TW201339341A - Film-forming method and sputtering apparatus - Google Patents

Abstract

The present invention uses a sputtering method to form a non-continuous coating film. The film-forming method according to the present invention is to carry out a film-forming treatment on a substrate by making the substrate and a sputtering target opposite to each other in a vacuum chamber and using a sputtering method to carry out the treatment. Furthermore, compared with the case of the surface temperature not reaching a predetermined temperature, a coating film having high electric resistance can be formed on the substrate when a manner that the surface temperature of the target reaches a predetermined temperature higher than ambient temperature is controlled.

Description

Film forming method and sputtering device

The present invention relates to a film forming method, and more particularly to a film forming method using a sputtering method and a sputtering apparatus.

As a film forming method for forming a thin film on a substrate, there are a vacuum vapor deposition method or a sputtering method. The vacuum vapor deposition method forms a thin film on a substrate by supplying a raw material to a crucible, a vapor deposition boat, or the like, and evaporating the raw material in a vacuum. On the other hand, in the sputtering method, particles which are scattered from the target are deposited on the substrate by sputtering the target to form a thin film on the substrate.

It is known that in these film forming methods, even if the film components are the same, the film quality is different. For example, in the case of a metal thin film, it is considered that the vacuum vapor deposition method is more likely to form a discontinuous film than the sputtering method (see, for example, Patent Document 1). Therefore, in order to form a discontinuous film, there is a tendency that the vacuum vapor deposition method is selected more than the sputtering method.

[Advanced technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2007-138270

However, the vacuum evaporation method is difficult to perform subtle control of the film thickness as compared with the sputtering method. Moreover, in the vacuum vapor deposition apparatus, the batch type is the mainstream, and the mass productivity is not good.

It is an object of the present invention to provide a non-continuous formation by sputtering A continuous film forming method and a sputtering apparatus.

According to an aspect of the present invention, there is provided a film forming method which is characterized in that a substrate is formed in a vacuum chamber to face a target and a film is formed on the substrate by sputtering, and The surface temperature of the target material is controlled to a temperature higher than a normal temperature, and a high-resistance film is formed on the substrate as compared with a case where the surface temperature of the target material is not higher than the specific temperature.

Further, according to an aspect of the present invention, a sputtering apparatus for realizing the above film forming method is provided.

According to the present invention, a discontinuous film can be easily formed by sputtering.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Before describing the film formation method, the film formation apparatus of this embodiment will be described first.

[Example 1]

Fig. 1 is a cross-sectional view showing a main part of a film forming apparatus. Fig. 1(a) shows the entire film forming apparatus 1, and Fig. 1(b) shows an enlarged view of the vicinity of the counter electrode 30 attached to the film forming apparatus 1. First, the outline of the film forming apparatus 1 will be described with reference to Fig. 1(a).

The film forming apparatus 1 is a sputtering apparatus and includes a vacuum chamber 10, a support table 20, and a counter electrode 30. Further, an anti-adhesive plate 11 is attached to the inner wall of the vacuum chamber 10 excluding the support table 20 and the counter electrode 30. In addition to this, filming The apparatus 1 is further provided with a supply pipe for supplying various gases into the vacuum chamber 10, and an exhaust pipe (not shown) for discharging the ambient gas in the vacuum chamber 10. A stopper 60 is provided on the support table 20.

The vacuum chamber 10 is a so-called vacuum container that maintains a reduced pressure state. A support table 20 is disposed on the bottom surface of the vacuum chamber 10, and a counter electrode 30 is disposed directly below the upper surface of the vacuum chamber 10. The support table 20 and the counter electrode 30 are arranged to face each other. The support table 20 holds the substrate 50, which is processed in the vacuum chamber 10. The counter electrode 30 is an electrode for discharging.

The anti-adhesive sheet 11 is, for example, a detachable replacement member made on the basis of a flat plate, and can be mounted in the vacuum chamber 10 or can be taken out from the vacuum chamber 10. By attaching the anti-adhesive sheet 11 to the inner wall of the vacuum chamber 10, it is possible to prevent the sputter particles from directly depositing on the inner wall of the vacuum chamber 10.

As the material of the vacuum chamber 10 and the anti-adhesive sheet 11, a metal such as iron, stainless steel or aluminum (Al) is suitable. Further, the vacuum chamber 10, the anti-adhesive plate 11, and the support table 20 are grounded.

Next, the structure of the counter electrode 30 will be described based on Fig. 1(b).

The counter electrode 30 includes, for example, a target 30t that faces the support table 20 side, a heating mechanism 30h that heats the target 30t, and a cooling mechanism 30c that cools the target 30t.

A heating wire and a temperature sensor (not shown) are provided in the heating mechanism 30h, for example. A medium flow path 30ch is formed in the cooling mechanism 30c, for example. The medium (for example, water, organic solvent, organic-containing water, heat transfer gas) can flow from the arrow A, flows through the medium flow path 30ch, and is discharged from the medium flow path 30ch as indicated by the arrow B. Thereby, the heat generated by the heating mechanism 30h is discharged to The heat of the cooling mechanism 30c is adjusted so that the surface temperature of the target 30t is adjusted.

Further, the surface temperature of the target 30t can be controlled by adjusting the spontaneous temperature rise during discharge and the medium temperature without using the heating mechanism 30h. For example, an external temperature regulator can be utilized to set the medium temperature to a temperature below normal temperature. Further, even if the heating means 30h is not used, the surface temperature of the target 30t can be set higher than the normal temperature by setting the temperature of the medium to be higher than normal temperature (for example, 22 ° C).

The heating mechanism 30h is covered by an insulating material. Thereby, it is ensured that the heating mechanism 30h is insulated from the target 30t or the heating mechanism 30h is insulated from the cooling mechanism 30c. Further, in order to perform magnetron sputtering, a magnet (not shown) may be provided on the back side of the counter electrode 30.

A power source 32 is connected to the counter electrode 30 via an insulating member 31. The power source 32 can be a DC power source or a high frequency power source (RF power source). Further, a protective thickness is formed between the side surface of the counter electrode 30 and the anti-adhesion plate 11 by the gap between the side surface of the counter electrode 30 and the anti-adhesion plate 11. Thereby, generation of plasma at the gap can be suppressed.

Furthermore, the installation position of the temperature sensor is not limited to the heating mechanism 30h, and may be provided in the cooling mechanism 30c. The surface temperature of the target 30t can also be measured using a radiation thermometer.

In order to explain in more detail the film forming apparatus 1 including the temperature adjusting mechanism of the targets 30t, a block diagram of the film forming apparatus is shown in FIG.

The film forming apparatus 1 includes the above-described power source 32, a cooling device 33 corresponding to the cooling mechanism 30c, and a heating device 34 corresponding to the heating mechanism 30h. Enter Further, the film forming apparatus 1 includes a gas supply source 36 for supplying a gas into the vacuum chamber 10, and a flow rate adjuster 35. A plurality of gas supply sources 36 may also be provided.

The power source 32, the cooling device 33, the heating device 34, and the flow rate adjuster 35 are controlled by a control unit (controller) 40 provided in the film forming apparatus 1.

For example, the measuring unit 40a detects the pressure in the vacuum chamber 10, the applied electric power (voltage, current, and application time), the surface temperature of the target 30t, the set temperature of the cooling device 33, the set temperature of the heating device 34, the gas flow rate, and the gas type. . Further, the temperature control unit 40b controls the cooling device 33 and the heating device 34. Thereby, the surface temperature of the target 30t is set to a specific temperature. Further, the discharge control unit 40c controls the power source 32. Thereby, the applied electric power (voltage, current, application time) is controlled. Further, the gas control unit 40d controls the pressure and the gas flow rate in the vacuum chamber 10 by, for example, feedback control. Further, when a plurality of types of gases are provided, the type of gas required for control is selected.

The surface temperature of the target 30t is adjusted by controlling the temperature of the cooling device 33 and the heating device 34, and also according to the air pressure in the vacuum chamber 10, the type of gas, the power applied to the target 30t, and the application of electric power to the target. Adjusted for film formation conditions at 30t. The relationship between the set temperature of the cooling device and the heating device, the film forming conditions, and the surface temperature of the target 30t can be determined in advance by experiments or the like. These correlations are stored in the storage unit 40e as a relationship table.

In this way, the film forming apparatus 1 of the present embodiment obtains the surface temperature of the target 30t, the set temperature of the cooling mechanism or the heating mechanism, the air pressure in the vacuum chamber 10, the type of gas, and the application to the target 30t. Electricity and The film forming conditions of the time when the power is applied to the target 30t, and the relationship between the material and shape (diameter, thickness, and aspect ratio) of the target 30t, and according to this relationship, the surface temperature of the target 30t reaches the desired temperature. Way to control.

Further, the correlation can be corrected based on the material and shape of the substrate 50. For example, a conversion table corresponding to the material of the target material 30t and the substrate 50 (semiconductor, glass, resin, etc.) is stored in the storage portion 40e.

Further, data may be input from the input unit 40f to the storage unit 40e as needed.

With this film forming apparatus 1, the surface temperature of the target 30t can be adjusted to a desired temperature regardless of whether it is formed in a film or not.

Further, the installation position of the support table 20 and the counter electrode 30 is not limited to the position shown in FIG. 1(a), and the support table 20 and the counter electrode 30 may be arranged upside down. Alternatively, the support table 20 and the counter electrode 30 may be disposed on the side surfaces of the vacuum chamber 10 so as to face each other.

The material of the target 30t is determined according to the composition of the coating formed on the substrate 50. For example, when the film formed on the substrate 50 is a film including tin (Sn), indium (In), silver (Ag), or an alloy or oxide containing at least one of them, the target 30t It is composed of a metal containing these metal components and alloy components.

Next, a film forming method using the film forming apparatus 1 will be described.

First, the pre-operation of the film forming apparatus 1 is performed before film formation is performed. In the pre-operation, the shutter 60 is closed, and the medium is caused to flow to the cooling mechanism 30c while the substrate is covered, and the heating mechanism 30h is driven. Further, plasma discharge is performed under specific conditions. At this time, the surface temperature of the target 30t is adjusted to a specific temperature by the above feedback control. The temperature is set, for example, to normal temperature to Within the range of the melting point of the target 30t.

When the interface between the target 30t and the heating mechanism 30h or the interface between the heating mechanism 30h and the cooling mechanism 30c is provided with an adhesive member (for example, In (indium)), the surface temperature of the target 30t may be set to a normal temperature to a viscosity. Within the range of the melting point of the connecting member.

If the heating means 30h can be used to ensure sufficient heat, the pre-operation can be omitted. Further, even if the shutter 60 is not disposed, the pre-operation can be performed by using the dummy substrate. Further, as for the temperature setting, the melting point of the member having the lowest melting point among the target member 30t, the bonding member, and other members may be the upper limit.

If the surface temperature of the target 30t is stable, the pre-run is ended and the shutter 60 is opened. That is, film formation is started. Then, when a film having a specific thickness is deposited on the substrate 50, the film formation is completed.

As described above, in the present embodiment, electric power is supplied to the counter electrode 30 provided in the vacuum chamber 10, and plasma is generated in the vacuum chamber 10, so that the target component is deposited on the counter electrode 30. On the substrate 50. Then, the surface of the target 30t can be heated to a normal temperature or higher to perform sputtering.

In the case where the surface of the target 30t is heated to a normal temperature or higher to perform sputtering, the film quality is changed when the surface of the target 30t is not heated to a normal temperature or higher and the film is sputtered. In the following description, a tin (Sn) film will be described as an example. However, in the present embodiment, it is not limited to the method of forming a tin film.

Figure 3 is a graph illustrating changes in film quality.

First, the horizontal axis of Fig. 3 is the order (sequence) of the film formation process, and the vertical axis is the sheet resistance (Ω/□) of the film, and the film formation conditions are as follows.

(film formation conditions)

Ambient gas = argon (Ar)

Pressure: 0.5 Pa

Discharge time: 160 seconds

Target: Tin (Sn) target, 3 inches in diameter

Discharge power: about 300 W

Film thickness: 250 nm

Medium temperature of cooling mechanism: 5 ° C, 22 ° C (normal temperature), 50 ° C

Further, a new substrate was prepared for each film formation process, and a film having substantially the same thickness was formed on the substrate. Further, for example, a 10-minute pause time is provided between the respective film formation processes.

First, the result of a case where the film formation process is started without performing the above-described pre-running, which is called cold start, will be described.

First, when the surface of the target 30t is not heated to a normal temperature or higher (medium temperature: 22 ° C), the sheet of the tin (Sn) film is electrically blocked at 1.0 × 10 in the first to fourth film formation. (Ω/□) or less. In the fifth film formation, the sheet resistance of the tin film was about 2.3 × 10 ² (Ω/□). Further, in the sixth film formation, the sheet resistance of the tin film was also about 1.6 × 10 ³ (Ω / □). As described above, when the surface of the target 30t is not heated to a normal temperature or higher, the sheet resistance of the tin film tends to be low.

On the other hand, in the case of heating the surface of the target 30t (medium temperature: 50 ° C), the sheet resistance of the tin film was about 2.6 × 10 ⁶ (Ω/□) in the first film formation. Then, in the second film formation, the sheet resistance of the tin film was increased to about 2.5 × 10 ¹¹ (Ω/□).

Next, the result of starting the film formation process by performing pre-running called hot start will be described. The pre-running is carried out for a continuous discharge of, for example, 30 minutes in accordance with the film formation conditions described above. Further, the target 30t was heated by a medium (medium temperature: 50 ° C).

In the hot start, the sheet resistance of the tin film has reached about 2.5 × 10 ¹¹ (Ω/□) at the time of the first film formation. Then, when the second and third film formations are stopped and the fourth film formation is attempted, the sheet resistance of the tin film is increased to about 5.0 × 10 ¹² (Ω/□). Here, the "suspended" in the hot start is a cycle in which the medium (50 ° C) is performed without discharging. Further, when the film formation of the fifth to tenth time is stopped and the film formation for the eleventh time is attempted, the sheet resistance of the tin film is maintained at about 9.9 × 10 ¹⁰ (Ω/□).

It can be seen that in any of the cold start and the hot start, the sheet resistance of the tin film is higher as the surface temperature of the target 30t is higher.

Further, it is understood that the higher the surface temperature of the target 30t, the more difficult it is to resist the resistivity of the tin (Sn) film depending on the time after the pre-run.

The reason is considered to be that the higher the surface temperature of the target 30t, the stronger the cohesiveness of the coating deposited on the substrate 50, and the more easily the coating is discontinuous in the direction substantially parallel to the main surface of the substrate 50 (island) ). That is, according to the present embodiment, the discontinuous film can be easily formed on the substrate 50 by the sputtering method. In other words, the electrical characteristics (for example, sheet resistance, electrical resistivity, etc.) of the film formed on the substrate 50 can be controlled in accordance with the surface temperature of the target 30t.

Further, the sputtering method can control the film thickness more easily than the vacuum vapor deposition method, and a finer film can be formed. Further, the sputtering apparatus can be assembled into a continuous apparatus, which is more excellent in mass productivity than the vacuum evaporation method.

In this way, the film formed on the substrate 50 is heated by heating the target 30t. The resistance rises in the case where the target 30t is not heated. The target 30t is heated by raising the temperature of the medium flowing in the counter electrode 30. In other words, by the sputtering method, a high-resistance and high-density film can be easily formed with high productivity.

Moreover, the discontinuous film of this kind has a weak metallic property and is close to insulation. As a result, the discontinuous film can easily pass through radio waves (for example, several MHz to several GHz), and can be used for a decorative film such as a mobile phone or a vehicle-mounted radar.

Such an effect can be obtained not only when tin is used as a coating material, but also, for example, using indium (In), silver (Ag), an alloy containing at least one of tin, indium, and silver, and containing tin, indium, and silver. This effect can also be obtained in the case where any of the oxides of at least one of them is used as a coating material.

Here, it is known that a discontinuous film can be formed by controlling (raising) the substrate temperature (for example, refer to Japanese Laid-Open Patent Publication No. 2001-26071, and Japanese Patent Laid-Open No. 2003-289005). However, with such a method, the mechanism for heating the substrate sometimes becomes complicated.

For example, when the target 30t having a diameter smaller than the substrate 50 is used, the support table 20 may be formed while being rotated to form a film to correct the unevenness of the film thickness. In this case, the support table 20 needs to include a rotary supply in addition to the heating supply, and the mechanism becomes complicated. Further, in order to uniformly form the discontinuous film on the substrate 50, it is necessary to control the temperature in the surface of the substrate, which makes the control supply complicated.

However, in the present embodiment, the discontinuous film can be easily formed on the substrate 50 simply by adjusting the surface temperature of the target 30t.

The above has been described with reference to the specific example 1 to the embodiment of the present invention. Description. However, the present embodiment is not limited to these specific examples. That is, those skilled in the art can appropriately design and change the above specific examples, and as long as they have the features of the present invention, they are also included in the scope of the present invention. For example, the heating of the target 30t may also illuminate the target 30t with light emitted from the heat lamp. Moreover, the respective elements included in the above specific examples, the formation, the materials, the conditions, the shapes, the dimensions, and the like are not limited to the examples, and may be appropriately changed.

Further, each element included in each of the above embodiments may be compounded within a technically feasible range, and combinations thereof may be included in the scope of the present invention as long as they have the features of the present invention.

In addition, what is obvious to those skilled in the art from the various modifications and modifications is also included in the scope of the inventive concept.

1‧‧‧ film forming device

10‧‧‧vacuum tank

11‧‧‧Anti-adhesive board

20‧‧‧Support Desk

30‧‧‧ opposite electrode

30c‧‧‧Cooling mechanism

30ch‧‧‧media flow path

30h‧‧‧heating mechanism

30t‧‧‧target

31‧‧‧Insulating components

32‧‧‧Power supply

33‧‧‧Cooling supply

34‧‧‧heating supply

35‧‧‧Flow Regulator

36‧‧‧ gas supply

40‧‧‧Control Department

40a‧‧‧Measurement Department

40b‧‧‧Temperature Control Department

40c‧‧‧Discharge Control Department

40d‧‧‧Gas Control Department

40e‧‧‧Storage Department

40f‧‧‧ Input Department

50‧‧‧Substrate

60‧‧‧ blocking

Fig. 1 (a) and (b) are cross-sectional views showing main parts of a film forming apparatus.

Figure 2 is a block diagram of a film forming apparatus.

Figure 3 is a graph illustrating changes in film quality.

1‧‧‧ film forming device

10‧‧‧vacuum tank

11‧‧‧Anti-adhesive board

20‧‧‧Support Desk

30‧‧‧ opposite electrode

30c‧‧‧Cooling mechanism

30ch‧‧‧media flow path

30h‧‧‧heating mechanism

30t‧‧‧target

31‧‧‧Insulating components

32‧‧‧Power supply

50‧‧‧Substrate

60‧‧‧ blocking

Claims (8)

A film forming method is characterized in that a substrate is formed in a vacuum chamber to face a target and a film is formed on the substrate by sputtering, and a surface temperature of the target is higher than a normal temperature. The temperature is controlled so that a high-resistance film is formed on the substrate as compared with a case where the surface temperature of the target is not brought to the above specific temperature. The film forming method of claim 1, wherein the surface temperature of the target is adjusted to the specific temperature before the film is formed on the substrate. The film forming method of claim 1, wherein the film is a discontinuous film. The film forming method of claim 1, wherein the target is heated by a method of heating a temperature of the medium flowing in the electrode including the target to a temperature higher than a normal temperature or by heating the target with a heating body. The film forming method of claim 4, wherein the surface temperature of the target, the medium or the set temperature of the heating body, the gas pressure in the vacuum chamber, the gas type, the electric power applied to the target, and the application are obtained. The relationship between the film formation conditions of the time when the power is supplied to the target, and the material and shape of the target are controlled such that the surface temperature of the target reaches the specific temperature according to the above relationship. The film forming method of claim 1, wherein the surface temperature of the target is adjusted within a range of a normal temperature or higher and a melting point of the material of the target. The film forming method of claim 1, wherein the film comprises an alloy selected from the group consisting of tin (Sn), indium (In), silver (Ag), and at least one of them. Or any of the group consisting of oxides. A sputtering apparatus characterized by being used for the film forming method according to any one of the above claims 1 to 7.