A processing step of processing the work in a processing chamber having a work support table for supporting the work, a temperature detecting step of detecting a distribution of a surface temperature of the work at the time of the processing step, Controlling the temperature of the work support base for each of a plurality of regions at the time of the processing based on the distribution of surface temperatures, and controlling the surface temperature at the time of processing the work for each of the plurality of regions. A method for processing a workpiece, characterized in that: