JPS62235469A - Method for cooling substrate in sputtering device - Google Patents

Abstract

PURPOSE:To sputter a film on a substrate such as a thermoplastic resin substrate having a low heat-resistant temp. without reducing the film forming rate by circulating a sputtering gas around the outer wall of a liquefied nitrogen tank provided in the sputtering chamber of a sputtering device to cool the gas, and then passing the gas over the rear surface of a film forming substrate. CONSTITUTION:The substrate 8 fixed to a substrate holder 7 is transferred to a vacuum treating chamber 1 by conveying systems 13, 14, and 15, and then the inside of the vacuum treating chamber 1 is evacuated to high vacuum. A sputtering gas is introduced between the outer wall 9 of the liquefied nitrogen tank 2 provided on the rear surface side of the substrate and a cooling plate 5 from a sputtering gas source 12 through an inlet 6, circulated around the outer wall of the liquefied nitrogen tank by a slit 18, and cooled. A fixed amt. of the gas is blown off from a blowoff port 17 to sufficiently cool the substrate 8, hence the temp. increase from the surface is prevented, and a film can be sputtered at a fixed film forming rate even on a low-m.p. substrate of a thermoplastic resin, etc.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a thin film forming apparatus, particularly an apparatus for forming a film on a substrate such as sputtering, in which internal stress during film formation causes a rise in temperature of the substrate. In addition, the present invention relates to a method for cooling a substrate in a sputtering apparatus when the substrate is made of a thermoplastic resin such as PC (polycarbonate) or PMMA (gelimethyl methacrylate) and has a low allowable temperature limit (approximately 80° C. or less).

[Conventional technology]

Conventionally, particularly in sputtering apparatuses for semiconductors, a substrate heating section for increasing the film formation rate and a cooling section after film formation are usually configured on the back side of the substrate (on the opposite side to the sputtering surface). In this case, the purpose of cooling is to quickly lower the temperature of the substrate and its supporting components, which have been heated to several hundred degrees O. In addition, the cooling method involves connecting the part that supports the heater to a water cooling tank or water cooling pipe, and circulating water from the outside.

is normal.

[Problem that the invention seeks to solve]

However, when forming a film by sputtering on a substrate with a low allowable temperature limit such as a thermoplastic resin substrate, heating as described above cannot be achieved using the conventional technology, and furthermore, the substrate surface on the target side is affected by kinetic energy due to collisions of sputtered atoms and molecules. It has been shown that this causes internal stress, which leads to an increase in temperature. Experiments have shown that temperature increases are caused by target electrode output, gas pressure, and distance between substrates in the same device, but it is possible to lower the output or increase the distance between substrates in order to lower the substrate surface temperature. Leads to membrane speed reduction. Therefore, it is necessary to cool the substrate in order to prevent the temperature from rising while maintaining a certain film formation rate. However, in the conventional cooling method, the thermal conductivity of the substrate is low, and since it is in a vacuum, heat sub-irradiation such as a water cooling tank has little effect. An object of the present invention is to provide a device whose purpose is to cool the substrate to a temperature below its allowable temperature limit.

[Means for solving problems]

In the sputtering apparatus of the present invention, Ar gas and other sputter gases necessary for sputtering are cooled by circulating around the outer wall of a liquid nitrogen tank provided in a sputtering chamber, and then flowed onto the back surface of the film-forming substrate during sputtering. It is characterized by preventing a temperature rise caused by film formation on the substrate.

[Effect]

In the sputtering apparatus configured as described above, the sputtering gas is sufficiently cooled while being circulated in contact with the outer wall surface of the liquid nitrogen tank. By flowing this cooled sputtering gas over the entire surface of the substrate from a position as close as possible to the back surface of the substrate, it is possible to cool the substrate and the substrate holder and prevent the temperature rise on the surface from reaching the allowable temperature.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is an overall configuration diagram of an embodiment of the present invention. After the substrate 8 attached to the substrate holder 7 in the preparation chamber (not shown) is transferred to the vacuum processing chamber 1 by the transfer system (13, 14, 15), the gate pulp with the preparation chamber is closed and the specified It is evacuated to a vacuum level. Next, when the pulp 11 is opened from the sputtering gas source 12 between the outer wall 9 of the liquid nitrogen tank 2 provided on the back side of the substrate and the cooling plate 50, the inlet 6
More sputtering gas is introduced and is circulated through the outer wall of the liquid nitrogen tank through the slit 18.

The circulated and cooled sputtering gas is blown out from the sputtering gas outlet 17 onto the back surface of the substrate, and the substrate is sufficiently cooled to prevent the temperature from rising from the front surface.

Furthermore, when the liquid nitrogen evaporates into the air and becomes low, the liquid nitrogen can be supplied from the liquid nitrogen inlet 4 provided externally.

〔Effect of the invention〕

As described above, according to the present invention, sputtering gas is cooled by circulating around the outer wall of a liquid nitrogen tank provided in a sputtering chamber, and then is flowed onto the back surface of a substrate during sputtering to form a film on the substrate. Temperature increases caused by the membrane can be easily prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the substrate cooling method of the sputtering apparatus of the present invention, FIG. 2 is a perspective view of the substrate cooling section in the sputtering apparatus of the present invention, and FIG. 3 is a cross-sectional view of the substrate cooling section. figure. 1...Vacuum processing chamber 2...Liquid nitrogen tank 3...Liquid nitrogen 4...Liquid nitrogen Inlet port 5...Sputter gas cooling plate 6...
...Sputter gas introduction lower ...... Substrate holder 8 ...... Substrate 9 ...... Liquid nitrogen tank outer wall 10 ...
...Target electrode section 11...Gate valve 12...Gas source 13...Transport guide 14...Transport rack 15...Transport gear 16...Rotation introduction terminal 17...Sputter gas outlet 18...Slit

Claims (1)

[Claims] A sputtering gas is cooled by circulating it around the outer wall of a liquid nitrogen tank provided in a sputtering chamber, and then is flowed onto the back surface of a substrate on which a film is being sputtered, thereby preventing a temperature rise caused by film formation on the substrate. Substrate cooling method for sputtering equipment.