JPH02163374A - Judging method for film thickness value in vacuum deposition - Google Patents

Abstract

PURPOSE:To accurately judge the maximum point and the minimum point of the read-in value locus of measured value by periodically measuring the thickness value of a vacuum- deposited film with a photoelectric photometer and judging the increase or decrease thereof and deciding a pole from the counter value of the times of increase or decrease. CONSTITUTION:Material is evaporated from an evaporation source 4 provided with a heater supporting base 5 in a bell jar 1 equipped with a vacuum system such as a rotary pump 9 and a thin film is vapor-deposited on a base plate 2. In the above-mentioned vacuum deposition, film thickness of the thin film on the base plate 2 is measured by projecting laser beams emitted from a laser beam radiating cylinder 13 and receiving beams with a photoelectric measuring instrument 14. This film thickness value is periodically measured and inputted into a computer 20 via an A/D convertor 15. Therein this measured value is once stored in a memory 23 and thereafter compared with a comparator 24. It is judged that this measured value is increased or decreased in comparison with the preceding measured value. The times of increase or decrease are counted with a counter 25 and this counter value is regulated so that this value is not made negative. When the counter value reaches the prescribed value, the pole of maximum or minimum is judged by decrease or increase tendency and an driver 27 of the evaporation source is controlled by a CPU 21.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for processing light intensity measurements of a photoelectric photometer in a vacuum evaporation control device.

(Prior Art) Conventionally, as technologies in this field, there have been the following, for example.

The light intensity measurement trajectory of the vaporized flat film during vacuum deposition using a photoelectric photometer is shown in FIG.

In the conventional vapor deposition control method, the maximum point Ma1 in FIG.
．． As a method of measuring Has = ·, Minimum point old + * Mil =, the luminous intensity value is measured periodically using a computer, and the maximum point, that is, when the luminous intensity measurement value is smaller than the previous value, and the minimum point, that is, , the formation status of the deposited film was measured by measuring when the luminous intensity measurement value became larger than the previous value. Here, multilayer deposited ZnS, hg
! ', the wavelength of the film is λ-550 nm.

(The invention attempts to solve this problem! II) However, when the signal from a photoelectric photometer is read by a computer through an A/D converter, if there is a noise component in the signal value, the above-mentioned local maximum and minimum points may be incorrectly determined. Put it away.

The present invention eliminates the problem of erroneous determination of maximum and minimum points due to noise as described above, and provides a film thickness in vacuum evaporation that allows accurate determination of maximum and minimum points of the reading trajectory of a photoelectric measuring instrument. The purpose is to provide a method for determining values.

(Means for Solving the !!I! Problem) In order to solve the above-mentioned problems, the present invention provides a method for determining a film thickness value in vacuum evaporation, in which the film thickness in vacuum evaporation is determined by measuring the light intensity of a photoelectric photometer. A step of periodically measuring a value, a step of determining whether the measured value has increased or decreased from a previously measured value, and the number of increases or decreases is counted by a counter so that the counter value does not become negative. At the same time, a step of determining that the peak point has reached a predetermined value is performed.

Here, if the measured value tends to decrease from the previously measured value, it is determined to be a local maximum point, and if the measured value tends to increase from the previously measured value, it is determined to be a local minimum point. .

(Function) According to the present invention, as described above, in the method for determining film thickness values in vacuum F and MM, it is determined whether the measured value read by the photoelectric photometer has increased or decreased compared to the previous value with respect to the measured value locus of the photoelectric photometer. If the number of increases and decreases reaches a certain value,
It is determined to be the maximum (81i small) point. Therefore, the state of vacuum deposition can be accurately monitored.

Therefore, the state of vacuum evaporation can be accurately detected and reverse vacuum evaporation control can be performed.

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

FIG. 1 is a system configuration diagram for determining the maximum point of a deposited film showing an embodiment of the present invention, FIG. 2 is a flowchart for determining the maximum point of the present invention, and FIG. 3 is a flowchart for determining the minimum point of the present invention. , and FIGS. 4 to 6 are explanatory diagrams of examples of determination of minimum points according to the present invention.

First, in FIG. 1, 1 is a valve +, 2 is a substrate, 3 is a shutter, and 4 is an evaporation source, that is, a plurality of evaporation sources in which various samples are placed on a rotating body (for example, ZnS, MgFr
5 is a heater support stand, 6 is an ionization vacuum gauge,
7 is a vacuum valve, 8 is a liquid nitrogen trap, 9 is a rotary pump, 10 is a two-way valve, 11 is a roughing pipe,
12 is a Pirani gauge, 13 is a laser beam radiation tube, 1
4 is a charging photometer that receives the light transmitted through the deposited film by the laser beam, 15 is an A/D converter, 20 is a computer, 21 is a CPU (central processing bag Tl), 22 is an input interface, 23 is a memory, 24 is a comparator, 25 is a counter, 26 is an output interface, and 27 is an evaporation source driver.

As shown in this figure, the vacuum evaporation apparatus basically consists of an exhaust system, evaporation W, 4. It is composed of a vacuum chamber such as a substrate 2 and a shack 3.

Here, the film thickness is measured by transmitting photometric data values to the computer 20 via the A/D converter 15 using the photoelectric photometer 14.
This is done by reading it periodically.

Then, it is determined whether the measured value has increased or decreased from the previously measured value, and if the number of increases or decreases reaches a certain value, it is determined that it is an extreme point, and the output interface 26 and the evaporation source driving device 27 The gonorrhea source 4 is rotationally driven through the evaporation source 4 to perform control such as switching the sample that has been used so far and performing evaporation with another evaporation source.

Hereinafter, with reference to the flowchart of FIG. 2, determination of the maximum point of the film thickness value (light intensity measurement value of a photoelectric photometer) in vacuum evaporation will be explained.

First, set the counter 25 to 0゛ (step Φ)
.

Next, the photometric data value from the photoelectric photometer 14 is read, that is, the film thickness value is read periodically as a "new film thickness value", and the value A11 is stored (step 2).

Next, the read value number at that time is stored in the memory 23 (step 2).

Next, the photometric data value Al from the photoelectric photometer 14 is read (step 2).

The measured data value A+z at that time becomes the "new film thickness value 2," and the measured data value AIl becomes the "old HAjγ value" (step ■).

Next, the measured data value All and the previous measured data value A8. is compared by the comparator 24, and the measured data value A1. is the previous measurement data 4e A I
+ or less, add 1 to the value of counter 25
(Step ■).

Next, the value of the counter 25 is determined, and if the value reaches a predetermined value (here, 5), it is determined as a local maximum point (step 2).

In step (3) above, if the measurement data input value 8 is greater than the previous measurement data value A++, the counter
Step ■) to make the value minus 1, and the counter 2
The value of 5 is determined, and the process returns to step (2) until the value becomes a constant value (here, 0) (step [phase]).

Also, in step 0 above, the value of the counter 25 is 0.
If there is no groove, keep the value at 0 (step 0),
Return to step (2) above.

Next, with reference to the flowchart of FIG. 3, determination of the minimum point of 12 thickness values (light intensity measurement values of a photoelectric photometer) in vacuum evaporation will be described.

First, set the counter 25 to O (step ■).
.

Next, the light [ff1. The photointensity measurement data value from the optical device 14 is read (step o).

Next, the read value Az+ at that time is stored in the memory 23 (
Step O).

Next, the photometric data set 〇 is read from the photoelectric photometer 14 (step O).

Measured data value A at that time! , becomes the “new film thickness value”, and the measured data value Az+ becomes the “old film thickness value °” (Step O)
.

Next, the measured data (11! Azz and the previous measured data value Δ2.
), the measured data value AI is the previous measured data value A t
+)), the value 41 of the counter 25 is set to plus 1 (step o).

Next, the value of the counter 25 is determined, and if the value reaches a predetermined value (here, 5), it is determined as a minimum point (step O).

In the above step [phase], if the measured data value Agz is smaller than the previous measured data value A□, the counter 2
The value of 5 is set to minus 1 (step O), the value of the counter 25 is determined, and the process returns to step 0 until the value reaches a predetermined value (here, 0) (step [phase]).

In addition, in the above-mentioned progressive ■, the value of the counter 25 is 0.
If there is no groove, hold the value at O (step ■
), return to step ◎.

Next, an example of determining the minimum point of the film thickness value (light intensity measurement value of a photoelectric photometer) in vacuum evaporation will be described with reference to FIGS. 4 to 6.

FIG. 4 shows the locus of the light intensity measurement value, and FIG. 5 shows an enlarged view of part a showing the details of the minimum point determination. Therefore, in Figure 5, the number of measurement points was increased to 13.
Then, as shown in Figure 6, the measured data value decreases up to measurement point 4, so the counter value is held at 0, and at measurement point 5, the measured data value increases and the counter value becomes 1. , at measurement point 6, the measurement data value decreases and the counter value becomes 0, at measurement point 7, the measurement data value increases and the counter value becomes 1, and at measurement point 8, the measurement data value decreases and the counter value becomes 0. At measurement point 9, the measurement data value increases and the counter value becomes 1. From then on, the measurement data value continues to increase, and at measurement point 13, the counter value reaches the predetermined value of 5, confirming an upward trend in the measurement data value. , is determined as a minimum point.

In this way, the maximum point or minimum point of the film thickness value in vacuum evaporation can be accurately determined and detected, so that accurate control of vacuum evaporation can be performed.

The vacuum thin @ film thus obtained is used as a vapor deposited film for cathode ray tubes, prisms, and the like.

Furthermore, the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, it is possible to accurately determine the maximum point and minimum point in the measured value of a deposited film using a photoelectric meter without misjudging it. . In particular, it is possible to reliably determine the extreme point even for signal values that include noise components. Further, according to the present invention, it is also possible to determine the extreme points of any signal value trajectory that continuously changes nonlinearly with respect to the time axis.

Therefore, the maximum point or minimum point of the film thickness value in vacuum evaporation can be accurately determined and detected, so that vacuum evaporation can be accurately controlled with high conversion.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a system for determining the maximum point of a deposited film showing an embodiment of the present invention, Fig. 2 is a flowchart for determining the maximum point of the present invention, and Fig. 3 is a diagram of determining the minimum point of the present invention. Flowchart, FIG. 4 is a diagram showing the trajectory of the luminous intensity measurement value in an example of determining the minimum point of the present invention, FIG. 5 is an enlarged view of part a of FIG. 4, and FIG. 6 is the minimum point determination of the luminous intensity measurement value FIG. 7 is a diagram showing a trajectory of light intensity measurement by a photoelectric photometer of a deposited film in conventional vacuum deposition. 14... Photoelectric photometer, 15... A/D converter, 20
...Computer, 21...CPU <Central processing bag, 22...Input interface, 23...Memory, 24...Comparator, 25...Counter, 26...
Output ink face. Patent applicant Oki° Electric Industry Co., Ltd. Agent Patent attorney Mamoru Shimizu (1 other person) Takumi Ya
(datn) Light 1 lotus - 哓り し た い my aR-n [Riki, tV ≥ 1 抛40
2 judgment theory E @ Figure 6

Claims (3)

[Claims] (1) (a) Periodically measuring the film thickness value during vacuum evaporation using the photointensity measurement value of a photoelectric photometer; (b) Determining whether the measured value has increased or decreased from the previously measured value. and (c) a step in which the number of increases and decreases is counted by a counter, the counter value is prevented from becoming negative, and when it reaches a predetermined value, it is determined to be an extreme point. How to judge. (2) The method for determining a film thickness value in vacuum evaporation according to claim 1, wherein if the measured value tends to decrease from a previously measured value, it is determined to be a maximum point. (3) The method for determining a film thickness value in vacuum evaporation according to claim 1, wherein if the measured value tends to increase from a previously measured value, it is determined to be a minimum point.