JPH02221368A - Sputtering device - Google Patents

Abstract

PURPOSE:To keep the cooled state of a target constant and to prevent the variations in the quality of a formed thin film by monitoring the temp. of the target and controlling the amt. of a cooling medium to be supplied to the target cooling part in accordance with the target. CONSTITUTION:The target 2 provided with a target cooling part 3 is sputtered in a reaction chamber 1 to form a thin film on a substrate (non shown in the figure). In the sputtering device, the temp. of the target 2 is detected by an optical fiber-type fluorescence thermometer 12 having an optical fiber 13. A flow rate control valve 10 provided to a cooling water supply tube 8 is adjusted by a controller 14 in accordance with the detected temp., and the amt. of cooling water to be supplied to the cooling part 3 is controlled. Furthermore, the flow rate of cooling water is detected by a flowmeter 11 furnished to a cooling water discharge tube 9, a sputtering power source 17 is turned on or off, if necessary, through the controller 14, an alarm 15 and a timer 16, etc., and the temp. of the target 2 is raised or lowered. By this method, the cooled state of the target 2 is made uniform, and the quality of the thin film obtained is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering apparatus used for forming various thin films.

[Prior art] Sputtering has been used to form various thin films such as single thin films and compound thin films.These thin films have strong adhesion, good step coverage, small grain size, and uniform grain size. - Since it has excellent points such as
It is used in a wide variety of fields, including various electronic parts and decorative coatings. Particularly in recent years, reactive sputtering, in which sputtering is performed in a reactive gas, has been actively used to deposit various compound thin films 1, such as TiOa (titanium oxide), on substrates.

It is applied when forming ZnO (zinc oxide), etc.

Furthermore, it is also applied to the formation of various ferroelectric materials, high-temperature superconductor films, etc.

[Problems to be Solved by the Invention] By the way, when forming a thin film by the reactive sputtering method, it is difficult to grasp the optimal conditions, so there is a problem that the quality of the formed film tends to vary. The reason for this is that the film quality depends on many factors, such as sputtering power, oxygen partial pressure, and target cooling state when forming an oxide film.

Figure 4 is a graph showing the dependence of the sputtering rate f on the oxygen partial pressure when forming a Tie film as an example.The sputtering rate f on the target surface, normalized by the oxygen partial pressure, greatly depends on the oxygen partial pressure. are doing. This occurs because the target surface changes from metal to oxide as the sputtering reaction progresses, and is a factor that has a large effect on film quality. Similarly, if the cooling state of the target changes, the oxidation state of the target surface changes, which also has a large effect on film quality.

The present invention has been made in response to the above-mentioned problems.
The object of the present invention is to provide a sputtering apparatus that improves film quality.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a temperature detection means for detecting the temperature of a target, a cooling medium supply means for supplying a cooling medium to a target cooling section, and the temperature detection means. The present invention is characterized by comprising a supply amount control means for controlling the amount of cooling medium supplied by the cooling medium supply means in accordance with the temperature detected by the cooling medium supply means.

[Operation] The temperature of the target is constantly monitored, and when the temperature changes, this is detected and feedback control is performed to control the amount of cooling medium supplied to the target. As a result, the target cooling state can be kept constant, and the factors that change the film quality can be reduced, thereby improving the film quality.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the sputtering apparatus of the present invention, in which 1 is a reaction chamber (above the target) where a target 2, which serves as a source for forming a thin film, is placed together with a substrate to be sputtered (not shown). A target cooling section 3 is provided below. 4 is the target cover 5 is the insulator that floats the target cooling part from the ground 0-ring 6
sealed by.

A supply tube 8 and a discharge tube 9 for supplying and discharging water as a cooling medium are connected to the target cooling unit 3, and a flow rate adjustment valve 1o is provided in the middle of the supply tube 8, and a flow rate adjustment valve 1o is provided in the middle of the discharge tube 9. A flow meter 11 is provided.

An optical fiber type fluorescence thermometer 12 for detecting target temperature is connected to the side surface of the target 2 via an optical fiber 13. This fluorescent thermometer 12 can be a commercially available product, and a highly heat-resistant insulated probe coated with a fluorescent substance is used at the contact part of the optical fiber 13 with the target 2. The target temperature is constantly monitored by converting the light emitted by the fluorescent substance into temperature by guiding it through the optical fiber 13 without being affected. By setting an upper value A and a lower value B in the fluorescence thermometer 12 in advance, these A values can be set.

A range between 8 and 8 can be set as the optimum temperature.

When the fluorescence thermometer 12 detects a temperature other than the optimum temperature, a control signal is input to the controller 14, and the controller 14 controls the flow rate adjustment valve 10 and the alarm 15 to be driven. The flow rate supplied from the supply tube 8 to the target cooling unit 3 can be set in the range between these C and D as the optimum flow rate by setting an upper flow limit value C and a lower limit flow value in advance.

The alarm 15 operates to issue a warning to the surroundings and also starts a timer 16.6 timer 16
An arbitrary value t can be set in advance along with an optimal value E. The timer 16 operates to output a control signal to the sputtering power source 17 to stop its operation when a predetermined time has elapsed.

As a result, when the alarm 15 is driven, the sputter power supply 17 is turned off, and when the alarm 15 is not driven, the timer 16 is kept in a reset state, so the sputter power supply 17 remains on. Sputter power supply 1
When 7 is turned on, the target temperature increases, and when it is turned off, it decreases.

Next, the operation of this embodiment will be explained with reference to a flowchart.

(a) Temperature detection In FIG. 2, each time the temperature is detected by the fluorescent thermometer 12 in step a, it is determined whether the detected temperature T is higher than the upper set value A, and if it is higher, the flow moves to step Proceeding to step b, the flow rate regulating valve 10 is opened to increase the amount of water supplied. If it is low, the flow proceeds to step C where the detected temperature T is set to the lower limit set value B.
A determination is made as to whether or not it is lower than that. If low, the flow proceeds to step d, where valve 10 is closed to reduce the water supply, while if high, then A,
The flow returns to step a without any operation being performed since the temperature is maintained at the optimum temperature for 80 minutes. Thereafter, similar operations are repeated so that the target temperature is always maintained at the optimum temperature.

(b) Flow rate detection In FIG. 3, each time a flow rate is detected by the flow meter 11 in step a, it is determined whether the flow rate Q is greater than the upper limit flow value C. If there is a large number of
5 is driven, and if it is less, the flow proceeds to step C, where it is determined whether Q is less than the lower limit flow value. If the flow is low, the flow proceeds to step b and is operated as described above, while if the flow is high, the optimum flow rate between C and D is maintained, so the flow proceeds to step d, where the alarm 15 is not activated and further Proceed to step e, where the timer 16 is reset and return to step a.

When the alarm 15 is activated in step b, the flow proceeds to step f, where the timer 16 is started, and then the flow proceeds to step g, where it is determined whether the timer value t is greater than the set timer value E. It is done. If there is a large amount, the flow proceeds to step h, where the sputter power source 17 is immediately turned on.
is turned off, whereas if it is less, the flow returns to step a again.

Thereafter, similar operations are repeated until the optimum flow rate is secured and the controller 14 no longer outputs control signals to the flow rate adjustment valve 10 and alarm 15.

According to this embodiment, the target temperature is controlled to always be kept at the optimum temperature set in advance by the fluorescence thermometer 12, so that the target cooling state can be kept constant. Therefore, the factors that cause variations in film quality can be reduced.

This variation in membrane quality can be suppressed to a small level.

For example, when a ZnO film is formed according to this embodiment, in the past, as the temperature of the Zn target gradually increases, the state of the Zn target surface changes and the film formation rate decreases by about several to 10%. We were able to greatly improve this. Furthermore, even if the flow rate of the cooling water fluctuates due to rust or dirt in the tubes or fluctuations in the water supply pump pressure, this problem is eliminated because the target temperature is detected and fed back to the flow rate control using this embodiment. .

Similarly, feedback can be provided for changes in cooling water temperature. Furthermore, even if the sputtering conditions change by replacing the target laser with a new one, the target temperature remains constant, making it easier to continue sputtering in a constant state. As a result, variations in film quality have been reduced, making it possible to improve the reproducibility of the crystallographic and electrical properties of the film.

In this example, water was used as the cooling medium, but
The method is not limited to this, and other means such as gas or a heat exchanger can be selected. In addition, although we have shown an example of using a contact type optical fiber type fluorescence thermometer as a means of detecting the target temperature, it is also possible to directly detect the target temperature using a non-contact type such as an infrared radiation thermometer. can.

[Effects of the invention] This has been described above. According to the present invention, the target temperature is constantly monitored and the target cooling state is kept constant at -F, so that the causes of fluctuations in film formation are reduced and fluctuations in film quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the sputtering apparatus of the present invention,
FIGS. 2 and 3 are flowcharts explaining the operation of this embodiment, and FIG. 4 is a graph showing the dependence of sputtering rate on oxygen partial pressure. 1...Reaction chamber, 2...Target, 3...Target cooling section, 1
0......Flow rate adjustment valve. 11・・・・・・・・・Flow meter, 12・・・・・・・・・
・Optical fiber type fluorescence thermometer, 13... Optical fiber 14... Controller 15... Alarm, 16...・Timer 17...Sputter power supply.

Claims (1)

[Claims] a temperature detection means for detecting the temperature of the target; a cooling medium supply means for supplying a cooling medium to the target cooling section;
A sputtering apparatus comprising: supply amount control means for controlling the amount of cooling medium supplied by the cooling medium supply means in accordance with the temperature detected by the temperature detection means.