JP2003007643A - Film-forming processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film-forming processor, capable of forming desired unformed film portions and uniformizing the influence of a clamp ring on a work for forming a uniform film. SOLUTION: The clamp ring 24 has a contact part 124, having random micro- irregularities formed by, e.g. blasting a part which faces the outermost peripheral part of a semiconductor wafer 1 on the downside of the ring body 126. The contact part 124 expands over the entire peripheral zone of a width d1, at a distance d2 from the inside edge of the ring body 126; the distance d2 may, e.g. be about 1-3 mm and the width d1 may, e.g. be about 1 mm. The ring body 126 faces the wafer 1 with a constant distance Rmax of, e.g. 1.6 μm or less, in parts other than the contact part 124.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus, and more particularly to a film forming apparatus having a structure of a contact surface of a clamp ring for holding a peripheral edge of an object to be processed with the object to be processed.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, for example, CVD (Chemical Vapor) is used for the purpose of forming an integrated circuit on the surface of a semiconductor wafer such as silicon.
A thin film is formed using a Deposition device.

In such a film forming process, it may be necessary to avoid forming a film on the peripheral portion or the back surface of the semiconductor wafer. For example, CVD is performed by using a film forming gas such as WF ₆ gas to bury tungsten in the contact hole.
This is the case when processing is performed.

In this case, since W (tungsten) has poor adhesion to SiO ₂ formed on the peripheral portion and the back surface of the semiconductor wafer, when the W film adheres to the SiO ₂ film, it is easily peeled off, particles are generated, and semiconductor wafers are generated. This is because it causes pollution.

Therefore, when forming a film on a conventional semiconductor wafer, for example, a peripheral edge is covered with a clamp ring, and a film forming gas is slipped into a gap between the clamp ring and the semiconductor wafer to form a film. A method has been proposed in which the distance is kept to a very small interval.

FIG. 8 is a schematic plan view from the side of the conventional clamp ring semiconductor wafer, and FIG. 9 is a sectional view showing the positional relationship between the conventional clamp ring and the semiconductor wafer. Figure 8
As shown in 9 and 9, the conventional clamp ring 3 has a ring body 5 and a contact portion 7.

The ring body 5 has, for example, a trapezoidal cross section,
The outer circumference is outside the outer circumference of the semiconductor wafer 1, and the inner circumference is
It is formed inside the outer periphery of the semiconductor wafer 1 and covers the peripheral portion of the semiconductor wafer 1. The contact portions 7 are formed on the surface of the ring body 5 facing the semiconductor wafer at equal intervals, for example, six pieces, for example, in the shape of a rectangular parallelepiped, and come into contact with the semiconductor wafer 1 to connect the ring body 5 of the clamp ring 3 and the semiconductor wafer 1. It is configured to maintain a minute constant interval h such that no film is formed therebetween.

[0008]

By the way, in the case of forming a film by using the film forming apparatus equipped with such a clamp ring 3, the semiconductor wafer 1 is heated from the lower part of the semiconductor wafer mounting table and, for example, WF ₆ gas is used. A W film is formed on the surface of the semiconductor wafer by introducing a film forming gas such as the above from the upper part of the processing chamber of the film forming apparatus toward the semiconductor wafer and exhausting the gas from the side of the processing chamber.

However, the clamp ring 3 is intermittently contacted with the semiconductor wafer at the outer peripheral portion of the semiconductor wafer by the plurality of contact portions 7, and the heat of the semiconductor wafer is radiated from the clamp ring 3, whereby the temperature of the semiconductor wafer is increased. There was a problem that the distribution became non-uniform and the film formation rate became non-uniform.

Further, in order to prevent the film formation due to the processing gas flowing around to the back surface and the peripheral portion of the semiconductor wafer, even when the purge gas is made to flow as shown by the arrow F in FIG. There was a problem that the flow of was uneven.

The present invention has been made in view of the above problems of the conventional film forming apparatus, and an object of the present invention is to form a film on a peripheral portion and a back surface of a semiconductor wafer and to remove a clamp ring. Another object of the present invention is to provide a new and improved film forming apparatus having a clamp ring that prevents the film from peeling off and does not unevenly affect the temperature distribution on a semiconductor wafer.

[0012]

In order to solve the above problems, according to the present invention, in a film forming processing apparatus for performing a film forming process on a processing surface of an object to be processed, a peripheral edge of the processing surface of the object to be processed. The clamp ring is provided with a clamp ring for clamping the portion, and the clamp ring has a contact portion that makes full contact with the object to be processed at a peripheral portion of the object to be processed, and an inner peripheral side of the contact portion, or an object to be processed on the inner peripheral side and outer peripheral side. There is provided a film forming apparatus in which the processing surface is provided with a facing portion facing each other at a predetermined interval, and the contact portion is provided with a random fine uneven surface.

The clamp ring has a continuously formed convex portion having a contact portion that makes a full contact with the object to be processed at the peripheral edge of the object to be processed, and a processing surface of the object to be processed at the inner peripheral side of the contact portion. And a facing portion facing each other at a predetermined interval,
The contact portion may be formed with a random fine uneven surface. Random fine irregularities can be formed by blasting.

With this structure, it is possible to prevent unnecessary film formation due to the circling of the processing gas to the outer peripheral portion and the back surface of the object to be processed, and to prevent the film from peeling off when the clamp ring is removed, and to evenly affect the object to be processed. Thus, it is possible to perform film formation accurately.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to the accompanying drawings,
A preferred embodiment of the film forming apparatus according to the present invention will be described in detail. In the present specification and drawings,
For components having substantially the same functional configuration,
The duplicated description is omitted by attaching the same reference numerals.

FIG. 1 is a sectional view showing a film forming apparatus using a clamp ring according to the present invention. Here, as an example of the processing apparatus, W which is a film gas having a strong corrosive property
A film forming apparatus for depositing a tungsten film using F ₆ gas will be described.

As shown in FIG. 1, the film forming processing apparatus 2 has a processing container 4 which is formed of aluminum or the like into a cylindrical or box shape. In the processing container 4, a mounting table 10 is provided on a cylindrical reflector 6 standing upright from the bottom of the processing container 4 via, for example, an L-shaped holding member 8. The semiconductor wafer 1 as the object to be processed is mounted on the mounting table 10.

The reflector 6 is made of, for example, aluminum for the purpose of reflecting the lamp light. Holding member 8
Is made of a material having low thermal conductivity, such as quartz, for the purpose of blocking the mounting table 10 from thermal conduction. Table 10
Is made of, for example, a carbon material or an aluminum compound such as AlN having a thickness of about 1 mm.

Below the mounting table 10, a plurality of, for example, 3
Book lifter pins 12 are provided upright on a circular ring-shaped support member 14. By moving the support member 14 up and down by a push-up rod 16 provided through the bottom of the processing container 4, the lifter pin 12
The semiconductor wafer 1 can be lifted by inserting it into a lifter pin hole 18 penetrating the mounting table 10. The lower end of the push-up bar 16 is connected to an actuator 22 via a bellows 20 that is expandable and contractable in order to maintain an airtight state inside the processing container 4.

Clamp ring 24, which is a feature of the present invention
Are provided on the periphery of the mounting table 10 for holding the semiconductor wafer 1 and fixing it to the mounting table 10. The clamp ring 24 has a substantially ring shape along the contour shape of the semiconductor wafer 1, and is made of, for example, ceramic. Details of the shape will be described later.

The clamp ring 24 is connected to the support member 14 via a support rod 26 that penetrates the holding member 8 in a loosely fitted state. As a result, the lifter pins 12 can be moved up and down together with the lifter pins 12. The coil spring 28 is interposed between the holding member 8 and the supporting member 14, and the clamp ring 2
It assists the lowering of 4 etc. and secures the clamping of the semiconductor wafer 1. The lifter pin 12, the support member 14, and the holding member 8 are made of a heat ray transmitting member such as quartz.

The transparent window 30 is airtightly provided at the bottom of the processing container 4 directly below the mounting table 10 via a seal member 32 such as an O-ring. The transmission window 30 is formed in a disk shape as a whole and is made of a heat ray transmission material such as quartz. Specifically, for example, a transparent plate 34 made of quartz glass and alumina (A
The protective film 36 is made of a l ₂ O ₃ ) crystal film.

The box-shaped heating chamber 38 is provided below the transparent window 30 so as to surround the transparent window 30. Heating chamber 3
A plurality of heating lamps 40 as heating means are provided in
It is attached to a turntable 24 that also serves as a reflecting mirror. The rotary table 24 is rotated by a rotary motor 44 provided at the bottom of the heating chamber 38 via a rotary shaft. The heat ray emitted from the heating lamp 40 passes through the lamp transmission window 30 and irradiates the lower surface of the mounting table 10 to heat it.

A ring-shaped straightening plate 48 having a large number of straightening holes 46 is provided on the outer peripheral side of the mounting table 10, supported by a support column 50 which is formed in a ring shape in the vertical direction. The attachment 52 is made of quartz in the shape of a ring and is provided on the inner peripheral side of the current plate 48 in contact with the outer periphery of the clamp ring 24 so that gas does not flow therebelow.

An exhaust port 54 is provided at the bottom of the rectifying plate 48, and an exhaust path 56 connected to a vacuum pump (not shown) is connected to the exhaust port 54. As a result, the inside of the processing container 4 is maintained at a predetermined degree of vacuum. The gate valve 58 is provided on the side wall of the processing container 4, and the semiconductor wafer 1
It is opened and closed when loading and unloading.

On the other hand, the shower head section 60 includes the mounting table 1
It is provided on the ceiling of the processing container 4 facing 0, and the processing gas is introduced from here. The shower head portion 60 is, for example, a head body 6 formed of aluminum in a circular box shape.
2, and a gas introduction port 64 is provided in this ceiling portion. The gas introduction part 64 includes, for example, WF ₆ , Ar, S
A gas source of a gas necessary for processing iH ₄ , H ₂ , N ₂ or the like or a cleaning gas source of ClF ₃ or the like is connected via a gas passage so that the flow rate can be controlled.

In the lower part of the head body 62, a large number of gas ejection holes 66 are arranged substantially in the plane, and the gas supplied into the head body 62 is discharged over the surface of the semiconductor wafer in the processing space S. To do. A diffusing plate 70 is arranged in the head body 62. The diffusion plate 70 has a large number of gas dispersion holes 68 and supplies gas more uniformly to the semiconductor wafer surface.

Next, a film forming method performed by using the film forming apparatus having the above structure will be described. First,
The gate valve 58 provided on the side wall of the processing container 4 is opened, and the semiconductor wafer 1 is loaded into the processing container 4 by the transfer arm. At this time, the lifter pin 12 is pushed up to transfer the semiconductor wafer 1 to the lifter pin 12 side.

Subsequently, the push-up rod 16 is lowered to lower the lifter pins 12, the semiconductor wafer 1 is placed on the mounting table 10, and the push-up rod 16 is further lowered to press the peripheral edge of the semiconductor wafer 1 against the clamp ring 24. Then fix it.

Next, a required gas from WF ₆ , Ar, SiH ₄ , H ₂ , and N ₂ is supplied as a processing gas from a processing gas source (not shown) to the shower head portion 60 by a predetermined amount and mixed. The gas injection hole 6 on the lower surface of the head body 62
It is evenly supplied from 6 into the processing container 4.

At the same time, the internal atmosphere is sucked and exhausted from the exhaust hole 54 to set the inside of the processing container 4 to a predetermined degree of vacuum, and the heating lamp 40 located below the mounting table 10 is rotated and driven. And radiates heat energy.

The radiated heat rays are transmitted through the transparent window 30 for the lamp.
After passing through, the back surface of the mounting table 10 is irradiated and heated. Since the mounting table 10 is very thin with a thickness of about 1 mm, it is heated quickly, and the semiconductor wafer 1 mounted thereon can be heated quickly to a predetermined temperature. The supplied mixed gas causes a predetermined chemical reaction, and, for example, a tungsten film is deposited and formed on the semiconductor wafer 1 according to the film forming conditions.

Next, the clamp ring 24, which is a feature of the present invention, will be described in detail. 2 is a plan view of the clamp ring 24 according to the present invention seen from the lower surface, FIG. 3 is a sectional view of a contact portion of the clamp ring 24 according to the present invention with a semiconductor wafer, and FIG. Sectional view from the direction,
FIG. 5 is an enlarged view of portion A of FIG. 4, and FIG. 6 is a view showing the flow of purge gas.

As shown in FIGS. 2, 3 and 4, the clamp ring 24 has a ring-shaped ring body 126, and a contact portion 124 is provided on the lower surface of the clamp ring 24 facing the peripheral edge of the semiconductor wafer 1. .

The cross section of the ring body 126 is, for example, trapezoidal and can be configured to have a slope 128.
The outer circumference of the ring body 126 is formed outside the outer circumference of the semiconductor wafer 1, and the inner circumference is formed inside the outer circumference of the semiconductor wafer 1, and covers the peripheral portion of the semiconductor wafer 1.

The contact portion 124 is formed over the entire circumference in a region of width d1 from a position at a distance d2 from the inner peripheral end of the ring body 126 to a position at a distance d3 from the outermost peripheral end of the semiconductor wafer 1.

The distance d2 is, for example, about 1 to 3 mm, and the width d is
1 can be, for example, about 1 mm. Distance d =
When (d1 + d2 + d3) is changed, the semiconductor wafer 1
It is possible to adjust the film thickness distribution at the outer periphery,
An undeposited portion can be formed. The distance d3 may be zero.

The ring body 126 has a contact portion 124.
Other than the above, the semiconductor wafer 1 is kept at the distance Rmax.
It is supposed to face. By changing the distance Rmax, like the distance d, the film thickness distribution in the outer peripheral portion of the semiconductor wafer 1 can be adjusted to form an undeposited portion.

As shown in FIG. 5, the contact portion 124 is a surface having random fine irregularities. This minute uneven surface can be formed by blasting. The distance Rmax to the semiconductor wafer 1 can be formed to be 1.6 μm or less, for example. The distance Rmax can be adjusted by changing the processing conditions such as the grain size of the abrasive grains used for the blasting.

Further, as shown in FIG. 6, the purge gas flowed to prevent the processing gas from wrapping around the semiconductor wafer peripheral portion and the back surface interferes with the contact portion 124 having random fine irregularities as shown by arrow F. It is possible to uniformly flow over the entire circumference of the semiconductor wafer 1 without being damaged.

Thus, the lower surface of the clamp ring 24,
By providing a random minute uneven surface over the entire circumference in a portion facing the outer periphery of the semiconductor wafer 1, a minute gap can be secured between the semiconductor wafer 1 and the semiconductor wafer, and a desired undeposited portion can be formed at the time of film formation. It is possible to prevent film peeling when the clamp ring 24 is removed. Further, it is possible to maintain a uniform temperature distribution without locally depriving the heat of the semiconductor wafer 1 and to ensure a uniform flow of the purge gas, so that a uniform film formation is possible.

FIG. 7 is a view showing another form of the clamp ring according to the present invention. As shown in FIG. 7 (a),
The minute concave and convex portions are formed on the semiconductor wafer 1 of the ring body 226.
It may be formed above the side surface. In this case Rm
ax is the distance from the most cut part of the recess to the surface of the semiconductor wafer 1.

As shown in FIG. 7B, the ring body 32
The inner facing surface 320 and the outer facing surface 322 of the contact portion 324 of FIG. 6 may not be flush with each other, but may have different intervals from the semiconductor wafer 1.

As shown in FIG. 7C, the ring body 42
It is also possible to provide a convex portion 422 having a width d4 formed continuously over the entire circumference on the semiconductor wafer side of No. 6 and provide a contact portion 424 on the surface of the convex portion 422. This width d4
Are formed to have a width d1 or more of the contact portion 424.

According to this structure, by changing the height of the convex portion 422, the semiconductor wafer 1 and the ring body 426 can be changed.
It is also possible to change the distance between and to adjust the undeposited area.

The preferred embodiments of the film forming apparatus according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and naturally, these are also within the technical scope of the present invention. It is understood that it belongs.

For example, the width d1 of the contact surface 124 and the distance Rmax from the semiconductor wafer 1 are not limited to this, and any application can be applied as long as the same effect can be obtained.

[0048]

As described above, according to the present invention,
Since a random minute uneven surface is provided in the contact portion of the clamp ring with the object to be processed, a desired undeposited portion can be formed, peeling of the film can be prevented, and the influence on the object to be processed can be made uniform. Thus, it is possible to provide a film forming apparatus capable of forming a uniform film.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing a film forming processing apparatus using a clamp ring according to the present invention.

FIG. 2 is a plan view of a clamp ring 24 according to the present invention viewed from the semiconductor wafer side.

FIG. 3 is a cross-sectional view of a contact portion of a clamp ring 24 according to the present invention with a semiconductor wafer.

FIG. 4 is a sectional view taken along the direction B in FIG.

5 is an enlarged view of a portion A of FIG.

FIG. 6 is a diagram showing a flow of purge gas.

FIG. 7 is a view showing another form of the clamp ring according to the present invention.

FIG. 8 is a schematic plan view of a conventional clamp ring from the semiconductor wafer side.

FIG. 9 is a sectional view showing a positional relationship between a conventional clamp ring and a semiconductor wafer.

[Explanation of symbols]

1 Semiconductor wafer 24 Clamp ring 124 Contact part 126 ring body 128 slope d1 width d2 distance Rmax distance

Claims (4)

[Claims] 1. A film forming apparatus for performing a film forming process on a processing surface of an object to be processed, comprising a clamp ring for clamping a peripheral portion of the processing surface of the object to be processed, wherein the clamp ring is the object to be processed. A contact portion that makes a full-circumference contact with the object to be processed at the peripheral edge of the contact surface, and a facing portion that faces the processing surface of the object to be processed at an inner peripheral side of the contact portion at a predetermined interval. A film forming apparatus characterized in that a random minute uneven surface is formed. 2. A film forming apparatus for performing a film forming process on a processing surface of an object to be processed, comprising a clamp ring for clamping a peripheral portion of the processing surface of the object to be processed, wherein the clamp ring is the object to be processed. A contact portion that makes a full-circumference contact with the object to be processed at the peripheral edge of the object, and a facing portion that faces the processing surface of the object to be processed at a predetermined interval on the inner peripheral side and the outer peripheral side of the contact part, The film-forming processing apparatus is characterized in that the contact portion is formed with a random minute uneven surface. 3. A film forming apparatus for performing a film forming process on a processing surface of an object to be processed, comprising a clamp ring for clamping a peripheral portion of the processing surface of the object to be processed, wherein the clamp ring is the object to be processed. A continuously formed convex portion having a contact portion that makes a full-circumference with the object to be processed at the peripheral edge portion of
And a facing portion facing the processing surface of the object at a predetermined interval on the inner peripheral side of the contact portion, wherein the contact portion is formed with a random minute uneven surface. , Film forming equipment. 4. The film forming processing apparatus according to claim 1, wherein the random minute uneven surface is formed by blast processing.