JP2001108615A - Atomic-absorption-type rate monitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an atomic-absorption-type rate monitor for accurately detecting the rate of an evaporation metal particle or the like for a long time regardless of the number, accurately controlling the rate, and individually and accurately detecting the rate at an arbitrary position. SOLUTION: In a device for monitoring the amount of metal particles by providing a light reception probe 10 on a light axis 13 from a light application probe 8 and absorbing light from the light application probe by the atom of the evaporation metal particle passing through a light absorption region 16 between the light application probe and the light reception probe, pipes 14 and 15 along the light axis are provided on each front surface of the light application probe and the light reception probe. A heating device 18 for preventing the adhesion of the metal particle is provided at an opening at the light absorption region side of a pipe, and the pipe is allowed to move freely in its axial direction and the distance of the light absorption region is controlled constantly. Further, another pipe is provided between the pipes, and a shutter 23 for controlling the passage of the metal particle at the light absorption region between the pipes is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling the thickness of a metal thin film formed on a substrate in sputtering or vapor deposition and controlling the process thereof by controlling the atom of sputtered metal particles or evaporated metal particles flying on the substrate. The present invention relates to an atomic absorption type rate monitor which absorbs light and detects the rate and amount of the metal particles based on the amount of absorption.

[0002]

2. Description of the Related Art Conventionally, this type of monitor is, for example, shown in FIG.
As shown in FIG. 5, a light irradiation probe e for irradiating light so as to traverse the evaporation path of the evaporated metal particles d from the evaporation source b of the vacuum film forming chamber a toward the upper substrate c, and receives light from the light irradiation probe e. A light receiving probe f is provided, the evaporation rate is monitored by the light receiving probe f, and an evaporation heat source g such as an electron gun is controlled by a control unit of a power supply h based on the received light intensity. ing. Windows i made of quartz or the like are provided in front of the light irradiation probe e and the light receiving probe f so that metal particles do not adhere to them.
A hollow cathode lamp k that emits light having a wavelength specific to the metal particles to be measured is used for the controller j, and light of this wavelength is absorbed when it collides with the metal particles. The light is received at a dependent light intensity, and the evaporation rate of the metal particles can be monitored.

[0003]

According to this atomic absorption type rate monitor, when the amount of metal particles is large, the amount of light absorbed in the evaporation path becomes large, the absorbance is saturated according to Lambert-Beer's law, and the accurate rate is measured. There is a disadvantage in that accurate control cannot be performed because of the inability to monitor the data. If the amount of the metal particles is large, the metal particles wrap around and adhere to the surface of the window i,
An accurate monitor cannot be performed due to the dirt on the window i.

It is an object of the present invention to provide an atomic absorption type rate monitor capable of accurately detecting the rate of sputtered metal particles or evaporated metal particles for a long time regardless of the amount, and performing accurate rate control. It is an object of the present invention to provide an atomic absorption type rate monitor capable of individually and accurately detecting the rates.

[0005]

According to the present invention, a light receiving probe is provided on an optical axis from a light irradiation probe, and sputtered metal particles or evaporated metal particles passing through an absorption region between the light irradiation probe and the light receiving probe. In a device for monitoring the amount of the metal particles by absorbing light from the light irradiation probe to atoms, by providing a pipe along the optical axis on each front surface of the light irradiation probe and the light receiving probe, To achieve the goal. The length of the pipe is preferably determined based on the relationship between the amount of the sputtered metal particles or the evaporated metal particles and the amount of light absorbed, and prevents the sputtered metal particles or the evaporated metal particles from adhering inside the pipe. A heating device for flowing a purge gas or preventing the sputtered metal particles or evaporated metal particles from adhering to the opening on the light absorption region side of the pipe is provided. By controlling to a constant, the above object can be achieved more accurately. By providing further pipes between the pipes and providing a shutter for controlling the passage of the metal particles through the light absorption area between the pipes, the rate can be individually and accurately detected at any position. Can be.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case in which an embodiment of the present invention is applied to a vapor deposition apparatus shown in FIG. 2 will be described. In FIG. Reference numeral 1 denotes an evaporation source provided below the substrate 3, reference numeral 3 denotes a substrate provided above the evaporation source 2, and reference numeral 4 denotes an evaporation source 5 of a metal material contained in the evaporation source 2 heated by a heating source 6 of an electron gun. A light irradiation probe 8 for irradiating light 9 traversing the evaporation path 7 from a controller 30 to detect the amount of evaporation (evaporation rate) of the evaporated metal particles; A light receiving probe 10 for receiving the light 9 was provided on the optical axis 13 of the probe 8, and the light irradiation probe 8 and the light receiving probe 10 were connected to a controller 30 having a power control function. A window 12 made of synthetic quartz is provided on the front surface of the light irradiation probe 8 and the light receiving probe 10.

The hollow cathode lamp 31 in the controller 30 irradiates light having a specific wavelength of the evaporated metal particles. When a part of the light traverses the evaporation path 7, the atoms of the evaporated metal particles are removed. Absorbed by the light receiving probe 1
0 is received. The light receiving intensity of the light receiving probe 10 depends on the density of the evaporated metal particles. When a signal corresponding to the light receiving intensity is input from the controller 30 to the power supply 11, for example, the heating source 6 is controlled so that the evaporation amount becomes constant. However, if the amount of the evaporated metal particles is large, the absorbance will be saturated as described above, or the inconvenience of escaping into the window 12 will be caused. These inconveniences are eliminated by providing pipes 14 and 15 along the optical axis 13 on the front surface of the light receiving probe 8 and the light receiving probe 10, respectively. The lengths of the pipes 14 and 15 are determined by predicting the relationship between the amount of evaporated metal particles and the absorbance thereof. For example, in the case of evaporated metal particles having a large amount of evaporation and a large absorbance, the distance of the light absorption region 16 is shortened. decide.

In the atomic absorption type rate monitor provided with the pipes 14 and 15 in FIG. 2, the relationship between the light absorbing region 16 and the evaporation rate and the light absorbance is as shown in FIG. When the width is as large as 500 mm, the saturation of the absorbance occurs at a lower rate than when the width is as narrow as 5 mm. By providing the pipes 14 and 15 with the distance α as in the present invention, the saturation can be raised to a high evaporation rate. it can. The amount of evaporation from the evaporation source 2 is measured by the intensity of the light received by the light receiving probe 10.
Since the light absorption region 16 to which the evaporated metal particles are irradiated with the light 9 is narrowed by 15, even if a large amount of evaporated metal particles evaporate from the evaporation source 2, only a part of the light passes through the light absorption region 16. Therefore, the absorbance is less likely to be saturated, and accurate measurement can be performed even with a large amount of evaporation. Also, pipes 14, 15
Is provided, the distance from the light absorption region 16 to the window 12 is increased, the amount of evaporated metal particles sneaking into the window 12 is reduced, noise is reduced, and measurement can be performed for a long time. In order to sufficiently prevent this wraparound, as shown in FIG. 3, a gas introduction pipe 17 connected to an external gas source is connected to the root of each of the pipes 14 and 15, and a purge gas such as an argon gas is supplied to this. preferable. The gas flow rate depends on the thickness of the pipes 14 and 15, but is a flow rate that does not affect the vapor deposition.

The evaporated metal particles from the evaporation source 2 are, as shown in FIG.
The deposited layer 1 adheres to the end surfaces 14a and 15a of the opening on the 6 side.
7, so that the distance α originally determined as the light absorption region 16 is reduced to the distance β, and the amount of the evaporated metal particles is reduced, giving a slight change in the absorbance, which prevents accurate measurement. It has been found. Therefore, FIG.
A heating device 18 such as an electric heater is attached near the opening on the light absorption region side of each of the pipes 14 and 15 to heat the vicinity of the opening of the pipe, and the evaporated metal particles adhering to the end faces 14a and 15a are re-used. By evaporating so that the deposited layer 17 is not formed thick, the distance α is maintained, and accurate monitoring can be performed. Specifically, when the distance α is 10
When the heating device 18 was not operated, a deposition layer 17 having a thickness of 3 mm was formed on the end face of each pipe when the heating device 18 was not operated.
When heated to 0 ° C., the deposited layer 17 remained at a thickness of 1 mm, and when the heating temperature was set to 500 ° C., almost no deposited layer 17 was generated.

Further, as shown in FIG. 6, each pipe is constituted by a double pipe having a slide portion 27, and the pipe is moved by a reciprocating linearly moving moving member 19 introduced from an actuator outside the film forming chamber 1. The portion 27 may be connected and moved, and in this case, even if the deposition layer 17 is formed, accurate monitoring can be performed while maintaining the distance α.
The slide section 27 can always maintain the constant distance α by automatically operating the actuator based on the degree of growth of the deposited layer 17 per unit time measured in advance.

For example, as shown in FIG. 7, a plurality of evaporation sources 2 are provided in the film formation chamber 1 to monitor the evaporation rate from each evaporation source, or to monitor the evaporation rates at a plurality of locations in the film formation chamber 1. When there is a demand for monitoring, one or more pipes 20, 21 and 22 are further interposed between the pipes 14 and 15 along the optical axis 13 as shown in FIG. The light-absorbing regions 16a, 16
b, 16c, and 16d, and shutters 23, 24, and 2 for controlling the passage of the evaporated metal particles to each light absorption region.
5 and 26 are provided. According to this configuration, the evaporation rate of each light absorption region can be individually monitored by alternately opening the shutters, and it is not necessary to provide many light irradiation probes and light reception probes. The film formation process can be controlled by monitoring a plurality of locations with a single monitor.

The monitor shown in the drawing irradiates light from the light irradiation probe 8 during the operation of the evaporation source 2, receives light not absorbed by the metal evaporation particles in the light absorption region 16 by the light receiving probe 10, and receives the light. This function monitors the evaporation rate based on the intensity. This function is the same as that of the conventional monitor. However, in the case of the present invention, pipes 14 and 15 are provided in front of the light irradiation probe 8 and the light receiving probe 10 so that the light absorption region 16
Is reduced, even if a large amount of evaporated metal particles are generated from the evaporation source 2, only a part of the generated metal particles pass through the reduced absorption region 16, so that the amount of light absorbed from the light irradiation probe 8 is reduced. Is less likely to saturate, and can be monitored with a light source having a small output even if the evaporation rate is high.
6 moves away, so that even if a large amount evaporates, the light irradiation probe 8
In addition, the amount of evaporated metal particles flowing into the light receiving probe 10 is small, and accurate monitoring can be continued for a long time. During this monitoring, the distance α of the light absorbing region 16 is maintained at a constant value by operating the heating device 18 provided on each pipe or by sliding the slide portion 27 so that the distance α of the light absorbing region 16 can be accurately determined. Can monitor the density of

In the above description, the example in which the evaporated metal particles are monitored has been described. However, the monitor of the present invention can also be applied to a case where a sputtering target is provided and the sputter rate of the sputtered metal particles is detected.

[0014]

As described above, according to the present invention, in a device for absorbing the light of a light irradiation probe to sputtered metal particles or vaporized metal particles and monitoring the amount thereof, a pipe is connected to the light irradiation probe. Since the light-absorbing region is narrowed by being provided on the front surface of the probe, the absorbance of light is less likely to be saturated and the amount of the metal particles can be monitored even when the amount is large. It has the effect of eliminating the inconvenience of wrapping around and adhering to the front,
By providing a heating device or a slide portion on the pipe, the distance of the light absorption region can be maintained during monitoring, and an effect of enabling accurate monitoring can be obtained. Also, by providing additional pipes between the pipes, a plurality of light receiving areas are formed between the pipes, and shutters are provided between them to alternately open and close them, so that the rates at different positions can be measured with one monitor. There is an effect that can be done.

[Brief description of the drawings]

FIG. 1 is a cutaway side view of a conventional atomic absorption type rate monitor.

FIG. 2 is a cutaway side view showing an embodiment of the present invention.

FIG. 3 is a sectional side view showing another embodiment of the present invention.

FIG. 4 is an explanatory view of a deposited layer attached to a pipe.

FIG. 5 is an explanatory view of a state in which a heating device is provided on a pipe.

FIG. 6 is an explanatory view of a state in which a slide portion is provided on a pipe.

FIG. 7 is an explanatory diagram of a configuration for monitoring a plurality of locations.

FIG. 8 is a diagram showing a relationship between an interval between light absorption regions and a saturated state of light absorbance.

[Explanation of symbols]

4 evaporated metal particles, 7 evaporation path, 8 light irradiation probe, 9 light, 10 light receiving probe, 13 optical axis, 14.
15.20.21.22 pipe, 16 absorption area, 1
8 heating device, 23/24/25/26 shutter,
27 slide part, 30 controller, 31 hollow cathode lamp,

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiharu Kurauchi 5-9-7 Tokodai, Tsukuba, Ibaraki Japan Inside Tsukuba Super Materials Research Laboratory, Japan Sky Technology Co., Ltd. 5-9-7 Nippon Masaki Technology Co., Ltd. Tsukuba Super Materials Laboratory F-term (reference) 2G059 AA01 AA05 BB08 CC03 EE01 FF06 GG10 JJ23 KK01 LL02 4K029 CA01 CA05 EA00

Claims (6)

[Claims] 1. A light receiving probe is provided on an optical axis from a light irradiation probe, and atoms of sputtered metal particles or vaporized metal particles passing through an absorption region between the light irradiation probe and the light receiving probe are irradiated with light from the light irradiation probe. An atomic absorption type rate monitor, wherein a pipe along the optical axis is provided on the front surface of each of the light irradiation probe and the light receiving probe in an apparatus for monitoring the amount of the metal particles by absorbing light. 2. The atomic absorption type rate monitor according to claim 1, wherein the length of said pipe is determined based on the relationship between the amount of said sputtered metal particles or evaporated metal particles and the amount of light absorbed. 3. An atomic absorption type rate monitor according to claim 1, wherein a purge gas for preventing the sputtered metal particles or the evaporated metal particles from adhering is flowed inside the pipe. 4. The apparatus according to claim 1, wherein a heating device for preventing the sputtered metal particles or the evaporated metal particles from adhering is provided at an opening of the pipe on the light absorption region side. Atomic absorption rate monitor as described. 5. The atomic absorption type rate monitor according to claim 1, wherein the pipe is movable in the axial direction so that the distance of the light absorption region is controlled to be constant. 6. A pipe is further provided between said pipes along said optical axis, and a shutter is provided for controlling said sputtered metal particles or evaporated metal particles to pass through an absorption region between said pipes. An atomic absorption type rate monitor according to any one of claims 1 to 5.