JP2000129441A - Substrate holding method in sputtering device and substrate holder of device forming thin film on substrate surface in plasma atmosphere - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of concentration of electric loads on a substrate holder, into the space between the edge side of a substrate set in a guide and the guide, by inserting a wedge-shaped substrate holder in such a manner that the upper face is made the same as the surface of the substrate and holding the substrate to a substrate electrode. SOLUTION: A rectangular frame-shaped substrate guide 7 is fixed to the surface of the circumferential edge part of a substrate receiving block 15 in a substrate holder 4. The substrate guide 7 is composed so as to be made slightly larget than the a substrate 3, and, when the substrate 3 is held to the inside of the frame, a slight gap is formed between the guide board 7 and the side edge of the substrate 3. A substrate holder 20 composed into a wedge shape is inserted into the gap, and the substrate 3 is fitted and fixed to a holder plate 6. The holder 20 is composed of steel, aluminum or the like, the plane is made approximately rectangular, and the, tip side is formed into a pointed shape. The holder 20 is piled till the upper face of the holder 20 is made approximately the same as the surface of the substrate 3, by which the substrate 3 can be fixed to the guide 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for holding a substrate in a sputtering apparatus and a substrate holder for an apparatus for forming a thin film on a substrate surface in a plasma atmosphere such as a sputtering apparatus.

[0002]

2. Description of the Related Art For example, in the manufacture of a thin film magnetic head device, an Al ₂ O ₃ film (alumina thin film) as an oxide insulating film is used.
For the deposition of the like or SiO ₂ film, a bias sputtering method is used by the high frequency sputtering apparatus (RF sputtering device). In such an RF sputtering apparatus, in a vacuum chamber, a substrate electrode on which a substrate is placed, and a target that is a material of a thin film formed on the substrate surface are arranged to face each other, and a high-frequency voltage is applied to both the substrate electrode and the target, The plasma is generated between the two electrodes by discharge, and a thin film is formed on the substrate surface in the plasma atmosphere.

When forming a thin film in such a plasma atmosphere, it is necessary to cool the substrate during processing. Conventionally, a water cooling mechanism is provided on a substrate electrode, and the substrate electrode is provided with indium gallium (In-gallium) as a bonding material.
The substrate is cooled by contacting the substrate via Ga).

[0004] Indium gallium used when performing such water-cooled substrate cooling has a problem of industrial pollution and is difficult to collect because of its circumstances.
Instead of the water-cooling method, a gas cooling method of cooling the substrate by flowing a cooling gas on the back surface side of the substrate is becoming popular (for example, see Japanese Patent Application Laid-Open No. 9-228039).

[0005]

However, when the above-mentioned gas cooling method is adopted, even if other sputtering conditions are set in the same manner as in the case of the conventional water cooling, contamination in the thin film formed on the surface of the substrate is caused. It has been reported in various places that the probability of occurrence of nations increases.

As shown in FIG. 10, the inventors of the present application also attach and hold a substrate 52 to a substrate electrode 51 (substrate holder) having a gas cooling mechanism, perform sputtering by a side sputtering apparatus, and When the formed thin film was inspected, a relatively large amount of dust was mixed in the thin film formed on the substrate surface as compared with the case where side sputtering was performed under the same conditions while cooling the substrate by a water cooling method. .

The substrate electrode 51 having the gas cooling mechanism has a cooling gas flow passage 53 for flowing a cooling gas to the back surface of the substrate 52 on the substrate mounting surface (upper surface), and the cooling gas passage 53 is formed on the substrate mounting surface (upper surface). An annular sealing material 54 surrounding the passage 53 is fitted into an annular groove 55 provided on the upper surface of the substrate electrode 51, and the sealing material 54 is pressed against the back surface of the substrate 52 to prevent leakage of the cooling gas.

Therefore, the substrate 52 exposed to plasma in the vacuum chamber of the sputtering apparatus is directly cooled by the cooling gas flowing through the flow passage 53, and heat is released to the substrate electrode 51 via the gas.

A guide 57 for guiding and holding the substrate 52 is attached to the substrate electrode 51. The substrate 52 fitted in the guide 57 is screwed to the guide 57 by screws 58.
By holding down from above by means of a washer 59 attached to the guide 57, it is held so as not to come off the guide 57.

[0010]

Means for Solving the Problems The present inventors have intensively studied and clarified the cause of contamination when a gas cooling method is used as a substrate cooling mechanism. That is, in the case of gas cooling, since the substrate 52 is directly cooled by the cooling gas, the substrate electrode 51 does not need to be cooled much as compared with the case of the water cooling type. The gas-cooled type 57 has a relatively higher temperature than the water-cooled type. Then, the board guide 5
The washer 59 attached to 7 is exposed to the plasma and becomes considerably high in temperature. That is, according to the gas cooling system,
The substrate 52 is cooled to an appropriate temperature, but its surroundings are exposed to plasma and heated, so that the substrate electrode 51 has a relatively high temperature.

According to measurements made by the inventors of the present invention in the above apparatus, the temperature of the substrate 52 is about 60 ° C., but the temperature of the substrate electrode (holder) has risen to about 140 to 150 ° C. When the substrate electrode is heated to a high temperature, the washer 59 mounted on the guide and exposed to the plasma becomes considerably hot, and the thin film formed on the surface of the washer 59 undergoes film peeling due to the high heat. The fragments fly off for some reason and mix with the substrate surface.

Particularly, in the case of bias sputtering, the substrate 52
The inventors of the present application have found that since the washer 59 for holding the liquid crystal is protruded from the surface of the substrate 52, charge concentration occurs in the washer 59, and the film formed on the washer flies off due to excessive charge. I found it.

The present invention has been made based on such findings.
In a vacuum chamber, a substrate electrode on which a substrate is placed and a target, which is a material of a thin film formed on the substrate surface, are arranged to face each other, a high-frequency voltage is applied to both the substrate electrode and the target, and discharge is caused between both electrodes. In a bias sputtering type sputtering apparatus that forms a thin film on a substrate surface by generating plasma, a wedge-shaped substrate holder is placed in a gap between a guide and a side edge of a substrate provided in a guide provided on a substrate electrode. The substrate holding method in the sputtering apparatus, wherein the substrate is held on the substrate electrode by fitting the substrate so as to be substantially flush with the surface of the substrate.

According to this holding method, since the holder for pressing and holding the substrate against the substrate electrode does not protrude greatly from the substrate surface, it is possible to prevent the concentration of electric charges on the holder while employing the bias sputtering method. Is done. Therefore, the thin film formed on the upper surface of the substrate holder is hardly repelled due to the charge overload, and contamination of dust into the thin film formed on the substrate surface is reduced. Furthermore, since the holder of the present invention has a relatively small area of the upper surface exposed to the plasma and the side surface is strongly pressed against the substrate or the guide, the holder can be provided without cooling means for the holder. Is prevented from being overheated, and the occurrence of film peeling due to high heat is reduced. In addition, since the work of holding the substrate on the substrate electrode is also performed by driving a wedge-shaped holder into the gap between the substrate and the guide, the operation is simplified and speeded up, and the substrate is easily and quickly removed. Can be done.

Further, in the above method, a cooling gas flow passage for flowing a cooling gas to the back surface side of the substrate is formed on the substrate installation surface of the substrate electrode, and an annular sealing material surrounding the flow passage is provided on the back surface of the substrate. When a gas-cooled substrate cooling mechanism is installed so as to be in contact with the substrate electrode, the holder is cooled by the substrate electrode by mounting the substrate holder so as to be in contact with the substrate electrode. Reduced.

Further, since the substrate is held by the wedge-shaped holder so as to be pressed obliquely, the holding state of the substrate is stabilized, and the sealing material is securely pressed against the back surface of the substrate, thereby providing airtightness. In addition to improving the performance, there is also an effect that the substrate can be reliably pressed against the substrate electrode and a bias can be reliably applied to the substrate.

Further, it is preferable to use a substrate holder having a large number of fine irregularities on the entire upper surface thereof. Such a substrate holder can be formed, for example, by forming the upper surface of the substrate holder as a flat surface and performing blast processing on the upper surface. By roughening the upper surface on which the thin film is formed by being exposed to the plasma, the adhesion of the film is improved, and the occurrence of film peeling is further prevented.

The present invention can be applied not only to the bias sputtering apparatus but also to a substrate holder of an apparatus for forming a thin film on a substrate surface in another plasma atmosphere. That is, the present invention includes a holder plate on which the substrate is detachably mounted, and a guide for guiding the installation position of the substrate, and a cooling gas flow passage is formed on the substrate installation surface of the holder plate, In a substrate holder in which an annular sealing material surrounding the flow passage is mounted so as to abut against the back surface of the substrate, a substrate installed on the substrate mounting surface so as to press the substrate against the sealing material and to sandwich the substrate from the side. A plurality of wedge-shaped holders fitted in the gap between the guide and the guide, and the holder is dimensioned such that the upper surface thereof is substantially flush with the substrate surface in the fitted state. 1 is a substrate holder of an apparatus for forming a thin film on a substrate surface in a plasma atmosphere.

It is preferable that the tip of the holder is also in contact with the holder plate in such a substrate holder. When the thin film forming apparatus is a bias sputtering apparatus, the holder plate serves as a substrate electrode.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 9 is a schematic diagram of an RF sputtering apparatus 1 according to one embodiment of the present invention. The apparatus 1 includes a vacuum chamber 2 and a substrate 3 is installed and held in the chamber 2. Substrate holder 4
And a target 5 which is a material of a thin film formed on the surface of the substrate 3 is arranged to be opposed to each other.

The substrate holder 4 has a holder plate 6 serving as a substrate electrode and a substrate guide 7 provided on the holder plate 6. The board guide 7 is formed in a frame shape along the peripheral shape of the board 3, and the board 3 is guided and held in the guide 7.

The target 5 is bonded to the surface of the target electrode 8 by, for example, a known indium-based bonding material. The substrate electrode 6 and the target electrode 8
They are connected to high frequency power supplies 11 and 12 via matching boxes 9 and 10, respectively. The target electrode 8 has a cooling structure in which cooling water flows.

The RF sputtering apparatus 1 is of a side sputtering type, in which a high-frequency voltage is applied to both the substrate electrode 6 and the target electrode 8, and a plasma is generated between both electrodes by a discharge. To form a thin film on the surface of the substrate 3.

FIG. 7 and FIG. 8 show an embodiment of the substrate holder 4 of the apparatus 1. This substrate holder 4
It is configured to be able to hold nine substrates 3. The holder plate 6 of the holder 4 includes a plate substrate 13 made of a steel plate material, a copper block 14 mounted on the substrate 13, a substrate receiving block 15 disposed between the copper blocks 14, and a copper block 14. A holder cover 16 that covers the surface and a shield ring 17 provided on the outer periphery of the holder cover 16 are provided. This shield ring 17
An earth shield ring 18 for controlling the direction of the electric field during the sputtering process is provided on the outer peripheral side of the.

The holder cover 16 is divided into four parts around the plurality of substrates 3, and is attached without any gap except for the substrate installation surface of the plate 6.

FIGS. 1 to 6 show in detail an embodiment of the substrate receiving block 15 of the substrate holder 4 and a structure for attaching the substrate holder 4 to the block 15. In this embodiment, a rectangular frame-shaped substrate guide 7 is attached and fixed on the peripheral edge of the substrate receiving block 15 as a whole. The guide 7 may be divided by a plurality of metal fittings. The upper surface of the substrate guide 7 is substantially flush with the upper surface of the holder cover 16 and is also substantially flush with the upper surface (front surface) of the substrate 3 fitted in the guide 7. .

The board guide 7 is slightly larger than the board 3 so that when the board 3 is held in the frame, a slight gap is formed between the guide 7 and the side edge of the board 3. I have to. Then, the substrate 3 is attached and fixed to the holder plate 6 by fitting a wedge-shaped substrate holder 20 as shown in FIG.

The holder 20 is made of steel, aluminum, or the like, has a substantially rectangular shape in plan view, and is formed with a tapered tip end (inset side). The thickness of the upper end is slightly larger than the gap between the substrate 3 and the guide 7. Therefore, the substrate 3 can be fixed to the guide 7 by driving the holder 20 until the upper surface of the holder 20 is substantially flush with the surface of the substrate 3. Preferably, the thickness of the tip is about 1 mm, the thickness of the upper end is about 2 mm to 3 mm, the height is about 3 to 5 mm, and the length is about 10 mm.

The upper surface of the holder 20 is subjected to shot blasting with alumina beads to form a large number of fine irregularities so that the entire surface has a satin finish.

Further, in the illustrated example, in order to hold the rectangular substrate 3, two holders 20 are driven into each side of the substrate 3 at an interval, so that one substrate 3 can be held in total. Eight holders 20 are used. Of course, more holders 20 may be used. Further, it is preferable to drive at least one holder 20 for each side. Note that the holder 20 of the present invention can also be used to hold a circular substrate. In this case, it is preferable to use the holder 20 curved along the peripheral shape of the substrate.

The upper surface of the substrate receiving block 15 is a substrate installation surface, and the substrate 3 is installed on the installation surface. Since a bias voltage from the power supply 11 is applied to the block 15, by bringing the substrate 3 into contact with the block 15, a bias can also be applied to the substrate 3.

On the upper surface of the block 15, a cooling gas flow passage 21 for flowing a cooling gas is formed. In the illustrated example, the flow passage 21 has a circular groove shape in plan view, but is not limited to such a shape, and may have various shapes. A gas supply pipe 2 for supplying a cooling gas such as argon or helium is provided in the flow passage 21.
2 and a gas discharge pipe 23 for discharging the heated gas
And are connected. It is preferable to use the same cooling gas as the gas supplied into the vacuum chamber 2 for plasma generation so that a large adverse effect does not occur even if a gas leak occurs.

On the upper surface of the block 15, there is formed an annular groove 24 which surrounds the outer peripheral side of the flow passage 21, and a sealing member 25 made of an O-ring is attached and held in the annular groove 24. The sealing material 25 is slightly swelled upward from the groove 24, and is elastically deformed by placing the substrate 3 on the block 15 and pressing and holding the substrate 3 downward by the holder 20, thereby maintaining airtightness. Like that.

When the holder 20 is brought into contact with the substrate receiving block 15 of the holder plate 6 through which the cooling gas flows, the heat of the holder 20 can be released to the block 15. Heating can be prevented.

The holder plate 6 is provided with a water passage 26, and the cooling water flowing through the water passage 26 cools the holder plate 6 to some extent. In this embodiment, the water channel 26 is formed over the copper block 14 and the substrate receiving block 15. In addition, waterway 26
There is provided a water supply pipe 27 for supplying cooling water and a water distribution pipe 28 for discharging heated cooling water.

In the method for holding a substrate by the substrate holder 4 according to the above-described embodiment, the rectangular substrate 3 is inserted into the gap between the four sides of the substrate 3 and the guide 7 near each side by the wedge-shaped holder 20. Since the substrate 3 is held by sandwiching the substrate 3 from the front, rear, left, and right sides, the substrate 3 is not shaken, and the wedge-shaped holder 20 is driven into the gap so that the substrate 3 Since it is pressed against the substrate installation surface of the receiving block 15, the sealing by the sealing material 25 can be ensured. Further, by such a holding method, it is possible to eliminate a portion protruding from the substrate surface around the substrate,
Even if bias sputtering is performed, charge concentration can be prevented from occurring, and the ratio of the surface of the holder 20 exposed to plasma can be reduced, so that film separation due to heating of the holder 20 can be reduced. Furthermore, by forming the surface of the holder 20 in a satin shape, the adhesive force of the film is improved,
Film peeling is reduced.

The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, the board guide 7
Can be formed in a circular frame shape, and is not limited to the frame shape, and may be formed by a projecting guide projecting from the holder plate.

[0038]

According to the present invention, the holding of the substrate, which is particularly necessary when performing side sputtering or up sputtering, can be performed by the wedge-shaped holder which does not protrude from the substrate surface. Even in the case of carrying out the method, it is possible to prevent charge concentration from occurring on the substrate holder, and since the holder is inserted into the gap between the substrate and the substrate guide, the temperature rise is increased even in a plasma atmosphere. Thus, the film formed on the surface of the holder can be prevented from being peeled off due to overheating, whereby contamination on the substrate surface can be reduced.

Further, by roughening the upper surface of the holder, the adhesive force of the thin film formed on the upper surface of the holder exposed to plasma can be improved, and the occurrence of film peeling can be further reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view of a main part showing a substrate holding structure according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a substrate holder according to the embodiment.

FIG. 3 is an enlarged plan view of a main part of the substrate holding structure according to the embodiment.

FIG. 4 is a plan view of a substrate receiving block constituting a holder plate of the substrate electrode according to the same embodiment.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a sectional view taken along line BB of FIG. 4;

FIG. 7 is an overall plan view of a substrate electrode (substrate holder) according to the same embodiment.

FIG. 8 is an overall vertical sectional view of the substrate electrode.

FIG. 9 is a simplified configuration diagram of an RF sputtering apparatus.

FIG. 10 is a longitudinal sectional view showing an example of a washer-type substrate holding structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sputtering apparatus (device which forms a thin film on a substrate surface in a plasma atmosphere) 2 Vacuum chamber 3 Substrate 4 Substrate holder 5 Target 6 Substrate electrode (holder plate) 7 Guide 21 Cooling gas flow path 25 Sealing material

Continued on the front page (72) Inventor Hiroshi Oshita 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka F-term in ReadWrite SMI Co., Ltd. 4K029 CA05 DC32 DC35 JA01 JA06

Claims (5)

[Claims] In a vacuum chamber, a substrate electrode on which a substrate is placed and a target which is a material of a thin film formed on the surface of the substrate are opposed to each other, and a high-frequency voltage is applied to both the substrate electrode and the target. In a bias sputtering type sputtering apparatus that generates plasma by discharge between electrodes to form a thin film on the substrate surface, a wedge-shaped substrate is held in the gap between the guide and the side edge of the substrate installed in the guide provided on the substrate electrode A method for holding a substrate in a sputtering apparatus, wherein a substrate is held on a substrate electrode by fitting a tool so that an upper surface thereof is substantially flush with a surface of the substrate. 2. A cooling gas flow passage for flowing a cooling gas to the back surface side of the substrate is formed on the substrate installation surface of the substrate electrode, and an annular sealing material surrounding the flow passage is brought into contact with the back surface of the substrate. 2. The method for holding a substrate in a sputtering apparatus according to claim 1, wherein the substrate holding tool is mounted so as to be in contact with a substrate electrode. 3. The method for holding a substrate in a sputtering apparatus according to claim 1, wherein the substrate holder has a large number of minute irregularities on the entire upper surface thereof. 4. A substrate holder for an apparatus for forming a thin film on a substrate surface in a plasma atmosphere, comprising: a holder plate on which a substrate is detachably mounted; and a guide for guiding an installation position of the substrate. In the substrate mounting surface, a cooling gas flow passage is formed, and in a substrate holder in which an annular seal material surrounding the flow passage is mounted so as to abut on the back surface of the substrate, the substrate is pressed against the seal material. A plurality of wedge-shaped holders fitted in a gap between the substrate and the guide provided on the substrate installation surface so as to sandwich the substrate from the side, and the holder has an upper surface in the fitted state. A substrate holder for an apparatus for forming a thin film on a substrate surface in a plasma atmosphere, which is dimensioned so as to be substantially flush with the substrate surface. 5. A substrate for forming a thin film on a substrate surface in a plasma atmosphere according to claim 4, wherein a large number of fine irregularities are formed on the entire surface of the wedge-shaped holder. holder.