JP3617137B2 - Substrate electrode - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate electrode such as a sputtering apparatus.
When a thin workpiece substrate is attached to the substrate electrode facing away from the target and metal is deposited on the surface of the workpiece substrate to form a film, the workpiece substrate with poor flatness due to warpage or undulation is in close contact with the substrate electrode. Insufficient heat causes unevenness in heat conduction from the substrate electrode, making it difficult to control the temperature of the substrate to be processed. Therefore, there is a demand for a substrate electrode structure that is uniform and has good heat conduction efficiency.
[0002]
[Prior art]
FIG. 5 illustrates a direct current sputtering apparatus. As shown in the figure, the substrate electrode 100 and the target 2 are separated from each other in a vacuum chamber 7 that is evacuated by a vacuum pump 15 and filled with a diluted Ar gas, and the substrate electrode 100 and the target 2 are separated by a high-voltage DC power source 3. Discharge with a large potential difference.
[0003]
Then, Ar ions collide with the target 2, and the reaction causes the atoms of the substance constituting the target 2 to be knocked out and deposited on the surface of the substrate electrode 100. Therefore, if the substrate 4 to be processed is attached on the substrate electrode 100, the surface thereof is covered with a film of a substance constituting the target 2.
[0004]
Since the conventional substrate electrode 100 used here is a metal disk and serves as one electrode in the discharge with the target 2, it is electrically connected to the outside of the vacuum chamber 7 through the central rotating shaft 5. A predetermined potential is set, and as shown in FIG. 6, a plurality of substrates (four are shown) to be coated with a film are provided on the surface (lower surface) facing the target. And is fixed by a mounting screw 102 while being held by a pressing metal fitting 101 so as to surround the rotation center.
[0005]
Further, since the temperature of the surface of the substrate 4 to be processed during film formation greatly affects the physical properties of the formed film, it is necessary to control the temperature of the substrate electrode 100 with high accuracy. Therefore, a heater that is the heating means 6 is installed on the ceiling surface of the vacuum chamber 7, and the substrate electrode 100 is heated by the radiant heat generated by the heater 6. While the temperature of the substrate electrode 100 is measured with a thermocouple (not shown), the heater 6 is ON / OFF controlled to maintain the substrate electrode 100 at a constant temperature in a high temperature region.
[0006]
Further, when the substrate electrode 100 is not heated, a cooling passage (not shown) is provided in the substrate electrode 100 so that the cooling water is circulated to a constant temperature through the rotating shaft 5 so as to maintain the constant temperature.
[0007]
With such a configuration, the substrate electrode 100 is rotated while being discharged between the substrate electrode 100 and the target 2, and the substrate 4 to be processed is successively passed over the target 2. A film is formed.
[0008]
[Problems to be solved by the invention]
However, according to the substrate electrode having the above structure, as shown in FIG. 7, the substrate 4 to be processed having poor flatness and warping or undulation has a gap 10 between the substrate electrode 100 and contact. The area is reduced. Ar gas in the vacuum chamber is very lean compared to the atmosphere, and heat transfer through the gap 10 is hardly performed as compared with heat conduction at the contact portion.
[0009]
For this reason, the efficiency of heat transfer between the substrate electrode and the substrate to be processed is lowered, the temperature followability of the substrate to be processed is poor, and temperature unevenness is likely to occur. As a result, there is a problem that the temperature of the substrate to be processed cannot be accurately controlled.
[0010]
In view of the above problems, an object of the present invention is to provide a substrate electrode capable of accurately controlling the temperature of the substrate to be processed by always maintaining a constant contact between the substrate to be processed and the substrate electrode having poor flatness. .
[0011]
[Means for Solving the Problems]
The object is to provide a substrate electrode on which a substrate to be processed is mounted, an electrode main body having a through-hole formed at a position where the substrate to be processed is held at a position directly facing the heating means, and a film on the substrate to be processed A plurality of heat transfer pins fitted in the through holes so as to elastically press the opposite surface of the formation surface, and the heat transfer pins have a large heat receiving capacity at one end directly facing the heating means. The problem is solved by a substrate electrode configured to have a heat bath portion and a hemispherical head at the other end in contact with the substrate to be processed.
[0012]
With this configuration, the tips of the individual heat transfer pins of the heat transfer unit composed of a plurality of heat transfer pins move (in and out) following the surface of the substrate to be processed (opposite surface of the film formation surface). , Make contact with bullets .
Therefore, poor flatness of the substrate to be processed, even if there are irregularities such as camber or waviness and follows it to absorb irregularities, Ru can be uniformly efficiency good thermal conductivity over the entire surface of the substrate. As a result, the heat conduction efficiency between the substrate electrode and the surface processed substrate is not reduced, the temperature followability of the substrate to be processed is improved, and temperature unevenness is less likely to occur.
[0013]
In addition, the tip of the opposite side of the heat transfer pin directly faces the separately provided heating means, receives the radiant heat from the heating means, and conducts heat to the work substrate. Changes can be buffered.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the gist of the present invention will be described in detail based on the embodiments shown in the drawings.
FIG. 2 shows a substrate electrode provided in the sputtering apparatus. As shown in the figure, the substrate electrode 1 includes a disk-shaped electrode body 13 having a rotating shaft 5 vertically disposed at the center, and a plurality of substrates 4 to be processed (one of four substrates). Between each of the through holes 13a and the heat conduction units 14 fitted in the respective through holes 13a. And a fixing member 12 that supports the workpiece 4 with the substrate 4 interposed therebetween.
[0015]
The heat conduction unit 14 and the fixing member 12 are both attached to the electrode main body 13 by the attachment screws 9, and the substrate 4 to be processed is brought into contact with each heat conduction unit 14 one by one.
[0016]
The heat conduction unit 14 conducts the radiant heat from the heater as the heating means 6 to the substrate 4 to be processed efficiently and uniformly. Therefore, the heat conduction unit 14 includes a disk-shaped heat transfer pin holding member 16 fitted in the through hole 13 a of the electrode body 13 and a film formation of the substrate 4 to be processed inserted into the through hole 13 a of the electrode body 13. A plurality of heat transfer pins 11 erected vertically in a honeycomb shape (see FIG. 4) on the heat transfer pin holding member 16 so as to move independently of each other and come into spring contact with the opposite surface of the surface, and the heat transfer Each of the pins 11 is composed of a coil spring 18 inserted so as to be biased toward the substrate 4 to be processed.
[0017]
The heat transfer pin holding member 16 is formed with pin holes 17 having a small diameter perpendicular to the plate surface in a honeycomb shape, and the heat transfer pins 11 move up and down independently of each other through the pin holes 17.
[0018]
The heat transfer pin 11 is provided with a head 19 on the side in contact with the substrate 4 to be processed, and the head 19 has a hemispherical smoothness in order to ensure that it is in contact with the surface of the substrate 4 at an angle. Make a curved surface. A heat bath 20 is provided on the opposite side of the head 19 in order to increase the heat receiving capacity. Thereby, the rapid temperature change of the head 19 is alleviated.
[0019]
The coil spring 18, which is compressed and inserted between the heat transfer pin holding member 16 and the head portion 19, biases the heat transfer pin 11 toward the substrate 4 to be pressed and presses the head portion 19. In the free state of the heat transfer pin 11, the heat transfer pin 11 is pushed down until the step of the heat bath portion 20 engages with the pin hole 17 of the heat transfer pin holding member 16.
[0020]
The pin holes 17 of the heat transfer pin holding member 16 are opened in a honeycomb shape so that the heat transfer pins 11 are arranged as densely as possible. However, all the heat bath portions 20 are formed as one bundle to form a plane. Can be opened at a close pitch.
[0021]
The fixing member 12 has a circular or square opening 12a having the same shape as the film forming region of the substrate 4 to be processed. The fixing member 12 is supported by the mounting screws 9 so as to support the substrate 4 from the lower side (target side). It is attached to the lower surface of the electrode body 13.
[0022]
FIG. 3 shows a state in which the substrate to be processed is held on the substrate electrode. When the processed substrate 4 having unevenness such as warpage and undulation is pressed against the surface on which the heads 19 of the heat transfer pins 11 are lined by the fixing member 12, the individual heat transfer pins 11 are uneven on the processed substrate 4 at that position. The heat transfer pins 11 move up and down in accordance with the degree of heat, and all the heat transfer pins 11 come into contact with the surface of the substrate 4 to be processed (opposite surface of the film formation surface). It is transmitted to the heat bath 20 and is conducted from each head 19.
[0023]
In order to increase the accuracy and efficiency of temperature control by turning the heater on and off, it is particularly desirable that the heat transfer pin be manufactured using a highly thermally conductive metal such as copper.
In addition, each of the electrode body, heat transfer pin holding member, heat transfer pin, coil spring, and fixing member is made of a conductive metal so as not to disturb the electric field between the substrate electrode and the target. In order to make all of them have the same potential, it is necessary to ensure mutual electrical continuity.
[0024]
The present invention is applied to a direct current sputtering apparatus, and a work substrate made of four alumina plates having a size of 90 mm × 90 mm and a thickness of 700 μm and having irregularities such as warpage and undulation of about 150 μm at maximum is attached to a substrate electrode and heated. The experiment was held at 200 ° C.
[0025]
When a conventional substrate electrode is used, it takes about 68 minutes for the surface of the alumina plate to reach 200 ° C, and after starting temperature control by turning the heater 6 ON / OFF, the temperature is centered on 200 ° C. It moved up and down in the range of ± 8 ° C, and the temperature distribution of the surface of each substrate to be processed was 5 ° C at the maximum.
[0026]
On the other hand, when the substrate electrode of the present invention was used, the temperature of the alumina plate rose to 200 ° C. in about 35 minutes. During temperature control, the upper and lower temperatures were as small as ± 3 ° C., and the temperature distribution on the surface was 1 ° C. or less, confirming that the temperature control was easier and the temperature unevenness was superior to the conventional substrate electrode.
[0027]
In this way, a heat conduction unit including a plurality of heat transfer pins that can be brought into spring contact with the position of the substrate electrode that holds the substrate to be processed is interposed between the substrate to be processed and each heat transfer pin is connected to the substrate to be processed. Because the tip of the heat transfer pin moves (enters and exits) following irregularities such as warping and undulation, and is always in contact with no gaps. The tip on the opposite side directly faces the heating means provided at a distance and receives the radiant heat from the heating means to conduct heat to the work substrate, so that it follows even if the work substrate has poor flatness. Thus, the uneven shape is absorbed, and uniform and efficient heat conduction is possible over the entire surface of the substrate, and the temperature of the substrate to be processed can be controlled more accurately.
[0028]
In the present invention, a cooling passage is provided in the substrate electrode in the same manner as in the prior art, and the cooling water is circulated through the rotating shaft, and the temperature is controlled by circulating when cooling is necessary.
[0029]
【The invention's effect】
As described above in detail, according to the present invention, even a thin plate-like workpiece having unevenness such as warpage and undulation can be uniformly and efficiently conducted from the substrate electrode. For example, the present invention can be applied to a sputtering apparatus to achieve an industrially extremely useful effect that can realize more accurate control of the temperature of a substrate to be processed.
[Brief description of the drawings]
FIG. 1 is a principle view of a substrate electrode according to the present invention. FIG. 2 is a side view of an essential part including a fracture of an embodiment of the substrate electrode according to the present invention. FIG. 4 is a side sectional view of the heat conduction unit of FIG. 3. FIG. 5 is a schematic side view of a sputtering apparatus according to the prior art. FIG. 6 is a perspective view of a substrate electrode according to the prior art. Side view of the main part showing the state where the work substrate is mounted 【Explanation of symbols】
1: Electrode substrate 2: Target 4: Substrate 11: Heat transfer pin 12: Fixing member 12a: Opening 13: Electrode body 13a: Through hole 14: Thermal conduction unit

Claims (1)

In the substrate electrode on which the substrate to be processed is placed ,
In the position directly facing the heating means,
An electrode body having a through hole formed at a position for holding the substrate to be processed;
A plurality of heat transfer pins fitted in the through holes so as to elastically press the surface opposite to the film forming surface of the substrate to be processed ;
The heat transfer pin has a heat bath portion having a large heat receiving capacity at one end directly facing the heating means, and a hemispherical head portion at the other end in contact with the substrate to be processed. Substrate electrode.

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