JPH04325679A - Substrate holder - Google Patents

Abstract

PURPOSE:To prevent the failure in mounting of substrates and the dislodgment from the substrate holder of an inline type sputtering device without generating plastic deformation even in a high-temp. atmosphere by constituting the above- mentioned holder of Ti or Ti alloy. CONSTITUTION:The substrate holder 1 used in the inline type sputtering device in which a robot is used for attaching and detaching the substrates is constituted of a sheet consisting of the Ti or Ti alloy having plural substrate holding parts 7. Nearly circular apertures 9 are formed in the substrate holding parts 7 and U-shaped grooves 10 are formed in the peripheral edge parts on the lower side thereof. The circular substrates transported by the robot are held in the grooves 10 in the apertures 9. The substrate holder 1 is made of the Ti or Ti alloy and, therefore, the generation of the plastic deformation by the effect of high temp. does not arise at the time of putting the holder 1 into the high- temp. atmosphere of >=300 deg.C and forming the films by sputtering. The failure in mounting the substrates to the holding parts 7 of the substrate holder 1 and the dislodgment of the substrates from the holder 1 are thus prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate holder, and more particularly to a substrate holder suitable for use in an in-line sputtering apparatus that uses a robot to attach and detach a substrate.

0002

[Prior Art and its Problems] FIG. 1 shows the entire structure of a substrate attachment/detachment device in a conventional in-line sputtering apparatus. Although disclosed in JP-A No. 61-6274, it is shown in a position taken out from a vacuum chamber (not shown), and a support part 14 is integrally formed at the lower end of the support part 14. The substrate holder 1 can be introduced into the vacuum chamber and fixed by a transport mechanism (not shown) installed in the vacuum chamber and placed at a predetermined position, or it can be moved from the vacuum chamber to the position shown in the diagram by the transport mechanism outside to attach or remove the substrate. It is now being taken out. A robot main body 3 is arranged near this substrate holder 1,
This robot is equipped with a hand 2, which can be moved vertically and horizontally in the figure by a drive mechanism provided within the robot body 3.

In FIG. 2, the substrate holder 1 is made of a thin plate, on which nine substrate holding parts 7 are formed (in the above publication, a larger number of substrate holding parts are formed, but for the sake of simplifying the diagram, ). Each of these is provided with a substantially circular opening 9 and a U-shaped groove 10 on its lower periphery as best seen in FIG. Although the groove 10 extends in an arc, a circular substrate carried by the robot body 3 is brought into the opening 9, and the substrate is held in the groove 10 by operating the hand 2 at a predetermined position. After each substrate holding section 7 holds the substrate as described above, the substrate holder 1 is moved to its supporting section 1 in FIG.
4 is held firmly and introduced into a vacuum chamber by a transport mechanism, and a known sputtering operation is performed.

As described above, the substrate holder for an in-line continuous sputtering film forming apparatus is a jig for loading a substrate and transporting it within the sputtering apparatus.

[0005] A substrate holder for an in-line film forming apparatus that forms a film in an atmosphere with a temperature of over 300° C. is required to not undergo plastic deformation due to heating during the film forming process. The reason is■
■ The substrate must be reliably loaded onto the substrate holder, ■ The substrate must not fall off the substrate holder during transportation, and ■ The dimensional alignment between the substrate holder and peripheral parts inside the sputtering equipment may become defective during the transportation process. This is to prevent transport from becoming impossible.

Conventionally, substrate holders have been made of aluminum alloy or stainless steel, but these materials have the following problems.

(1) The problem with aluminum alloys is that some aluminum alloys have mechanical strength comparable to steel at room temperature, but
Mechanical strength rapidly decreases from 200°C or higher, reaching 300°C.
At temperatures above ℃, practical strength cannot be maintained and plastic deformation occurs. 4 and 5 show the mechanical strength-temperature characteristics of typical high-strength aluminum alloys. Aluminum alloys are said to have low mechanical strength at high temperatures, and there are few materials regarding reliable mechanical properties at temperatures above 300°C.

(2) The problem with stainless steel is that although it has high mechanical strength at high temperatures, it has low thermal conductivity, so when it is heated by radiation using an infrared heater like a substrate holder, local temperature unevenness tends to occur. Furthermore, since stainless steel has a large coefficient of thermal expansion, local temperature unevenness appears as a large difference in thermal expansion. As a result, large internal stress occurs, leading to plastic deformation.

[0009] Due to the above-mentioned problems, substrates on which films are formed at temperatures exceeding 300°C, for example, substrates used for forming magnetic films for magnetic recording hard disks or transparent conductive films for liquid crystal displays, etc. When used for transportation, the above-mentioned problems often occur.

0010

Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned problems, and provides a substrate holder that does not cause the above-mentioned problems even when forming a film on a substrate in a heated atmosphere of 300° or more. The purpose is to provide

[0011]

[Means for solving the problem] The above object is achieved by a substrate holder for holding a substrate to be formed into a film in a heated atmosphere, which is characterized by being made of titanium or a titanium alloy. be done.

0012

[Function] Even when titanium or titanium alloy is heated to over 300°C, its yield strength and maximum deformation resistance temperature difference are larger than those of conventional materials, so it does not undergo plastic deformation. Therefore, the substrate can be reliably loaded onto this substrate holder, and its Loading can also be carried out smoothly. The substrate will not fall off the substrate holder during transportation, and the substrate will not be unable to be transported due to poor dimensional alignment with various parts within the sputtering apparatus.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is assumed that the substrate holder according to the embodiment of the present invention has the same shape as that of the conventional example shown in FIG. However, the material is different and is made of titanium or a titanium alloy.

Next, in order to compare the characteristics of a substrate holder made of stainless steel, which is a conventional material, the internal stress of the material caused by heating will be explained first.

The cause of deformation due to heating is that when an integrated substrate holder is heated by thermal radiation, temperature unevenness occurs locally. Local temperature unevenness appears as a local thermal expansion difference, which generates internal stress within the material. When this internal stress exceeds the proof stress of the material, the substrate holder is plastically deformed.

The formula for the internal stress caused by the difference in thermal expansion is σ
It is expressed as =E×α×ΔT/2(1−ν). Here, σ
: generated internal stress, E: longitudinal elastic modulus, α: thermal expansion coefficient, ΔT: temperature difference, ν: Poisson's ratio.

Therefore, if the internal stress σ calculated by the above formula does not exceed the proof stress of the material, the material will not undergo plastic deformation due to heating even if there is a difference in thermal expansion within the same material.

[0018] High temperature parts of stainless steel and various titanium materials are 3
Table 1 below shows the temperature difference with the low temperature part where plastic deformation occurs when the temperature is around 00°C to 450°C.

[0019]

[Table 1]

As is clear from Table 1 above, titanium material does not undergo plastic deformation even when a large temperature difference occurs compared to stainless steel.

Furthermore, as mentioned above, it is clear that aluminum alloys are inferior to titanium materials at temperatures above 300°C, as estimated from the mechanical strength properties up to 200°C.

The above temperature range applies to PV indium tin oxide transparent conductive films for magnetic recording hard disks and liquid crystal display panels.
This temperature is sufficient for practical use as a temperature condition when forming a film by method D. Therefore, the values in Table 1 indicate that the titanium material has sufficient deformation resistance in the practical temperature range.

Next, a specific example of use as a substrate holder for film formation of a magnetic recording hard disk will be described.

When used as a magnetic recording hard disk, deformation of the substrate holder poses the following problems.

(1) It becomes impossible for the robot to mount the substrate on the substrate holder. (2) The substrate mounted on the substrate holder falls off during transportation. (3) When removing the substrate after film formation from the substrate holder, the robot cannot remove it. (4) Transporting the substrate holder The dimensions of the substrate holder and adjacent parts in the film forming apparatus in the middle of the transport path come to interfere with each other, making transport impossible.

[0026] The above defects can be solved by using aluminum alloy (JISA5
052 material) substrate holder and a titanium (Ti type 2) substrate holder were fabricated, a film formation test was conducted, and the incidence of defects was compared (test conditions = substrate holder temperature conditions during film formation; 350°C; fabricated. Board holder: Board outer diameter 5.
For 25 inches - Number of boards installed in one board holder: 9,
16 sheets for 3.5 inches, 25 sheets for 2.5 inches. Test board quantity: 10,000 pieces and over 6 months). Table 2 below shows the incidence of failure to mount the board, fall off of the board, and failure to remove the board, and Table 3 below shows the period of use until transport becomes impossible.

[0027]

[Table 2]

[0028]

[Table 3]

As is clear from Table 2 above, for magnetic recording hard disks of any size, the substrate holder made of titanium or titanium alloy of the present invention has a much lower incidence of defects in each characteristic. It becomes. In other words, compared to substrate holders made of aluminum alloy, the number of devices that cannot be mounted is significantly reduced from 0.12 to 0.02, from 0.14 to 0.03, and from 0.15 to 0.03%. Moreover, the number of things that fall off is zero. Furthermore, regarding non-removable items, the percentages for substrate holders made of aluminum alloy are 0.04, 0.06, and 0.07, while the percentages are 0.01, 0.01, and 0.01%, respectively, which are almost zero. close.

Furthermore, as is clear from Table 3, the period of use from when a board is mounted until it becomes impossible to transport is also shown in that the board holder made of titanium or titanium alloy of the present invention is much longer for hard disks of various sizes. It was a long period of time, almost twice as long.

Although the embodiments of the present invention have been described above,
Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, the case where a film is formed on a substrate by a sputtering method has been described, but the present invention is of course applicable to cases where a film is formed by other chemical or physical methods.

Further, in the above embodiments, the substrate holder of the substrate holder is circular in shape, but the present invention is not limited to this shape, and can be applied to all conventional substrate holder shapes. Applicable.

[0034]

Effects of the Invention As described above, according to the substrate holder of the present invention, the heating temperature for forming a film on the substrate is 300°C.
Even if it is above, there will be no plastic deformation, and therefore the robot will not be able to attach the substrate to the substrate holder, or the substrate attached to the substrate holder will not fall off during transportation, and the When removing the substrate from the substrate holder, there is no possibility that the robot will not be able to remove it. Furthermore, because the substrate holder is greatly deformed due to the dimensions of the parts and parts that are close to each other in the film forming apparatus during the transport process of the substrate holder, they do not interfere with each other, and the transport that was previously seen is no longer possible. Never. Furthermore, the period of use before it becomes impossible to transport can be made much longer than with conventional materials.

[Brief explanation of drawings]

FIG. 1 is a side view showing the relative positional relationship between a substrate holder and a robot according to an embodiment of the present invention.

FIG. 2 is an enlarged front view of the substrate holder in FIG. 1.

FIG. 3 is an enlarged sectional view taken along line [3]-[3] in FIG. 2;

FIG. 4 is a graph showing the temperature-yield strength characteristics of aluminum.

FIG. 5 is a graph showing the temperature-tensile strength characteristics of aluminum.

[Explanation of symbols]

1　Substrate holder

Claims (3)

[Claims] 1. A substrate holder for holding a substrate on which a film is to be formed in a heated atmosphere, the substrate holder being made of titanium or a titanium alloy. 2. The substrate holder is made of a thin plate and has a circular opening, a partial groove is formed at the lower circumferential edge of the opening, and the edge of the circular substrate is inserted into the groove. 2. The substrate holder according to claim 1, wherein the substrate holder is configured to hold the substrate in a standing position. 3. The heating temperature of the heating atmosphere is 300°C.
The substrate holder according to claim 1 or 2, which is the above.