JPH0576542B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pallet moving type sputtering apparatus that forms a thin film using a sputtering phenomenon.

(Prior art) In recent years, thin film forming technology using sputtering phenomenon has been used in the semiconductor industry, for example, for semiconductor protective films, IC circuit parts, etc., as well as for compact disks, optical disks, and optical disks, which have rapidly expanded in industrial scale in recent years. It is widely used in a wide variety of applications, including the media manufacturing field of optical memory devices such as magnetic disks.

In general, thin film formation by sputtering can form thin films over a larger area and with more uniform properties than thin film formation by vacuum evaporation, which has been the mainstream until now.It also has a high melting point, which makes it impossible to form thin films with resistance heating vapor deposition. It has advantages such as being able to easily form a thin film even if it is made of other materials.

(Problems to be Solved by the Invention) However, although thin film formation by sputtering has the above-mentioned advantages, the thin film formation speed is considerably slower than that of the vapor deposition method, and the substrate is exposed to plasma. These factors together have the drawback of increasing the substrate temperature, which places restrictions on the substrates on which thin films are to be formed. In recent years, to take the example of optical memory devices, substrates have been shifting from conventional glass to inexpensive plastics, and there has been an increasing need to form films on plastic substrates by sputtering.
As is well known, so-called engineering substrates are used as substrates for optical memory devices such as optical disks.
Plastics used include acrylic (PMMA), polycarbonate, and epoxy resin, all of which have heat distortion temperatures of about 150°C. Therefore, when forming a thin film on the plastic substrate by sputtering, it is necessary to suppress the temperature rise to below this thermal distortion temperature.

Generally, in sputtering equipment, in order to reduce the rise in substrate temperature, the substrate is closely held in a holder inside the equipment that is cooled by water or air cooling, but this was developed to improve productivity. In a pallet moving type sputtering apparatus, that is, one in which the substrate is placed on a pallet and the pallet is moved over the discharge target by a chain drive etc. to form a film, the inside of the apparatus is moved horizontally, vertically, etc. at any time. Mechanically, it is extremely difficult to effectively cool substrates on a plurality of moving pallets.

Furthermore, in the above-mentioned pallet moving type sputtering apparatus in which a plurality of pallets are continuously formed into films, there is a concern that the temperature of the atmosphere in the vacuum chamber increases over time, causing an increase in the substrate temperature.

Below, the results of studies conducted by the inventors on the internal temperature of the device and the substrate temperature will be described.

FIG. 3 shows a partial schematic sectional view of the pallet moving type sputtering device that was studied.

Reference numeral a indicates the wall of the vacuum chamber of the sputtering device, and the surrounding area is water-cooled. Reference numeral b designates a target mechanism section, and this device is of a planar magnetron cathode type, and consists of a rectangular target (including a bonding plate), a target water cooling mechanism, a target electrode, and the like. A plurality of target mechanism sections b are provided adjacent to each other. Reference numeral c denotes a pallet chucked with substrates d, which is moved horizontally over the target mechanism section b by chain drive. Symbols e and f are generally called adhesion prevention plates, which are provided to prevent contamination of the vacuum chamber of the apparatus by sputtering particles, and need to be replaced from time to time.

Therefore, in this device, the anti-adhesion plates e and f are made of SUS plates with a thickness of about 1 mm, in consideration of ease of replacement and for the purpose of satisfying the anti-adhesion effect.
It has a structure in which it is attached to a spacer bolt g provided in the.

As a result of various studies on the above equipment, we found that during film formation by sputtering, the adhesion prevention plate may be damaged due to radiant heat from the target surface or collision of sputtering particles, condensation heat of flying particles during film formation, electron collision, etc. Heat is generated near the surfaces e and f, but the adhesion prevention plates e and f are only interposed between the water-cooled vacuum chamber wall a and the spacer bolt g, and the generated heat is transferred by thermal conduction. The amount escaping to the vacuum chamber wall a is extremely small. Therefore, the temperature of the adhesion prevention plates e and f rises rapidly with discharge time,
It has been found that the radiant heat from the surfaces of the adhesion prevention plates e and f significantly increases the temperature of the substrates d... on the pallet c that are passing through and moving nearby.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a novel pallet moving type sputtering apparatus that reduces the rise in substrate temperature during sputtering.

(Means for Solving the Problems) The pallet moving sputtering apparatus of the present invention is a pallet moving sputtering apparatus in which a substrate is placed on a pallet and moved over a discharge target to form a thin film on the substrate. , the vacuum chamber in which the discharge target is provided is provided with an anti-adhesive member that protects the vacuum chamber in which the discharge target is provided from contamination by sputtering particles and has a cooling effect; It is mounted in surface contact with the wall of the vacuum chamber, which is cooled for the purpose of cooling.

(Function) By forming the adhesion-preventing member into a block shape with a large heat capacity and attaching it in surface contact with the wall of the vacuum chamber, which is being cooled, the temperature rise of the adhesion-preventing member due to sputtering is reduced. Radiant heat from the surface of the adhesion prevention member is suppressed. By this,
There is no risk of raising the temperature of the substrates on the pallet that moves near the adhesion prevention member.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a partial schematic sectional view showing an embodiment of a pallet moving type sputtering apparatus according to the present invention.

The vacuum chamber wall 1 of this sputtering apparatus is cooled around the circumference by water, and one vacuum chamber wall 1 is provided with a plurality of target mechanisms 2 in series. These target mechanism sections 2 consist of a rectangular target, a target water cooling mechanism, a target electrode, and the like. In addition, the substrate 4...
A chucked pallet 3 is provided so as to be movable in the horizontal direction (see the arrow in the figure) above the target mechanism section 2, and this pallet 3 is moved by a chain drive (not shown). Further, a portion of the vacuum chamber wall 1 opposing the target mechanism portion 2...
Adhesion prevention members 7, 8, . . . have a cooling effect and prevent contamination of the vacuum chamber 9 by sputtering particles.
are installed respectively.

Both of these adhesion prevention members 7..., 8... are screwed to the vacuum chamber wall 1 so that they can be replaced at any time when the amount of adhesion of sputtering particles increases.
In addition, the shape of the contact surface has been considered to make surface contact with the vacuum chamber wall 1 as much as possible within the dimensions and shape of the vacuum chamber 9, and in order to improve heat conduction efficiency, it is not plate-shaped but has a large heat capacity. It is shaped like a block. In addition, the material of the adhesion prevention members 7..., 8... is as follows:
Aluminum is preferably used because it has relatively good thermal conductivity and to reduce weight.

Next, the effects of the present invention will be explained in comparison with those of the conventional example with reference to FIG.

In Figure 2, the black circle plot connected by dotted lines is the third
These are the results of substrate temperature measurement using the conventional sputtering apparatus shown in the figure. The substrate temperature was measured by attaching a commercially available thermolabel to the substrate. The horizontal axis is the number of pallets processed for film formation, and the vertical axis is the substrate temperature on the first pallet (T ₁ point in the second).
Indicates the value normalized by . As is clear from this figure, in the conventional sputtering apparatus, as the number of pallets to be processed increases, the substrate temperature increases.

On the other hand, in FIG. 2, the white circle plots connected by solid lines are the results of substrate temperature measurement using the apparatus according to the present invention. As is clear from this figure, the substrate temperature is almost constant regardless of the number of pallets to be processed.

Furthermore, at the same time as the substrate temperature measurement, the surface temperature of each of the above-mentioned adhesion prevention plates and adhesion prevention members was also measured, and the surface temperature of the adhesion prevention member of the apparatus according to the present invention was as follows even when five pallets were subjected to the film forming process. The surface temperature was less than 1/2 of the surface temperature of the adhesion-preventing plate after two pallets were formed using a conventional device.

From the above, according to the present invention, it is possible to significantly reduce the temperature rise of the adhesion-preventing member, thereby reducing the temperature rise of the substrate, and even when a large number of pallets are continuously formed, it is possible to reduce the temperature rise over time. It can be seen that stable film formation is possible without increasing the substrate temperature.

In this embodiment, aluminum is used as the material for the adhesion prevention members 7, 8, but the present invention is not limited thereto. That is, the adhesion prevention member 7
The material may be any material as long as it can effectively release the heat generated on the surfaces of ..., 8, or the heat supplied to the surfaces to the vacuum chamber wall 1 by thermal conduction.
In other words, the material is limited as long as it has a cooling effect due to heat conduction between the cooled vacuum chamber wall 1 and the cooling effect does not have an adverse thermal effect on the substrate during sputtering film formation. It's not a thing.

(Effects of the Invention) As described above, in the device of the present invention, the adhesion-preventing member is formed into a block shape with a large heat capacity and is attached to the wall of the vacuum chamber in surface contact. It is possible to reduce the temperature rise due to sputtering of the member, and it is possible to reduce the temperature rise of the substrate during sputtering film formation. Therefore, stable film formation can be performed even on substrates with low heat resistance such as plastic substrates.

[Brief explanation of the drawing]

FIG. 1 is a partial schematic sectional view showing an embodiment of a pallet type sputtering apparatus according to the present invention, and FIG. 2 shows changes in substrate temperature and number of film forming pallets during sputtering film formation using the conventional apparatus and the apparatus according to the present invention. A characteristic diagram showing the relationship, FIG. 3, is a partial schematic sectional view of a conventional pallet type sputtering apparatus. 1... Vacuum chamber wall, 2... Target mechanism section, 3
...Pallet, 4...Substrate, 7, 8...Adhesion prevention member.

Claims (1)

[Claims] 1. In a pallet moving sputtering device in which a substrate is placed on a pallet and moved over a discharge target to form a thin film on the substrate, the vacuum chamber in which the discharge target is provided is protected from contamination by sputtering particles and is cooled. The device is equipped with an effective anti-adhesive member, which is formed in the form of a block with a large heat capacity, and is attached in surface contact with the wall of the vacuum chamber, which is cooled to improve heat conduction. A pallet moving sputtering device characterized by: