JP2002115051A - Bias sputtering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To normally apply bias voltage to a substrate even when sputtering is repeated many times in the sputtering for depositing a conductive film while applying the bias voltage to the substrate. SOLUTION: Gas such as argon is introduced in a sputter chamber 1 by a gas introducing system 2, voltage is applied from a sputter power source 4 to a target 3 formed of a conductive material to generate sputter discharge while holding the substrate 9 by a substrate holder 5. Sputter particles emitted from the target 3 reach the substrate 9 to deposit the conductive film. The bias voltage is applied to the substrate 9 by a bias power source 52. The substrate holder 5 has a holder shield 53 diagonally behind a substrate holding surface as a member of grounding electric potential, and a recess 54 for preventing film continuation so that a deposit film 501 on the surface of the holder shield 53 is not continuous to a deposit film 504 of the substrate holding surface. The substrate holding surface is smaller than the substrate 9, and the sputter particles on the recess 54 for preventing film continuation are shielded by a peripheral portion of the substrate 9 projected from the substrate holding surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus used for manufacturing an LSI (Large Scale Integrated Circuit) or the like.

[0002]

2. Description of the Related Art Sputtering apparatuses are widely used in various industrial fields as apparatuses for forming a thin film on the surface of an object. In particular, in the manufacture of various electronic devices such as LSIs, a sputtering apparatus is often used for forming various conductive films and insulating films.

FIG. 7 is a front sectional view showing a schematic configuration of a conventional sputtering apparatus. The apparatus shown in FIG. 7 is provided with a sputtering chamber 1 provided with an exhaust system 11, a gas introduction system 2 for introducing a predetermined gas into the sputtering chamber 1, and a sputtered surface exposed in the sputtering chamber 1. The target 3, a sputter power source 4 for generating a sputter discharge by setting an electric field in a space facing the surface to be sputtered of the target 3, and a sputter chamber 1 to which sputter particles emitted from the target 3 by the sputter discharge reach. It mainly comprises a substrate holder 5 for holding a substrate 9 at a predetermined position. When a gas such as argon is introduced by the gas introduction system 2 and a sputter discharge is generated by the sputter power supply 4, the target 3 is sputtered. The material released from the target 3 by sputtering reaches the surface of the substrate 9 and a thin film is formed.

In the above-described sputtering apparatus, a configuration in which a bias voltage is applied to the substrate 9 may be adopted for the purpose of improving the film quality or relaxing the film stress.
In many cases, the application of the bias voltage is based on a self-bias voltage generated by the high frequency and the plasma. Specifically, a portion 51 of the substrate holder 5 on which the substrate 9 is placed is made of a dielectric (hereinafter, this portion is referred to as a dielectric block),
A bias electrode is provided in a dielectric block. Then, a high-frequency power supply is connected to the bias electrode 52 as the bias power supply 6, and a high-frequency voltage is applied to the substrate 9 via the bias electrode 52.

When a sputter discharge is generated as described above, a plasma is generated between the target 3 and the substrate 9 by the discharge. On the other hand, when a high-frequency voltage is applied to the substrate 9, ions and electrons in the plasma are alternately and periodically generated.
However, since the mobility of electrons is much higher than that of ions, the potential change of the substrate 9 changes as if a negative DC voltage is superimposed on a high frequency. This negative DC voltage is the self-bias voltage. When sputtering is performed while applying a negative bias voltage such as a self-bias voltage, ions in the plasma enter the surface of the substrate 9 and bombard the surface. Therefore, there is an effect that the specific resistance and the like of the formed film are improved and the stress of the film is relaxed.

[0006]

In the conventional sputtering apparatus as described above, according to the study of the inventor,
It has been found that if sputtering is repeated until the number of processed substrates 9 reaches about several hundred, a problem occurs in which a bias voltage is not normally applied to the substrate 9. It was found that the improper application of the bias voltage deteriorated the quality and stress of the film to be formed and caused a product failure. The invention of the present application has been made in order to solve such a problem, and has a technical significance that a bias voltage is normally applied to the substrate 9 even when sputtering is repeated many times.

[0007]

In order to solve the above problems, the invention according to claim 1 of the present application is provided with a sputter chamber having an exhaust system and a sputtered surface exposed in the sputter chamber. A target made of a conductive material, a sputter power supply for setting an electric field in a space facing a surface to be sputtered of the target to generate a sputter discharge, and a predetermined position in a sputter chamber to which sputter particles emitted from the target by the sputter discharge reach. A substrate holder for holding the substrate and a bias power supply for applying a bias voltage to the substrate are provided, and sputtered particles from a target reach the surface of the substrate while applying a bias voltage to the substrate to form a thin film of the conductive material. In the bias sputtering apparatus, the front side of the substrate is the front side,
When the back side is the back side, the substrate holder has a member maintained at the ground potential obliquely behind the substrate holding surface, and further, the substrate holder is provided on the surface of the member maintained at the ground potential. It has a configuration in which a film for preventing film continuity is a concave portion for preventing a film to be deposited and a film to be deposited on the substrate holding surface from being continuous. According to a second aspect of the present invention, in order to solve the above-mentioned problem, in the configuration of the first aspect, the substrate holder comprises a metal holder main body and a dielectric block having a built-in bias electrode. The substrate holding surface is a surface of a dielectric block, and the member maintained at the ground potential is a holder shield for preventing discharge on the side of the dielectric block. In order to solve the above-mentioned problem, the invention according to claim 3 is the configuration according to claim 1, wherein the size of the substrate holding surface is smaller than the substrate, and the concave portion for preventing film continuity is provided. The structure is such that sputtered particles that are to reach the concave portion are provided at positions where they are shielded by the peripheral portion of the substrate protruding from the substrate holding surface. In order to solve the above problem, the invention according to claim 4 is characterized in that, in the structure of claim 1, the film deposited on the surface of the member maintained at the ground potential and the film deposited on the substrate holding surface are continuous. The width of the concave portion for preventing film continuity in the direction to be intended has a configuration of 0.5 mm or more. According to a fifth aspect of the present invention, in order to solve the above problem, the creeping distance from the surface of the member maintained at the ground potential to the substrate holding surface is 5 mm or more. Having a configuration. In order to solve the above-mentioned problem, the invention according to claim 6 is
In the structure of the first aspect, the distance between the edge of the opening of the concave portion for preventing film continuity and the substrate is 0.5 mm or more.

[0008]

Embodiments of the present invention (hereinafter, embodiments) will be described below. FIG. 1 is a schematic front sectional view of a sputtering apparatus according to an embodiment of the present invention. As in the apparatus shown in FIG. 7, the apparatus shown in FIG. 1 also includes a sputter chamber 1 provided with an exhaust system 11, a gas introduction system 2 for introducing a predetermined gas into the sputter chamber 1, and a sputter chamber 1 A target 3 provided so as to be exposed inside, a sputter power supply 4 for setting an electric field in a space facing a surface to be sputtered of the target 3 to generate a sputter discharge, and sputter particles emitted from the target 3 by the sputter discharge And a substrate holder 5 for holding the substrate 9 at a predetermined position in the sputtering chamber 1 where the substrate reaches.

[0009] The sputtering chamber 1 is an airtight vacuum vessel, which is electrically grounded. The exhaust system 11 is configured to exhaust the sputtering chamber 1 to about 10 ⁻⁵ to 10 ⁻⁷ Pa. Sputter chamber 1
Is hermetically connected to a transfer chamber (not shown) via a gate valve (not shown). The gas introduction system 2 introduces a sputter discharge gas such as argon into the inside at a predetermined flow rate. The gas introduction system 2 includes a gas cylinder (not shown) storing a gas for sputter discharge, and a valve 21 provided on a pipe connecting the sputter chamber 1 and the gas cylinder.
And a flow controller 22.

The target 3 is formed of a thin film material to be formed on the surface of the substrate 9. In the present embodiment, a conductive film of aluminum, copper, or the like is formed, so that the target 3 is made of these materials.
The target 3 is provided in the sputter chamber 1 so as to hermetically close the opening above the sputter chamber 1 via the insulator 31.
Attached to. The sputtering power supply 4 is configured to apply a predetermined negative DC voltage or high-frequency voltage to the target 3.

A magnet mechanism 7 is provided at a position facing the surface of the target 3 opposite to the surface to be sputtered. The magnet mechanism 7 includes a central magnet 71, a peripheral magnet 72 surrounding the central magnet 71, and a plate-like yoke 73 connecting the central magnet 71 and the peripheral magnet 72. The magnet mechanism 7 is provided to convert the sputter discharge into a magnetron discharge to perform efficient magnetron sputtering. That is, a magnetic field is formed in the vicinity of the target 3 by the magnet mechanism 7, and the electrons perform magnetron motion by the action of the magnetic field, thereby forming a plasma with higher density. As a result, the efficiency of the sputter discharge increases, and the substrate 9
The efficiency of film formation on the substrate also increases.

The substrate holder 5 holds the sputter chamber 1
It is mounted airtight. The substrate holder 5 has a trapezoidal shape, and the substrate 9 is placed on the upper surface. The substrate holder 5 mainly includes a metal holder main body 50 and a dielectric block 51 provided above the holder main body 50. In the dielectric block 51, a bias electrode 52 is provided as in the related art. Further, a bias power supply 6 for applying a high-frequency voltage to the bias electrode 52 to apply a self-bias voltage to the substrate 9 is provided.

The holder main body 50 is made of metal such as stainless steel and is short-circuited to the sputtering chamber 1.
Grounded. The line connecting the bias electrode 52 and the bias power supply 6 passes through the holder body 50, but is covered with an insulator (not shown), and the line and the holder body 50 are insulated. The substrate holder 5 may be provided with elevating pins or may be configured to move up and down as a whole in order to transfer the substrate 9 to and from a transfer robot (not shown) that transports the substrate 9. The substrate holder 5 may be provided with a configuration for heating or cooling the substrate 9. Further, a mechanism for electrostatically adsorbing the substrate 9 may be provided on the substrate holder 5. In this case, a configuration for applying a voltage for electrostatic adsorption to the bias electrode 52 is adopted.

A cylindrical deposition shield 81 is provided so as to surround the space between the substrate holder 5 and the target 3. The deposition prevention shield 81 prevents sputter particles from adhering to unnecessary places other than the surface of the substrate 9. It is inevitable that the sputtered particles emitted from the target 3 deposit a thin film not only on the surface of the substrate 9 but also on an exposed surface in the sputter chamber 1. If the deposition of the thin film on the exposed surface overlaps, the thin film may be peeled off due to internal stress or own weight. The peeled thin film becomes fine particles of a certain size and floats in the elementary sputtering chamber 1. When the fine particles adhere to the substrate 9, a shape defect such as minute projections may be formed on the thin film to be formed. Further, when a fine circuit is formed on the surface of the substrate 9 in advance, there is a possibility that a serious defect such as a circuit or a short circuit may occur due to the adhesion of the fine particles.

The fine particles that impair the quality of such treatment are:
Generally called "particles". In order to prevent generation of particles, a deposition prevention shield 81 is provided. It is inevitable that sputtered particles adhere to the deposition shield 81 and a thin film is deposited. However, the deposition shield 81 is configured to prevent the thin film from peeling, for example, by forming fine irregularities on the surface. I have. Even so, if the sputtering is repeated many times, peeling of the thin film is inevitable. Therefore, after a predetermined number of sputterings, the deposition-inhibiting shield 81 is replaced with a new one or a shield from which the thin film has been removed.

Now, in the sputtering apparatus of the present embodiment, in order to solve the above-mentioned problem, the configuration of the peripheral portion of the substrate holder 5 is modified. Hereinafter, this point will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view showing a configuration of a peripheral portion of the substrate holder 5 in the apparatus shown in FIG.

In the configuration of the substrate holder 5, both the holder main body 50 and the dielectric block 51 have a circular cross section in the horizontal direction. The holder body 50 and the dielectric block 51 are coaxial, but the diameter of the dielectric block 51 is slightly smaller than that of the holder body 50. Therefore,
As shown in FIGS. 1 and 2, the substrate holder 5 is in a state where a step is formed in a peripheral portion.

A holder shield 53 is provided so as to cover the step portion of the substrate holder 5. Since the holder shield 53 is made of metal and is in contact with the holder body 50, it is grounded. The surface of the substrate 9 held by the substrate holder 5 (the surface on which the film is formed)
Is the front side and the back side is the rear side, the holder shield 53 is positioned diagonally behind the substrate holding surface as shown in FIG.

The holder shield 53 is provided on the substrate holder 5.
This is for preventing unnecessary discharge in the peripheral portion of.
That is, since the holder main body 50 of the substrate holder 5 is grounded, no large electric field is formed between the sputtering chamber 1 and the container wall, which is also at the ground potential. An electric field generated by the bias power supply 6 or the sputtering power supply 4 is formed between the power supply 1 and the power supply 1. As a result, discharge may occur in this portion. When the discharge occurs, the surface of the dielectric block 51 may be sputtered to release particles, or the dielectric block 51 may be damaged. To prevent such a situation, the grounded holder shield 53
The peripheral surface of the dielectric block 51 is covered by this. still,
The holder shield 53 is a substrate holder 5 as a whole.
And a coaxial annular member, which covers a step formed by the holder body 50 and the dielectric block 51.

As shown in FIGS. 1 and 2, a holder shield 82 is provided so as to surround the dielectric block 51. As shown in FIG. Similarly, the holder deposition shield 82 also prevents spatter particles from adhering to unnecessary places. Protective shield for holder 82
Is to prevent spatter particles from adhering to the peripheral portion of the substrate holder 5 in particular.

As can be seen from FIG. 2, if the holder shield 82 is not provided, a large amount of sputtered particles adhere to the surface and outer surface of the holder shield 53, the outer surface of the holder body 50, and the like, and a film is deposited. If these deposited films are peeled off and become particles, they are close to the substrate 9 on the substrate holder 5 and thus easily stain the surface of the substrate 9. Therefore, the deposition of the film is suppressed by the deposition shield 82 for the holder. The holder deposition shield 82 is similarly configured to suppress the separation of the deposited film, and is replaced after a predetermined number of sputterings.

In order to suppress the film deposition on the peripheral portion of the substrate holder 5, it is preferable that the inner edge of the holder shield 82 and the peripheral edge of the substrate 9 be as close as possible. However, the holder shield 82
When the inner edge of the substrate 9 and the peripheral edge of the substrate 9 are close to each other, an adhesion phenomenon occurs in which the films deposited on the both come into contact when the film is formed by sputtering. When the adhesion phenomenon occurs, when the substrate 9 is removed from the substrate holder 5 after the end of sputtering,
Particles are likely to be generated due to peeling or breakage of the deposited film. Therefore, it is preferable that the inner edge of the holder deposition-inhibiting shield 82 and the peripheral edge of the substrate 9 be as close as possible to the extent that they do not adhere during a single film formation. This distance is
It is about 2 to 5 mm.

A major feature of the apparatus according to the present embodiment is that a concave portion 54 is provided around the substrate holder 5 so that the bias voltage can be normally applied to the substrate 9 normally. The concave portion 54 is provided for preventing a film from being continuously deposited between a member having a ground potential (here, the holder shield 53) existing around the substrate holder 5 and the substrate holding surface of the substrate holder 5. A concave portion (hereinafter, a concave portion for preventing film continuity) 54.

More specifically, the holder shield 5
A step is formed on the inner side surface of 3 as shown in FIG. Due to the step on the inner surface of the holder shield 53 and the side surface of the dielectric block 51, the concave portion 5 for preventing film continuity is formed.
4 are formed. The provision of the concave portion 54 for preventing film continuity is based on the research of the inventor as described below.

The inventor of the present invention, in the course of research on the bias voltage abnormalities occurring after repeating the above-described sputtering process many times, when the sputtering process is repeated many times, marks of abnormal discharge on the back surface of the substrate 9. Was found to be seen. FIG. 3 is a schematic view showing traces of abnormal discharge generated after repeating this sputtering process many times. As shown in FIG. 3, the abnormal discharge trace is a small round spot-shaped discolored portion (hereinafter referred to as an abnormal discharge spot).
91. The location where the abnormal discharge spot 91 occurs is not fixed, but often occurs near the periphery of the substrate 9 as shown in FIG.

The inventor has found that such abnormal discharge occurs
It was considered that the problem was caused by the occurrence of partial grounding of the substrate 9 to which the bias voltage was applied. Then, when a portion of the surface of the dielectric block 51 where the abnormal discharge spot 91 on the back surface of the substrate 9 was in contact was examined, deposition of a thin film was confirmed there. Then, it was confirmed that the thin film in that portion and the holder shield 53 were electrically connected.

From such knowledge, it is considered that the abnormal discharge is caused by the deposition of a thin film from the surface to the side surface of the dielectric block 51 and the holder shield 53, and the grounding of the substrate 9 through the thin film. Conceivable. This will be described in more detail with reference to FIG. FIG. 4 is a diagram illustrating the mechanism of occurrence of abnormal discharge. FIG. 4 shows a configuration in which there is no concave portion 54 for preventing film continuity unlike the embodiment shown in FIG.

As described above, in the process of repeating the sputtering process, the thin film is deposited not only on the surface of the substrate 9 but also on the surface of the deposition shield 82 for the holder. Further, as shown in FIG. 4A, the thin film 501 is also formed on the surface of the holder shield 53 by sputter particles entering from a gap between the inner edge of the holder deposition shield 82 and the peripheral edge of the substrate 9.
(Hereinafter, this thin film 501 is referred to as a shield deposition film).

Then, when the sputtering process is repeated, a shield deposition film 501 is further deposited, and in addition, FIG.
As shown in (2), a thin film 502 is also deposited on the side surface of the dielectric block 51 (hereinafter, this thin film 502 is referred to as a side surface deposited film). Also, when viewed microscopically, as shown in FIG. 4B, particles 503 of the same material as the material of the target 3 are also attached to the surface of the dielectric block 51 which is the substrate holding surface. Since the surface of the dielectric block 51 is covered by the substrate 9 during sputtering, the dielectric block 5
The particles on the surface of No. 1 (hereinafter, particles attached to the holding surface) 503 are hardly sputtered particles adhered during sputtering. The particles 503 attached to the holding surface are sputtered particles floating in the sputter chamber 1 even after the substrate 9 is removed from the substrate holder 5 after sputtering, and particles existing in the sputter chamber 1.

When the sputtering process is further repeated, as shown in FIG.
1 grows to make the film thicker, and the side surface deposited film 502 grows upward. At the same time, as shown in FIG. 4C, the adhesion of the holding surface adhering particles 503 overlaps on the surface of the dielectric block 51 and gradually grows into a thin film 504 (hereinafter, this film is referred to as a holding surface deposition film). ).

When the sputtering process is further repeated, as shown in FIG. 4D, the side surface deposited film 502 and the holding surface deposited film 504 are finally connected. Since these films 501, 502, and 504 are conductive films like the films formed on the surface of the substrate 9, as a result, the holding surface deposition film 504 is short-circuited to the holder shield 53, and the holding surface deposition film 504 is Becomes ground potential. In this state, when the substrate 9 is placed on the surface of the dielectric block 51 and sputtering is started while applying a bias voltage, the bias voltage is applied to the entire substrate 9 but the back surface of the substrate 9 Of these, a current suddenly flows to the holder shield 53 side from a portion in contact with the holding surface deposition film 504 short-circuited to the holder shield 53, and discharge occurs. As a result, the entire substrate 9 is also at the ground potential, and the bias voltage is eliminated.

An abnormal discharge spot 91 as shown in FIG.
Is considered to be a trace of a large current flowing due to partial concentration of the electric field by such a mechanism. And
In the abnormal discharge, the holding surface deposited film 504 is
In addition to the case where the film is completely connected to the film on the side surface of the above, it is considered that there is also a case where the two partially approach each other and a surface discharge occurs due to dielectric breakdown at the close portion. In any case, when such abnormal discharge occurs,
Since the substrate 9 is grounded, the bias voltage cannot be normally applied. As a result, intended effects such as improvement of film quality and relaxation of film stress cannot be obtained.

In the configuration of the present embodiment, based on such findings, a concave portion 54 for preventing film continuity as shown in FIG. 2 is formed. FIG. 5 is a diagram for explaining the function of the concave portion 54 for preventing film continuity. In the configuration of the present embodiment, FIG.
This shows a state where the sputtering process is repeated about the same number of times as the case shown in (4).

In the structure of this embodiment, when the sputtering process is repeated many times, a thick film is deposited on the surface of the holder shield 53 and the like as in the case shown in FIG. Here, as shown in FIG.
Even if 4 is deposited on the surface of the dielectric block 51, the holding surface deposited film 504
And the shield deposition film 501 do not continue. Therefore, the bias voltage does not become abnormal due to abnormal discharge or the like. Note that the step on the inner edge surface of the holder shield 53 extends 360 degrees circumferentially, and therefore the concave portion 54 for preventing film continuity also extends 360 degrees circumferentially.

In the shape of the concave portion 54 for preventing film continuity, the width of the opening (indicated by w in FIG. 2) is important for securing the separation between the holding surface deposition film 504 and the shield deposition film 501. It is preferable that the width w is such that the separation between the holding surface deposition film 504 and the shield deposition film is ensured even if the sputtering is repeated a sufficiently large number of times. As mentioned earlier,
In the sputtering apparatus according to the embodiment, periodic maintenance such as replacement of the holder deposition shield 82 is performed after a predetermined number of sputterings. Therefore, the “sufficient number of times” is, for example, the number of times until the regular maintenance (hereinafter, referred to as a maintenance interval), which is, for example, about 2000 to 4000 times.
The width w is preferably 0.5 mm or more so that the film is not continuous even if the sputtering is performed about this number of times.

Further, the depth of the concave portion 54 for preventing film continuity (FIG. 2)
(Shown by d in FIG. 3) becomes shallow, the film continuity preventing recess 54 may be filled with a thin film, and the film may be continuous. In order to prevent the film from being continuous even if the sputtering is performed about the number of times of the maintenance interval, the depth d
Is preferably 2 mm or more.

Next, the result of an experiment in which the effect of normalizing the bias voltage by the concave portion 54 for preventing film continuity was confirmed will be described. FIG. 6 is a view showing the results of an experiment in which the effect of normalizing the bias voltage by the concave portion 54 for preventing film continuity was confirmed. FIG. 6 shows a concave portion 54 for preventing film continuity as shown in FIG.
In the configuration without the and the configuration of the embodiment having the concave portion 54 for preventing film continuity, the sputtering process is repeated many times,
The result of measuring the internal stress of the formed thin film is shown.

The film forming experiment shown in FIG. 6 was performed under the following conditions. Pressure: 4 mTorr (about 0.5 Pa) Sputtering power supply 4: 600 V, 7 kW Bias power supply 6: 400 kz, 200 W Self-bias voltage: about 100 V

As shown in FIG. 6, the concave portion 54 for preventing film continuity
In the configuration without the above, the compressive stress of about -180 MPa (megapascal) is changed to the tensile stress from about 200 times, and reaches a little less than 600 MPa per 350 times. As a result, it is shown that the application state of the bias voltage has changed since about 200 times, which indicates that the reproducibility of the film formation has been greatly reduced.

On the other hand, in the structure having the concave portion 54 for preventing film continuity, the stress is stable at -180 MPa even when the sputtering process is repeated up to about 4000 times. This indicates that the bias power is always stable and normally applied. As described above, according to the configuration of the present embodiment, the ground voltage does not occur in the substrate 9 due to the deposited film, so that the bias voltage is normally and stably applied. For this reason, film formation with good reproducibility, in which film stress and film quality are always stable, can be performed.

The concave portion 54 for preventing film continuity also has the effect of preventing film continuity by increasing the creeping distance from the holder shield 53 to the substrate holding surface. That is, if there is no concave portion 54 for preventing film continuity and it is a mere flat surface, the holder deposition film 501 and the holding surface deposition 504 are formed.
And the amount of the sputtered particles required for the continuation of the process is small. On the other hand, if the concave portion 54 for preventing film continuity is present, the holder deposition film 501 and the holding surface deposition 504 will not be continuous unless the amount of the sputtered particles reaches a considerable extent. The creeping distance is preferably about 5 mm or more so that the film is not continuous even if the sputtering is repeated up to the number of maintenance cycles described above. In the experiment whose results are shown in FIG. 6, the creepage distance in the configuration of the embodiment having the concave portion 54 for preventing film continuity is about 10 mm. As understood from the above description, the “creeping distance” is a distance between a member at the ground potential such as the holder shield 53 and the substrate holding surface, and is a distance when the member traces the surface. is there.

In the structure of the present embodiment, as shown in FIG. 2, the size of the substrate holding surface of the substrate holder 5 is slightly smaller than that of the substrate 9. This configuration has the technical significance of further suppressing the continuity of the film with the grounding portion. That is, since the substrate holding surface is smaller than the substrate 9, the substrate 9
Are in a state of shielding sputtered particles that try to reach the concave portion 54 for preventing film continuity. For this reason, film deposition on the film continuity preventing recess 54 is suppressed, and the effect of preventing film continuity is further enhanced. On the other hand, when the substrate holding surface is the same or smaller than the substrate 9, the effect of shielding the sputtered particles by the substrate 9 is reduced, and the film is easily continuous.

The length of the protrusion of the substrate 9 from the concave portion 54 for preventing film continuity (indicated by L1 in FIG. 2) is 1 mm to 3 mm.
It is preferred that it is about. If it is smaller than 1 mm, the effect of shielding the sputtered particles becomes insufficient. Also, 3mm
If it is larger, a portion that does not contact the substrate holding surface becomes large, and there is a problem that the application of the bias voltage becomes uneven or insufficient.

The distance from the edge of the opening of the concave portion 54 for preventing film continuity to the substrate 9 (indicated by L2 in FIG. 2) is 0.5 m.
m or more. When L2 is smaller than 0.5 mm, as shown in FIG. 5, when the film 501 is deposited on the edge of the opening of the concave portion 54 for preventing film continuity, the film 501 comes into contact with the back surface of the substrate 9 so that the substrate 9 is grounded. This is because there is a risk of doing it.

The periphery of the substrate holding surface is chamfered as shown in FIG. This has the technical significance of preventing the back surface of the substrate 9 from being damaged and increasing the creepage distance. That is, as shown in FIG. 2, when the chamfering is performed to form a tapered surface, the creepage distance from the back surface of the substrate 9 to the holder shield 53 is longer than when the surface is perpendicular to the substrate 9. For this reason, the above-mentioned effect of preventing the continuity of the film can be further enhanced.

The concave portion 54 for preventing the film continuity may be formed by providing a step on the inner surface of the holder shield 53 or by making the inner surface of the holder shield 53 larger than the diameter of the side surface of the dielectric block 51. There may be a configuration in which a gap is provided between them. However, in the configuration of the above embodiment, the diameter of the inner surface of the holder shield 53 and the diameter of the side surface of the dielectric block 51 are precisely matched to fit the holder shield 53 into the dielectric block 51, and the positioning is performed by this. I am taking it. Therefore, when a gap is provided between the two, the holder shield 53 is attached to the holder body 50.
It is necessary to accurately position and fix the position.

As the configuration of the concave portion 54 for preventing film continuity, a circumferentially extending groove may be provided on the surface of the holder shield 53. In this case, the center of the circumference is coaxial with the axis of the substrate 9 or the substrate holder 5. In the above-described embodiment, the bias voltage is supplied from the high-frequency power supply, but may be supplied from a DC power supply. In the present invention, the thin film made of a conductive material is broader than a general concept and includes a semiconductor thin film such as silicon or gallium arsenide.

[0048]

As described above, according to the first aspect of the present invention, the concave portion for preventing film continuity is provided, so that the bias voltage can be normally applied even if sputtering is repeated many times, and The objectives such as relaxation of stress and improvement of film quality are sufficiently achieved. According to the second aspect of the present invention, since the member maintained at the ground potential is the holder shield, the above effect can be obtained while preventing discharge on the side of the dielectric block. According to the third aspect of the present invention, in addition to the above-described effects, the sputtered particles entering the concave portion for preventing film continuity are shielded by the substrate, so that the effect of preventing film continuity can be further enhanced. Also,
According to the fourth aspect of the invention, in addition to the above-described effects, the sputtered particles that are to enter the concave portion for preventing film continuity are shielded by the substrate, so that the effect of preventing film continuity can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view of a sputtering apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a configuration of a peripheral portion of a substrate holder 5 in the apparatus shown in FIG.

FIG. 3 is a schematic diagram showing traces of abnormal discharge that occur after repeating a sputtering process many times.

FIG. 4 is a diagram illustrating a mechanism of occurrence of abnormal discharge.

FIG. 5 is a view for explaining the function of the film continuity preventing recess 54, and shows a state in the case of repeating the sputtering process about the same number of times as that shown in FIG. Things.

FIG. 6 is a diagram showing the results of an experiment in which the effect of normalizing the bias voltage by the concave portion for preventing film continuity 54 was confirmed.

FIG. 7 is a front sectional view showing a schematic configuration of a conventional sputtering apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sputter chamber 11 Exhaust system 2 Gas introduction system 3 Target 4 Sputtering power supply 5 Substrate holder 50 Holder main body 51 Dielectric block 52 Bias electrode 53 Holder shield 54 Concavity for preventing film continuity 501 Shield deposition film 502 Side deposition film 504 Retention surface deposition film 6 Bias power supply 7 Magnet mechanism 81 Deposition shield 82 Deposition shield for holder 9 Substrate

Claims (6)

[Claims] 1. A sputter chamber having an exhaust system,
A target made of a conductive material provided so that a surface to be sputtered is exposed in a sputtering chamber; a sputter power supply for generating an electric field in a space facing the surface to be sputtered to generate a sputter discharge; A substrate holder for holding a substrate at a predetermined position in a sputtering chamber where sputtered particles emitted from the substrate reach, and a bias power supply for applying a bias voltage to the substrate, and sputtered particles from a target while applying a bias voltage to the substrate. In the bias sputtering apparatus for forming a thin film of the conductive material by reaching the surface of the substrate, when the front side of the substrate is the front side, and the back side is the rear side, the substrate holder is located at the ground potential obliquely behind the substrate holding surface. The substrate holder further comprises a member maintained at the ground. A film deposited on surfaces of the member maintaining the position, the bias sputtering device, characterized in that a film continuous prevention recessing a recess and film deposited on the substrate holding surface is prevented from continuously. 2. The substrate holder comprises a metal holder main body and a dielectric block having a built-in bias electrode. The substrate holding surface is a surface of the dielectric block, and the substrate holding surface is connected to the ground potential. 2. The bias sputtering apparatus according to claim 1, wherein the maintained member is a holder shield for preventing discharge on a side of the dielectric block. 3. The size of the substrate holding surface is smaller than that of the substrate, and the film continuity preventing concave portion is a peripheral portion of the substrate where sputtered particles trying to reach the film continuity preventing concave portion protrude from the substrate holding surface. 2. The bias sputtering apparatus according to claim 1, wherein the bias sputtering apparatus is provided at a position shielded by the bias. 4. A width of the film continuity preventing recess in a direction in which a film deposited on the surface of the member maintained at the ground potential and a film deposited on the substrate holding surface are continuous with each other is 0.5 mm.
2. The bias sputtering apparatus according to claim 1, wherein: 5. The bias sputtering apparatus according to claim 1, wherein a creeping distance from a surface of the member maintained at the ground potential to the substrate holding surface is 5 mm or more. 6. The bias sputtering apparatus according to claim 1, wherein a distance between an edge of an opening of the concave portion for preventing film continuity and a substrate is 0.5 mm or more.