JPS6026660A - Control device for melt surface of source of evaporation - Google Patents

Abstract

PURPOSE:To monitor exactly the rise and fall of a melt surface and to perform control with high reliability by providing a monitor which senses the flying amt. of an evaporating material in addition to a monitor which controls the rate of evaporation in a treating chamber for vacuum deposition and controlling the supply of the evaporating material. CONSTITUTION:An evaporating material 5 is fed from a feeder 4 to a crucible 3b and is heated and melted by a coil 3a. A film deposited by evaporation is formed on a substrate 2 by the evaporating material from a source of evaporation 3. An atomic absorption type monitor 6 is provided near the substrate 2 to control the rate of evaporation from the source 3, by which the rate of evaporation is adjusted constant. A monitor 8 which senses the flying amt. of the evaporating material such as an atomic absorption monitor is provided in the position where the flying amt. of the evaporating material changes with the change in the melt surface is provided alongside the source 3. When the evaporating material that comes to fly attains a preset flying amt., the monitor senses the same and stops the operation of the feeder 4 for the material 5, thereby controlling the melt surface of the source 3 constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a melting surface control device for an evaporation source used in a vacuum evaporation apparatus.

Conventionally, this type of evaporation source continuously feeds wire-shaped or other evaporation material to a supply device as the melting surface decreases due to evaporation, thereby reducing fluctuations in the rate of evaporation, non-uniformity of the film components of the deposited film, or the evaporation source. It is necessary to prevent accidents such as damage due to dry heating, but if the drop in the melting surface is monitored directly optically through an optical sensor inserted into the vacuum chamber or through the window of the vacuum chamber, evaporation will occur. There is a drawback that the light emitting/receiving surface of the optical sensor and the window tend to fog up due to objects, and the supply device cannot be driven to supply evaporation. Also, if the evaporation source is of an induction heating type, the amount of heat applied to the coil will be increased.

It has also been proposed to detect the bias component and operate the feeder, but some of the evaporated material segregates in the melting hole, which disturbs the uniformity of the DO bias and makes it difficult to maintain the uniformity of the level of the melt surface. Currently, it is common practice to empirically judge the amount of evaporation from the evaporation source and to control the melting surface by intermittently operating the supply device using a timer. However, with this timer type, even if the supply amount is set empirically, a slight change in the melting level will change the uniform distribution surface of the evaporated material, so the planned film thickness will not be maintained, and the melting temperature will change and the product will be formed. It is difficult to detect an abnormal drop in the melting surface due to changes in the yield ratio of the membrane or damage to the evaporation source, which tends to result in a lack of reliability.

The purpose of the present invention is to eliminate such drawbacks and provide a highly reliable melting surface control device. In the case where the evaporation material is supplied by a supply device, an atomic absorption type monitor or other monitor is installed on the side of the evaporation source at a position where the amount of evaporation material changes as the melting surface changes. The present invention is characterized in that a monitor is provided to detect the amount of the evaporated material, and the supplying operation of the evaporated material of the supply device is stopped when the monitor detects the set flying amount.

An embodiment of the present invention will be described with reference to the drawings. (1) is a vacuum-evacuated processing chamber, (2) is a substrate provided above the chamber (1), and (3) is below the chamber (1). 2 shows an evaporation source provided facing the substrate (2), and the evaporation source (3) is, for example, connected to a coil (3a) in the form of a wire or powder in a supply device (4). ) supplied from evaporation material (5
) is melted by induction heating. The evaporation material evaporated from the evaporation source (3) adheres to the surface of the substrate (2) in the form of a film and is subjected to the evaporation process. Atomic absorption monitor (6) installed near the
The power of the coil (3m) is controlled by monitoring the evaporated material spreading in the shape of a flame according to the N-th power law, and the evaporation source (3)
By controlling the amount of evaporation from the

The above configuration is not particularly different from the configuration of a conventional vacuum evaporation apparatus, but the present invention is located at a position on the side of the evaporation source (3) where the amount of evaporated matter changes as the melting surface (7) changes. A monitor (8) such as an atomic absorption monitor, an electroluminescent monitor, or another monitor that detects the amount of evaporated matter is installed, and all evaporation sources (3) are connected so that the rate of evaporated matter is constant using the monitor (6) When the monitor (8) detects that the amount of flying evaporation material has reached the set amount, the operation of the supply device (4) for the evaporation material (5) is stopped, and the evaporation source is (3) The melting surface (7) is controlled to be constant to eliminate the above-mentioned disadvantages.

From the evaporation source (3), the spread according to the cosin N power law (
9), the lower part of the spreading moon 9) has an almost linear cross-sectional contour shape (11k), and the shape αQ
is a phenomenon in which the melting surface (descending and rising, contrary to the rise and fall of the force) occurs, and the area where the shape αQ on the side of the evaporation source (3) rises and falls and the flying of evaporated matter changes (JD monitor (
8) When the fc is provided, the rainbow melting surface (7) is located at the position (7a
) rises to the contour shape (l [If l falls, the monitor (
8) senses the evaporated matter and supplies the device (4) f! : Stop.

Further, when the melting surface (7) descends to the position (7b) and the contour shape (L (2) rises), the monitor (8) does not detect the evaporated material and the supply device (4) passes the evaporated material ( By repeating this process, the melting surface (7) is kept constant.

The contour shape (10) usually moves up and down centering on the upper part of the ruler (3b), but as shown in the third figure, a partition wall 0 is provided on the side and the shape α0 rises and falls with this as a boundary. A region (Iυ) may be formed.

(8a) (8b) When the light from the light source (8a) passes through the evaporated material, components of specific wavelengths are absorbed in the light source section and photodetection section that make up the Fi atomic absorption monitor (8). As the number of components detected by the photodetector (8b) decreases, the amount of the evaporated matter is sensed, and the monitor (6) also has a similar configuration. The power supply <14) is operated by the output of the monitor (8), and the feed motor is a feeder controller that performs the operation side 8 of one injection.

Does it work? To explain, when the molten surface of the evaporation source (3) becomes higher than the planned EL, the lower contour shape a of the evaporated material descends and reaches the monitor (8), and if the amount of the evaporated material exceeds the set value, the evaporated material is supplied. Device (4) is not activated.

The melting surface (7) is lowered and the contour shape becomes high 1 hamonitor (8).
), the supply device (4) supplies the rainbow evaporation material (5) to the evaporation source (3) according to the instructions of the monitor (8), raises the melting surface (7), and rises at the predetermined position (7a) t. Then, the monitor (8) detects the evaporated matter and stops the operation of the device (4), which is repeated. Also, if the melting surface (7) falls abnormally due to breakage of the melt (3b), the output from the monitor (8) will decrease, so the alarm or evaporation source (3) connected to this will decrease.
) can be activated.

The relationship between the output of the monitor (8) and the melting surface (the height of the force is the fourth
As shown in the figure, when the melting surface (7) reaches a high position (7a), the output of the monitor (8) becomes the output B which is larger than the set output A. ) is at a low position (7b), the output C becomes small and the supply device (
4) Activate.

In this way, according to the present invention, the monitor that controls the entire evaporation material supply device is installed on the side of the evaporation source at a position where the flying of evaporated material changes as the melting surface rises and falls, so that evaporated material does not adhere to the monitor. It is possible to reduce the number of times the monitor is cleaned, the rise and fall of the melting surface can be monitored relatively accurately, and the level can be maintained uniformly.

[Brief explanation of the drawing]

Figure 1 is a cutaway side view of an embodiment of the present invention, and Figure 2 is its
3 shows a modified example thereof, and FIG. 4 shows a relationship between the monitor output and the melting surface. (3)... Evaporation source (4)... Supply device (5)...
・Evaporation material (7)...Melting surface (8)...2 people outside the monitor

Claims (1)

[Claims] In a type in which wire-shaped or other evaporation material is supplied to the evaporation source by a supply device as the melting surface decreases due to evaporation from the evaporation source, the melting surface changes on the side of the evaporation source. An atomic absorption type monitor or other monitor for detecting the amount of flying evaporated material is provided at a position where the amount of flying evaporated material changes, and when the set amount of flying evaporated material is detected by the monitor, the operation of supplying the evaporated material of the supply device is stopped. Melting surface control device for evaporation source.