JP2002060937A - Sputter film deposition system, and film deposition method using the sputter film deposition system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high throughput without causing an increase in cost and deterioration in film quality in sputter film deposition. SOLUTION: The sputter film deposition system has the following components inside a vacuum chamber 1: a target cover 3a for holding a target 3; a rotatably provided polygonal carousel wafer holder 2 for holding a plurality of wafers W1 on the sides; and a guide-bar-fixing jig 8a for holding a plurality of film thickness correction guide bars 8 made of metal in such a way that they can be disposed between the target 3 and the wafer W1 facing each other. The fixing jig 8 holds the guide bars 8 detachably. Further, the number of the guide bars 8 to be used and also the position of insertion, i.e., the interval of arrangement of the guide bars 8 can be arbitrarily selected according to film deposition conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputter film forming apparatus having a carousel mechanism for expanding a film forming region having a uniform film thickness distribution, and a film forming method using the sputter film forming apparatus. .

[0002]

2. Description of the Related Art Conventionally, when a stable film having a higher packing density than that of a vapor deposition method is formed, a sputtering method may be employed.

[0003] However, the number of substrates that can be formed by one film formation by the sputtering method is very limited, and as a result, the cost has been increased. For products whose quality is the highest priority over cost, such as optical films for steppers, it is unavoidable to sacrifice the cost to some extent, but for general applications, for example, optical thin films such as dichroic mirrors, the highest priority is given to cost. Is a task to be done. Therefore, a film formation method devised for improving the throughput is a method called a carousel type. This method has a mechanism that holds the substrate on the side surface on the outer periphery of the polygonal drum and rotates in the circumferential direction of the rotating drum around the rotation axis,
The sputtering process can be performed continuously, and the film formation cost can be reduced.

In a sputter film forming apparatus having such a carousel mechanism, variation in optical characteristics in the rotating direction (film unevenness) can be made relatively small, but the carousel must be rotated in a direction perpendicular to the rotating direction. It is difficult to eliminate the unevenness of the film quality or the like by using only the above. Therefore, to correct the film thickness, insert a film thickness correction plate so as to partially cover the target surface and optimize its shape to achieve uniform film quality, or target the carousel holding the substrate The film unevenness was eliminated by a method of giving a certain angle to the film.

[0005]

However, the following two problems are mainly involved in the method of homogenizing the film quality by inserting a film thickness correction plate.

The first problem is that the plasma atmosphere itself is changed by inserting such a film thickness correction plate into the plasma atmosphere, and the film forming conditions are apt to fluctuate.

As a second problem, when deciding the shape of the film thickness compensating plate, a number of film thicknesses are taken into consideration in consideration of the distribution of the film thickness and the fluctuation of the plasma atmosphere due to the inserted film thickness compensating plate. This is a method in which a thickness compensating plate is actually manufactured and a test is performed, so that a great deal of labor and time are required to find an optimal shape.

Accordingly, an object of the present invention is to provide a sputter film forming apparatus capable of achieving a high throughput without increasing the cost or lowering the film quality, and a film forming method using the sputter film forming apparatus. Things.

[0009]

In order to achieve the above object, a sputter film forming apparatus according to the present invention comprises a substrate holding member which rotates while holding a substrate on which a thin film is to be formed, and a target inside a vacuum vessel. In a sputtering film forming apparatus having a target holding member for holding, the respective bar members are detachably attached so that a plurality of bar members for controlling a film thickness distribution are arranged between the target and the substrate. It has a bar holding member for holding.

In the sputtering film forming apparatus of the present invention configured as described above, a plurality of bars for controlling the film thickness distribution are arranged between the target and the substrate by the bar holding member. In the case of a rod, since the influence on the plasma atmosphere is smaller than that of the type using a plate member for controlling the film thickness distribution, the change in the plasma atmosphere itself is suppressed, and the rod is held on the rotating substrate holding member. It is possible to suppress a change in the film formation conditions for the substrate that has been set. In addition, since each bar is detachably held by the bar holding member, the number and arrangement interval can be easily changed, whereby the film thickness can be changed without modifying the apparatus according to the film forming conditions. Can be easily controlled to improve the uniformity.

Further, the bar holding member may hold each bar such that a longitudinal direction of each bar is substantially parallel to a tangent in a rotation direction of the substrate holding member.

A film forming method according to the present invention is a film forming method for forming a thin film on a substrate by using the sputtering film forming apparatus according to the present invention, characterized by including a step of changing the number of the respective bars. I do.

The film forming method of the present invention as described above uses a sputter film forming apparatus in which a bar holding member detachably holds a plurality of bars for controlling the film thickness distribution. Since the step of changing the number of materials is included, film forming conditions can be easily optimized.

Further, the method may include a step of changing the arrangement interval of each bar.

[0015]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of an example of a sputtering film forming apparatus used for forming a multilayer optical thin film according to an embodiment of the present invention.

The sputtering film forming apparatus includes a target 3 in a decompression chamber 1 evacuated by a vacuum pump (not shown).
, A polygonally rotatable carousel substrate holder 2 that holds a plurality of substrates _{Wl on} which thin films are formed on its side, and a plurality of metal film thickness correction guide rods 8. has opposing target 3 and the guide rod fixing jig 8a for fixing and holding to be placed between the substrate W _l, also, RF power source 4 and the DC frequency voltage and a DC voltage to the target 3 Power supply 5
Ar in the decompression chamber 1 is a sputtering gas.
Ar and O ₂ introduction lines 6 for introducing gas and O ₂ gas which is a reactive gas, and H ₂ for introducing moisture into the decompression chamber 1.
O introduction line 7.

Each of the film thickness correction guide bars 8 is arranged so that its longitudinal direction is parallel to a tangent in the direction of rotation of the carousel substrate holder 2 indicated by an arrow A in FIG.

The carousel substrate holder 2 shown in FIG.
It has a prismatic shape, can hold six substrates _Wl on its side surface, and can rotate in the direction of arrow A. Note that the shape of the carousel substrate holder 2 is not limited to a hexagonal prism shape, and may be a polygonal shape having six or more surfaces. In this case, the number of substrates _Wl to be held may be six or more. Needless to say.

FIG. 2 is a three-view drawing of the guide rod fixing jig 8a. A plurality of holes 10 into which the film thickness correction guide rods 8 are inserted are formed in the guide rod fixing jig 8a, and a plurality of screw holes 11 are orthogonal to each of the holes 10.
Are formed.

Next, FIG. 3 shows a state in which the film thickness correction guide rod is fixed to the guide rod fixing jig.

FIG. 3 is a view of the target 3 viewed from the substrate _Wl side. A pair of guide rod fixing jigs 8a are provided on both sides of the target 3. Guide rod fixing jig 8a
Are arranged so that the guide rod fixing jig 8a is parallel to the rotation direction of the carousel substrate holder 2 indicated by the arrow A.

After the guide rod 8 is inserted into the hole 10 of the guide rod fixing jig 8a, it is fixed by screwing a screw (not shown) into the screw hole 11. Note that the number of used film thickness correction guide rods 8 and the insertion position, that is, the arrangement interval can be arbitrarily selected according to the film formation conditions. In order to prevent the film from sticking,
A screw is screwed in and sealed as in the case of fixing.

The high-frequency voltage of the RF power supply 4 is applied to the target 3 via the matching network 4a, and the DC voltage of the DC power supply 5 is applied to the target 3 via the low-pass filter 5a.

[0025] Next, steps of forming an oxide film on a substrate W _l.

First, the substrate W is placed on the carousel substrate holder 2.
_After decompression chamber 1 is depressurized to a predetermined degree of vacuum, Ar gas and O ₂ gas are introduced from Ar and O ₂ introduction line 6, and H ₂ O is introduced from H ₂ O introduction line 7, and target 3 the applied at least one of the DC voltage of the high-frequency voltage or a DC power source 6 of the RF power source 4 to generate plasma P ₁ by the so-called magnetron sputtering discharge.

The target 3 is sputtered by positive ions of the plasma P ₁ and partially oxidized by oxidizing active species near the surface of the target 3 toward the rotating substrate W ₁ on the carousel substrate holder 2. Released. At that time, the target 3 near the optimal number of thin film formation and the movement of the particles by the film thickness correcting guide rod 8 which has been made by the array is disturbed partly deposited on the substrate W _l on carousel substrate holder 2 The amount of particles is controlled.

[0028] Thus, the sputtered particles reaching the a controlled deposition amount with the substrate W _l is oxidized by the oxidation active species in the vicinity of the surface of the plasma P _l or during substrate W _l, oxide thin film substrate It is formed on the surface of the W _l.

As described above, according to the sputtering film forming apparatus of the present embodiment, since the area where the film thickness correction guide rod 8 covers the target 3 is smaller than the method using the film thickness correction plate, the plasma P ₁ The effect on the atmosphere is small,
A change in the plasma atmosphere itself is suppressed, and a change in film forming conditions for the substrate held by the rotating substrate holding member can be suppressed.

Further, the control for improving the uniformity of the film thickness can be easily performed by changing the number and the arrangement interval of the film thickness correction guide rods 8, so that not only the film thickness fluctuation can be easily predicted but also the apparatus can be easily controlled. Film formation can be performed under various film formation conditions without modification.

Although the present invention has been described by taking the above embodiments as an example, the present invention is not limited to these embodiments. Examples of the above-described embodiment will be described below, but the present invention is not limited to these examples.

[0032]

FIG. 4 shows a state in which a film thickness correction guide rod is attached to a guide rod fixing jig in the sputter film forming apparatus used in this embodiment. In the sputter film forming apparatus used in this embodiment, the number of sets of the film thickness correction guide rod 8 of the guide rod fixing jig 109 shown in FIG. 4 is smaller than that of the guide rod fixing jig 9 shown in FIG. The configuration is basically the same as that of the sputter film forming apparatus described in the above-described embodiment except that the number of the set film thickness correction guide rods 8 is different. The reference numerals used in the description of the above embodiment are used.

The guide rod fixing jig 109 is capable of setting 21 film thickness correction guide rods 8, 5, 6, 8, 9, and 9.
A total of nine film thickness correction guide rods 8 were set in the holes 10 of Nos. 13, 15, 17, 19 and 20. The diameter of the set thickness correction guide rod 8 is φ3 mm, and the material is metal Al.

The dimensions of the Ti target 3 are 127 mm ×
381 mm, and BK7 which is an optical glass having a diameter of 30 mm was used as the substrate Wl.

A DC power supply 5 having a capacity of 5 kW was used, and the pressure inside the decompression chamber 1 was reduced to 0.8 Pa to form a film. (Comparative Example) In the apparatus used in the above-described embodiment, a film was formed under the same conditions as in the above-described embodiment except that the film thickness correction guide rod 8 was not set on the guide rod fixing jig 109.

FIG. 5 shows the physical film thickness of the thin film formed using the film thickness correction guide bar in the embodiment and the physical film thickness of the thin film formed without using the film thickness correction guide bar in the comparative example. Fig. 4 shows a graph comparing? The film thickness shown in the graph is from the film thickness correction guide rod 8 set in the fifth hole 10 to the film thickness correction guide rod 8 set in the twentieth hole 10 shown in FIG. It shows the physical film thickness of the film formed up to this point.

As can be seen from the graph of FIG. 5, it was confirmed that a uniform film thickness was formed by setting the film thickness correction guide rod 8 at the optimum position. In the examples, it was also confirmed that the optical film thickness represented by the product of the refractive index and the physical film thickness had sufficient uniformity.

[0038]

As described above, according to the present invention, since a plurality of rods having a small effect on the plasma atmosphere are arranged between the target and the substrate, a change in the plasma atmosphere itself is suppressed. Variations in film forming conditions with respect to the substrate held by the rotating substrate holding member can be suppressed, and the number of bars and the arrangement interval can be easily changed to improve the uniformity of the film thickness. Control can be easily performed. Therefore, in a sputter deposition apparatus having a carousel mechanism, a large amount of optical thin films having excellent optical characteristics can be stably obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of a sputtering film forming apparatus used for forming a multilayer optical thin film according to an embodiment of the present invention.

FIG. 2 is a three-view drawing of a guide rod fixing jig in the sputter film forming apparatus of the present invention.

FIG. 3 is a view showing a state in which a film thickness correction guide rod is fixed to the guide rod fixing jig shown in FIG. 2;

FIG. 4 is a view showing a state in which a film thickness correction guide rod is attached to a guide rod fixing jig in the sputter film forming apparatus used in the embodiment of the present invention.

FIG. 5 is a graph comparing the thickness of a thin film formed using a thickness correction guide bar with the thickness of a thin film formed without using the thickness correction guide bar.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Decompression chamber 2 Substrate holder 3 Target 3a Target cover 4 RF power supply 4a Matching network 5 DC power supply 5a Low-pass filter 6 Ar, O ₂ introduction line 7 H ₂ O introduction line 8 Film thickness correction guide rod 9 Guide rod fixing jig 10 Hole 11 Screw hole

Claims (4)

[Claims] 1. A sputter film forming apparatus comprising: a substrate holding member that rotates while holding a substrate on which a thin film is to be formed; and a target holding member that holds a target inside a vacuum vessel. And a bar holding member for detachably holding each of the bars so that a plurality of bars for controlling the film thickness distribution are arranged between them. 2. The sputter according to claim 1, wherein the bar holding member holds the bars so that a longitudinal direction of each bar is substantially parallel to a tangent of a rotation direction of the substrate holding member. Film forming equipment. 3. A film forming method for forming a thin film on a substrate by the sputter film forming apparatus according to claim 1 or 2, comprising a step of changing the number of the respective bars. Film formation method. 4. The film forming method according to claim 3, further comprising a step of changing an arrangement interval of each bar.