JPH0261059A - Vapor deposition apparatus - Google Patents

Abstract

PURPOSE:To stably attain the control of high vapor deposition rate with superior reproducibility by providing a hearth liner of a specific shape between an evaporation source and a hearth in an electron beam-heating-type vacuum vapor deposition apparatus. CONSTITUTION:At the time of vapor-depositing Al by means of an electron beam heating-type vacuum vapor deposition apparatus, a BN composite is formed as a hearth liner 4 on the internal surface of a hearth 1 made of Cu for Al evaporation used for heating and evaporating Al for vapor deposition by means of electron beam irradiation, in which Al 3 as an evaporation source is melted and evaporated. Since this hearth liner 4 has a shape in which thickness is continuously changed from side face toward the base and respective planes facing each other have spherical shapes, respectively, resonance hardly occurs in the vibrations generated in the molten Al 3 as the evaporation source, and further, concentration of stress is removed and cracking due to heat shock is prevented, and, as a result, the effects of improving and stabilizing the evaporation velocity of Al and prolonging the service life of the liner 4 can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vapor deposition apparatus used for forming thin films in the semiconductor field.

Conventional technology Electron beam heating vacuum evaporation allows extremely high power density to be applied to the evaporation source, making it possible to evaporate high melting point materials, which was not possible with resistance heating. Since the deposition material is dissolved in a water-cooled bath, it is known as a method that can stably deposit a high-purity film without any reaction with the hearth. However, since a water-cooled hearth is used, power efficiency decreases when evaporating materials with high thermal conductivity such as Al and Cu. For example, when evaporating Al, the cooling loss is around 80%, resulting in a high evaporation rate. To make it, melting with high power or a large-diameter hearth was necessary. Hearth liners have been considered as a method for improving such cooling loss, and hearth liners made of high melting point metals such as W and Ta, and ceramics such as BN (boron nitride) composites have been put into practical use and have been effective.

On the other hand, in an electron beam heated evaporation source, it is known that the energy of the electron beam causes a vibration phenomenon on the surface of the melted evaporation material.

This phenomenon often occurs when a highly insulating nose liner is used, and under certain conditions the vibrations can become resonant, especially in materials such as Mu1, which have a low density and a high boiling point relative to their melting point. The molten metal may become so violent that small balls of molten metal can be seen flying up.

In addition, when using a material that easily wets the liner material, such as a metal, during evaporation using the hearth liner, the liquid level of the molten metal may reach the red-hot upper edge of the hearth liner due to the above-mentioned vibration phenomenon. Since this artificially expands the evaporation area, the evaporation rate fluctuates rapidly, and when it exceeds a certain rate, it is difficult to continue evaporation at a stable rate.

A second problem with the conventional technology is that stress is applied to the ceramic hearth liner due to heat shock and thermal expansion of the evaporator, causing cracks in the liner. In particular, in commonly used hearth liners with the shape shown in Figure 3, stress concentrates along the boundary line where the bottom and side surfaces meet, causing cracks to occur in this area and, in severe cases, to melting from the cracked area. Ag oozed out and came into direct contact with the water-cooled hearth, reducing the insulation effect of the liner and causing rate fluctuations. In addition, in Fig. 3, 1 is a copper hearth, 2 is a hearth liner, and 13 is a person's hearth.
It's the source.

Problems to be Solved by the Invention The vibration phenomenon of the molten metal mentioned earlier is caused by the puff of the electron beam, the mass and viscosity of the molten metal, the shape and capacity of the liner, etc. When a resonance phenomenon occurs, the vibration of the molten metal surface changes periodically, etc. This phenomenon can be seen.

In particular, Ad has a high boiling point relative to its melting point, has a low viscosity in the evaporated state, and has a relatively small mass, so when it resonates, the amplitude of the molten metal surface is large and the molten metal may jump.

In addition, Al has good wettability with metals and reacts easily, so
It is impossible to use metal liners such as W, Cu, Ta, etc., and BN composite is known as a hearth liner material that is effective for Al. Jitsukō 61-20
No. 032 considers a method of improving the deposition rate by utilizing the shape effect of the BN composite d-liner.

However, ceramic hearth liners such as BN composites have the disadvantage of cracking due to stress concentration due to heat shock.

The present invention improves the drawbacks of the electron beam heating vapor deposition method described above, improves and stabilizes the evaporation rate when using a hearth liner, and extends the life of the liner, resulting in highly productive vapor deposition. This is what realizes the device.

Means for Solving the Problems In order to solve the above-mentioned drawbacks, the present invention provides a liner with a shape in which the thickness changes continuously from the side surface to the bottom surface.

Function: With this configuration, the hearth liner has a shape in which the thickness changes continuously from the side to the bottom, so the opposing surfaces are spherical, making it difficult for resonance to occur, and eliminating stress concentration. It can prevent cracking.

EXAMPLES The present invention will be explained below with reference to FIGS. 1 and 2.

FIG. 1 shows the mulch in a vapor deposition apparatus according to an embodiment of the present invention.
It is a figure which shows a part of the liner for vapor deposition. That is, copper
- A liner 4 having a different shape from the conventional liner is inserted into the base 1, and the Al liner 3 is placed therein. As shown in Figure 1, the thickness of the no-sliner 4 changes continuously from the side to the bottom, and since the opposing surfaces are spherical, resonance occurs and there is no stress concentration. , can prevent cracking due to heat shock.

When a hearth liner made of BN composite with the shape shown in Fig. 1 was made with 2R on the inside and evaporation was performed multiple times, the power of the electron beam at which the rate variation became large was 4,
It is 2KW, which is larger than the conventional shape's 3.7KW.

Furthermore, in order to obtain a rate of 6,000 students/course enrollment, the configuration shown in Figure 1 only requires an electron beam power of 3.5 KW, whereas the conventional configuration requires only 4.5 KW of electron beam power. ○KW power is required (see Figure 2).

In addition, the occurrence of cracks in the hearth liner has been reduced to 1 in the conventional case.
Cracking occurred after about 0 depositions, but by changing the shape, cracking no longer occurred even after 20 depositions.

Effects of the Invention By continuously changing the thickness of the hearth liner from the side to the bottom, the electron beam power at which the resonance phenomenon occurs can be increased from 3.7KW to 4.2KW, and the rate can be increased accordingly. The effect is also great.

In addition, the increased thickness improves the insulation effect, which allows a higher rate to be obtained with the same power.

Furthermore, by continuously changing the thickness, there are no points where stress is concentrated, and the occurrence of cracks due to heat cracks is suppressed.

Although the effect of the present invention has been explained using a spherical example, basically the same effect can be obtained with a shape that changes continuously.

As described above, the hearth liner of the present invention can stably control a high vapor deposition rate with good reproducibility, and a high-quality one is extremely advantageous in terms of productivity.
It is a dog of industrial and practical value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a part of a liner of a vapor deposition apparatus according to an embodiment of the present invention, Fig. 2 is a characteristic diagram of electron beam power-evaporation rate, and Fig. 3 is a sectional view of a conventional hearth liner. . 1... Copper hearth, 3... Ag source,
4... Hearth Liner!・・・-Multi-purpose hearth with I beam soil o (ni W)

Claims (1)

[Claims] A vapor deposition device in which a hearth liner is interposed between an evaporation source and a hearth, and the thickness of the hearth liner changes continuously from the side to the bottom.