JP2000124139A - Plasma treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the temperature uniformity of a work by making the distances between surfaces at the mounting surface sides of refrigerant path chambers and a mounting surface different, depending on the radius position, in a vacuum chuck for holding the work on the mounting surface. SOLUTION: In a vacuum chuck for mounting a wafer 5 as a work, tubular refrigerant path chambers 22 are approximately concentrically disposed. The distance between the top end of the outermost refrigerant path chambers 22 and a water 5 mounting surface is set to be less than the distance between the top end of the inner refrigerant path chambers 22 and the wafer 5 mounting surface. The radial width of a section of the outermost refrigerant pass chambers 22 is set to be less than the sectional area of other each inner chamber 22. This increases the sectional area of the refrigerant path chambers 22 to decrease the flow velocity of a refrigerant, thereby avoiding reducing the heat transfer from the chamber 22 surface to the refrigerant. Thus the temperature rise is reduced at the peripheral part of the wafer 5 to uniformize the temperature distribution over the wafer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing heat from a workpiece or heating the workpiece during a process in a semiconductor process requiring temperature control of the workpiece such as a semiconductor wafer. The present invention relates to a plasma processing apparatus provided with a suction device.

[0002]

2. Description of the Related Art Conventionally, plasma CVD using reactive plasma has been used for processing an object to be processed such as a semiconductor wafer (hereinafter, referred to as "wafer") in a semiconductor manufacturing process.
(Chemical Vapor Deposition) apparatus, plasma etching apparatus and the like are used.

[0003] In various plasma processing apparatuses, an electrostatic suction apparatus is suitably used. This electrostatic adsorption device includes a conductor and an insulating film covering an adsorption portion of the object to be processed on the conductor, and applies a predetermined DC voltage between the conductor (electrode) and the object to be processed. An electrostatic force is generated between the two, and the object to be processed is adsorbed and held on the conductor.

[0004] Wafers receive heat during plasma processing, but it is necessary to control the temperature for proper processing. Therefore, a fluid such as a refrigerant is caused to flow in the electrostatic suction device, and the temperature of the suction device is adjusted to control the wafer at a desired temperature.

The radius of the electrostatic attraction device of the plasma processing apparatus is manufactured to be about 1 mm smaller than the wafer radius. This is to prevent the corners of the electrostatic chuck from being directly exposed to the plasma and to protect the surface of this portion from plasma irradiation.

For the above reasons, the wafer protrudes from the electrostatic attraction device, and the portion does not come into contact with the surface of the electrostatic attraction device or the heat transfer gas flowing on the surface of the electrostatic attraction device. Tend to be higher than other regions.

[0007]

As described above, in order to improve the temperature uniformity of the wafer, the temperature of the outer peripheral portion of the electrostatic attraction device needs to be lower than that of other regions. For that purpose, it is considered effective to increase the wet edge area (the contact area between the refrigerant and the electrostatic adsorption device) of the refrigerant passage chamber in the electrostatic adsorption device at the outer peripheral portion. However, as disclosed in Japanese Patent Application Laid-Open No. 9-205133, in order to reduce the deformation of the wafer when the wafer is detached from the electrostatic chucking device, the pusher pin is required to be positioned at 60 to 80% of the wafer radius. It is difficult to provide a coolant passage having a large wetted edge area on the outer peripheral portion due to the presence of the pusher pin at that position.

Recently, ultra-fine processing technology is required due to the high integration of semiconductors, and a higher degree of substrate temperature control than in the past is required. In addition, the substrate to be processed is 8 inches to 1 inch.
As the diameter increases to 2 inches, it becomes difficult to maintain plasma uniformity over a wide area, and the temperature distribution within the wafer surface may increase.

[0009]

In a plasma processing apparatus which can hold an object to be processed on a mounting surface and has a suction device having a chamber for flowing a fluid therein, the plasma processing apparatus has a chamber on the mounting surface side. A plasma processing apparatus is characterized in that the distance between the surface and the mounting surface is different depending on the radial position.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 illustrates a first embodiment of the present invention, and is an example in which the present invention is applied to a magnetic field microwave plasma CVD apparatus. In this figure, reference numeral 4 denotes an electrostatic suction device, a side sectional view of which is shown in FIG. 2, and FIG. 3 is a plan sectional view of FIG.

A quartz lid 2 is set in an air space 1, and a wafer 5 is fixed in a vacuum processing chamber 3 formed by using a suction device 4. Subsequently, a processing gas 7 is introduced into the vacuum processing chamber 3 from a suction system (not shown) through the nozzle 6.
Is introduced. The processing gas 7 is turned into a plasma 12 by the interaction between the microwave 9 introduced through the waveguide 8 and the coil 11 attached around the discharge tube 10. The processing (here, the film formation processing) is performed by exposing the wafer 5 to the plasma 12, and in particular, the high frequency power supply 1 controls the film formation state by controlling the incidence of ions.
3. The DC power supply 14 is connected to the electrodes, and the wafer 5 is reliably attracted by generating an electrostatic force.
Reference numeral 15 denotes a switch for controlling on / off of the DC power supply. Reference numeral 16 denotes an exhaust port for excess processing gas and reaction products, which is connected to a vacuum pump (not shown).

FIG. 2 shows how the processing wafer 5 is actually sucked. Since ions and radicals are incident on the wafer 5 during the processing from the plasma 12 and the temperature rises, the suction device 4 is cooled as described above to realize an appropriate film forming process. Is performed in a vacuum, the heat transfer efficiency is low, and the cooling efficiency of the wafer 5 is poor. Therefore, in the present embodiment, gas holes 19 are provided in the lower block 17 and the upper block 18, and a heat transfer gas such as helium (He) flows on the back surface of the wafer 5 to increase heat transfer efficiency. Although not shown here, an uneven shape is formed on the surface of the mounting surface, so that the heat transfer gas can be evenly distributed on the back surface of the wafer 5. In addition, reference numeral 20 denotes a susceptor for protecting the upper block 18 from the plasma 12, and reference numeral 21 denotes a thermometer for monitoring the temperature of the wafer 5 being processed.

The upper block 18 has a tubular fluid passage chamber 2.
2, a cooling device (not shown) supplies a refrigerant from a supply port 23 by a cooling device connected to the outside, passes through a fluid passage chamber 22, discharges from a discharge port 24, and outputs a temperature of the adsorption device 4. Is controlled to control the temperature of the wafer 5 being processed. The upper block 18 and the lower block 17 are fixed by bolts 25.

Reference numeral 26 denotes a pusher pin which lifts the processed wafer 5 and transfers it to a transfer arm (not shown).

In this embodiment, as shown in FIGS. 2 and 3, the tubular fluid passage chambers 22 are arranged substantially concentrically, and the distance between the upper end of the outermost fluid passage chamber and the mounting surface of the wafer 5 is set as follows. It is smaller than the inner fluid passage chamber. At this time, the radial width of the cross section of the outermost fluid passage chamber is smaller than the cross sectional area of each of the other circumferences. This is because it is difficult to secure a flow path having a large width in the radial direction due to the presence of the pusher pin 26 and the bolt 25 on the outer peripheral portion of the suction device 4, and the flow velocity of the fluid decreases due to an increase in the cross-sectional area of the fluid passage chamber. This is to prevent heat transfer from the surface of the fluid passage chamber 22 to the fluid from being reduced. Here, the upper end of the fluid passage chamber 22 refers to the fluid passage chamber 22 when the suction device 4 is cut in a cross section as shown in FIG.
Means the portion closest to the mounting surface of the wafer 5 in each circumference.

The cross-sectional shape of the tubular fluid passage chamber 22 as shown in the first embodiment may be a shape other than a square such as a circle or a triangle.

FIG. 4 shows a wafer temperature distribution when a 5000-W heat is input to a 12-inch wafer (diameter 300 mm) according to the conventional example and the first embodiment of the present invention. The temperature difference between the conventional electrostatic chuck and the embodiment of the present invention is 1 unit.
6.2 ° C and 5.8 ° C. In the conventional electrostatic attraction device, the temperature rises at the outer peripheral portion of the wafer. However, according to the embodiment of the present invention, the temperature rise at the outer peripheral portion is small, and the temperature distribution is more uniform than the conventional example. I understand.
The waveform of the temperature distribution of the wafer is affected by the shape of the irregularities on the surface of the electrostatic chuck. That is, the temperature of the wafer drops at the contact portion between the wafer and the surface of the electrostatic chuck.

FIGS. 5 and 6 are a side sectional view and a plan view showing a second embodiment of the present invention. In the first embodiment, the fluid passage chamber is tubular, but in this embodiment, it is a disk-shaped space. Even in such a case, by making the distance between the upper end of the fluid passage chamber and the wafer mounting surface in the outer peripheral portion smaller than that in the inner peripheral portion, it is possible to suppress the temperature rise in the outer peripheral portion of the wafer, The internal temperature distribution can be made more uniform. In the above embodiment, the refrigerant is used as the fluid. However, when it is required to raise the temperature of the electrostatic adsorption device, a heat medium may be used as the fluid.

In the first and second embodiments, the distance between the upper end of the fluid passage chamber and the mounting surface of the object to be processed is smaller than the other area in the outer peripheral portion of the electrostatic suction device. The change is not limited to the outer peripheral portion. For example, if the wafer temperature becomes high in the center due to non-uniformity of the plasma, if the distance between the upper end of the fluid passage chamber and the mounting surface of the processing object is made smaller than the other area in the center of the electrostatic chuck, The temperature rise of the wafer at the center can be suppressed.

[0020]

As described above, according to the present invention, in a plasma processing apparatus using an adsorption device, the temperature uniformity of an object to be processed such as a semiconductor wafer can be improved, and excellent processing can be performed on the object to be processed. It is possible to provide a plasma processing apparatus which can perform the plasma processing.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a plasma processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of an electrostatic attraction device used in the plasma processing apparatus according to the first embodiment of the present invention.

FIG. 3 is a plan view of an electrostatic chuck used in the plasma processing apparatus according to the first embodiment of the present invention.

FIG. 4 is a graph showing a temperature distribution of a wafer according to the first embodiment of the present invention.

FIG. 5 is a side sectional view of an electrostatic chuck used in a plasma processing apparatus according to a second embodiment of the present invention.

FIG. 6 is a plan view of an electrostatic chuck used in a plasma processing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

3 vacuum processing chamber, 5 wafer, 6 nozzle, 7 processing gas, 8 waveguide, 10 discharge tube, 17 lower block,
18: upper block, 19: gas hole, 21: thermometer,
22: fluid passage chamber, 23: supply port, 24: discharge port, 25
... bolts, 26 ... pusher pins.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Eiji Setoyama, 1-1-1, Kokubuncho, Hitachi, Ibaraki Prefecture Inside Kokubu Plant, Hitachi, Ltd. (72) Koji Ishiguro, 1-1-1, Kokubuncho, Hitachi, Ibaraki No. 1 F-term in Kokubu Plant of Hitachi, Ltd. (reference) 4K030 CA04 CA12 FA01 GA02 HA06 JA03 KA08 KA26 5F031 HA08 HA16 HA33 HA37 HA38 HA39 MA28 MA32 5F045 AA10 EH20 EJ03 EJ10 EK21 EK27 EM05

Claims (1)

[Claims] 1. A plasma processing apparatus having an adsorption device capable of holding an object to be processed on a mounting surface and having a chamber for flowing a fluid therein, wherein the surface on the mounting surface side of the chamber and the surface of the plasma processing apparatus. A plasma processing apparatus, wherein the distance from the mounting surface varies depending on the radial position.