JPH07130689A - Grinding device of semiconductor substrate - Google Patents

Abstract

PURPOSE:To secure uniformity within a semiconductor substrate of a grinding amount in a single-leaf type grinding device of semiconductor substrate (wafer). CONSTITUTION:An outer surface 33c (a contact surface of a semiconductor substrate) of a substrate mounting part 33b is outwardly swollen to be a curve surface shape. Further, this is attached to the semiconductor substrate pressed against abrasive cloth and the semiconductor substrate is bent along the outer surface 33c by an elastic force of abrasive cloth. Thus, it is possible to make uniformer a surface inside distribution of conventional process pressure, particularly the surface inside distribution in which elasticity of the abrasive cloth acts largely on a peripheral part of the semiconductor substrate to elevate process pressure of the part. The uniformity inside the surface of a grinding amount is secured more. A curve surface shape is formed, as shown in Fig. 1, by driving a piezo-element, a super-magnetostrictive alloy, etc., 35. Also, it may be fixedly formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor plate (wafer) mounted on a semiconductor substrate mounting portion of a substrate suction plate mounted on a polishing rotary carrier on a polishing platen with a polishing cloth interposed therebetween. The present invention relates to a semiconductor substrate polishing apparatus that faces each other and polishes the surface of a semiconductor substrate with a polishing cloth.

[0002]

2. Description of the Related Art As ULSI becomes highly integrated, there is an increasing demand for reducing a device step difference in a chip when processing a fine pattern. In particular, this is a serious problem in a logic IC that requires a laminated wiring structure. In order to solve this problem, global flattening is being studied.

As a technique capable of achieving global flatness, chemical mechanical polishing (Chemical-M
electrical-Polishing, CMP
The abbreviation method is in the spotlight.

In the CMP method, RIE and PV are used.
Since it is necessary to further widen the process margin such as D and detect the alignment mark of the photolithography more easily, the uniformity of the polishing amount (polishing removal rate) within the surface of the same semiconductor substrate or between the semiconductor substrates is improved. Is an important theme.

Here, the polishing amount in the CMP method is generally Preston's formula; (dT / dt) = k × P
It can be represented by x (ds / dt). Here, T: film thickness, k: proportional constant, P: processing pressure, s: displacement (movement amount) at an arbitrary point in the substrate, and t: time. k is a constant determined by the material to be polished, the polishing agent and the polishing cloth. The distribution of ds / dt in the substrate can be made uniform by making the polishing platen and the rotary carrier for polishing equal in angular velocity. That is, in the single-wafer uniaxial polishing apparatus shown in FIG. 7, the X and Y axes are taken with the center of the polishing disk (circle O1) as the origin, the angular velocity of the polishing disk is .omega.1, and it rotates with the rotary carrier for polishing. Assuming that the angular velocity of the semiconductor substrate (circle O2) is ω2, the velocity u of an arbitrary point P on the semiconductor substrate is u = (R1 + R2) ω1−R2ω2 = (ω1−ω2) R
2 + ω1 R1 Where R1 is a polishing disk (circle O1)
Is a distance vector between the center of the semiconductor substrate (circle O2) and R2 is a distance vector between the center of the semiconductor substrate (circle O2) and the arbitrary point P. Therefore, when ω1 = ω2 u
= Ω1 R1, which is a function of only ω1 and R1 without depending on R2, so that if ω1 and R1 are fixed, u will have a constant vector amount in the substrate. That is, the velocity distribution disappears.

Therefore, in the Preston type, k and (ds / dt) can be made uniform within the substrate. Therefore, in order to make the polishing amount uniform, it is important to make the in-plane distribution of the polishing pressure P uniform. Become.

[0007]

However, since the semiconductor substrate is brought into contact with the polishing cloth attached to the polishing platen, the pressing force of the polishing cloth against the semiconductor substrate is inevitably larger at the peripheral portion of the semiconductor substrate. (See; CMP Seminar Text February 2 1993)
No. 3, 24, pages 71-85: Toshio Doi, sponsored by Realize Co., Ltd.). That is, as shown in FIG. 8A, in normal polishing, since the substrate suction plate is as close to the flat surface as possible, the semiconductor substrate 61 attracted thereto also becomes the flat surface, and this flat plate state Polishing cloth 6 on semiconductor substrate 61
2 comes into contact with each other, and when a predetermined processing pressure W acts, the polishing cloth 6
With the elastic deformation of 2, the pressure P is concentrated around the substrate. Therefore, when polishing is performed in this state, the polishing amount (polishing removal rate) is large in the periphery of the substrate ((b) in the same figure), and finally, the polishing process is completed in the substrate shape state where the pressure distribution becomes more uniform (same as in FIG. Figure (c)).

The problem of the concentration of pressure around the substrate due to the elastic deformation of the polishing cloth is caused by the flatness of the substrate suction plate,
The flatness of the polishing surface plate, the unevenness of the thickness of the polishing cloth, the polishing device such as surface deviation of the polishing surface plate during rotation, the problem of non-uniformity of the processing pressure P associated with the manufacturing accuracy of the polishing cloth, etc. Unlike the problem that can be solved sufficiently by improvement, it is a structural problem that the polishing mechanism originally has, so in order to sufficiently improve the polishing accuracy, it is extremely important to sufficiently eliminate the structural defects. is there.

Therefore, it is an object of the present invention to sufficiently eliminate the above-mentioned structural defects and ensure the uniformity of the pressing force of the polishing cloth against the semiconductor substrate, thereby obtaining the uniformity of the polishing amount. Another object of the present invention is to provide a polishing apparatus for a semiconductor substrate.

[0010]

In order to achieve the above object, the present invention provides a semiconductor substrate mounted on a semiconductor substrate mounting portion of a substrate suction plate mounted on a polishing rotary carrier with a polishing cloth interposed therebetween. Then, in the semiconductor substrate polishing apparatus that faces the polishing platen and polishes the surface of the semiconductor substrate with a polishing cloth, the outer surface of the semiconductor substrate mounting portion of the substrate suction plate has a curved surface shape that bulges outward. .

The curvature of the semiconductor substrate along the outer surface of the semiconductor substrate mounting portion may be made by pressing the semiconductor substrate against the polishing cloth.

A variable width material such as a piezo element or a giant magnetostrictive alloy is interposed between the rotary polishing carrier and the substrate suction plate or in the substrate suction plate, and the semiconductor substrate mounting portion faces the variable width material. Therefore, the variable width material may be driven to change the curved surface shape of the outer surface of the semiconductor substrate mounting portion.

Hard balls may be interposed between the variable width material and the semiconductor substrate mounting portion.

When the variable width material can be driven to change the curved surface shape of the outer surface of the semiconductor substrate mounting portion, the substrate suction plate is located outside the semiconductor substrate mounting portion and outside the semiconductor substrate mounting portion. A notch portion for reducing the rigidity of may be formed in the circumferential direction.

When the variable width material can be driven to change the curved surface shape of the outer surface of the semiconductor substrate mounting portion, the semiconductor substrate mounting portion is formed of stainless steel or phosphor bronze, and the semiconductor substrate mounting portion is formed. The outer surface of the may be Teflon coated.

[0016]

The polishing removal rate can be made uniform from the Preston formula when the polishing pressures are equal. Therefore, if the semiconductor substrate is curved in advance and polishing is performed so that the pressure distribution when the polishing pad is pressed becomes more uniform, a more uniform distribution of the amount of polishing in the substrate surface can be obtained. Then, after the polishing is completed, the curvature of the semiconductor substrate is returned to the original flat plate state, and finally a flat plate-shaped semiconductor substrate having a more uniform polishing amount distribution is obtained. By the way, since the semiconductor substrate is attached to the outer surface of the semiconductor substrate attachment portion of the substrate suction plate, if the outer surface is made a curved surface in advance and the semiconductor substrate is curved along this, the semiconductor substrate can be curved. it can.

After the semiconductor substrate is mounted on the outer surface of the semiconductor substrate mounting portion, when the semiconductor substrate is pressed against the polishing cloth, the polishing cloth has a predetermined thickness and a predetermined elasticity.
The semiconductor substrate is pushed back by the polishing cloth and bends along the outer surface of the semiconductor substrate mounting portion. Therefore, it is possible to bend the semiconductor substrate without providing a means for bending another semiconductor substrate along the outer surface.

The semiconductor curved surface shape in which the pressure distribution becomes uniform in the surface varies depending on the thickness of the polishing cloth, the elastic modulus, the processing pressure, and the like. Therefore, it is desirable that the curved surface shape of the outer surface of the semiconductor substrate mounting portion can be changed. A variable width material such as a piezo element or a giant magnetostrictive alloy is interposed between the polishing rotary carrier and the substrate suction plate or in the substrate suction plate, and this is driven to mount the semiconductor substrate mounting portion facing this. By displacing, the curved surface shape of the outer surface of the semiconductor substrate mounting portion can be arbitrarily changed.

When a hard ball is interposed between the variable width material and the semiconductor substrate mounting portion, the variable width material applies a displacement force to the semiconductor substrate mounting portion not as a surface but as a point.
It is possible to give the outer surface of the semiconductor substrate mounting portion a smooth curved surface shape with less distortion.

When the semiconductor substrate mounting portion is curved by the variable width material, a notch portion for reducing the rigidity of the semiconductor substrate mounting portion is formed at a position outside the semiconductor substrate mounting portion of the substrate suction plate, so that the semiconductor substrate mounting portion is formed. It is possible to obtain sufficient curvature near the ends.

When the semiconductor substrate mounting portion is curved with the variable width material, the semiconductor substrate mounting portion is made of stainless steel or phosphor bronze to prevent plastic deformation and to sufficiently withstand shear stress. Therefore, it becomes possible to maintain a desired curved surface and repeatedly make the curved surface. In addition, since the outer surface is coated with Teflon, metal impurities are prevented from entering the semiconductor substrate.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, a first embodiment of the present invention will be described. The present embodiment is an example of a single-wafer uniaxial polishing device,
In FIG. 2, a polishing rotary carrier 2 is attached to a carrier support shaft 1. In this embodiment, the carrier support shaft 1 is configured to rotate at an angular velocity equal to that of a polishing platen described later.

A substrate suction plate 3 is attached to the polishing rotary carrier 2. The substrate suction plate 3 is provided with a substrate fixing guide 3a on the outer peripheral portion. The inside of the substrate fixing guide 3a becomes the semiconductor substrate mounting portion 3b. The substrate fixing guide 3a prevents the semiconductor substrate from slipping out of the semiconductor substrate mounting portion 3b during polishing. The outer surface 3c of the semiconductor substrate mounting portion 3b is a mounting surface of the semiconductor substrate, and has a curved surface shape that bulges outward. A suction hole (not shown) is provided in the semiconductor substrate mounting portion 3b. For example, eight suction holes are provided coaxially with the semiconductor substrate mounting portion 3b on the circumference of a predetermined diameter (for example, a diameter of ⅔ of the diameter of the semiconductor substrate) at a position relatively close to the substrate fixing guide 3a. (See Figure 5). A vacuum pump (not shown) is connected to the rear of the suction hole, and by driving it, the outside air is sucked through the suction hole. Due to this suction force, the semiconductor substrate is sucked onto the outer surface 3c and handled and transported. The curved surface shape 3c of the outer surface is combined with the suction force of the suction holes when the semiconductor substrate is pressed against the polishing cloth as described later, and the shape of the semiconductor substrate is a predetermined curved surface with a more uniform pressing force. The shape is determined to be the shape. In addition, the curved surface shape 3c is the thickness of the semiconductor substrate, the thickness of the polishing cloth,
Multiple types depending on polishing conditions such as elastic modulus and processing pressure
Be prepared. The semiconductor substrate mounting portion 3b is integrated with the substrate suction plate 3 and is made of a material that is not chemically attacked and has a small deformation with respect to a load, such as ceramic or glass. Plastic may be used as long as it has excellent pressure resistance and durability.

Next, the polishing platen (not shown) is formed in a disk shape and is made of a material such as stainless steel and ceramics that is not chemically attacked.

Next, a polishing cloth (not shown) has a constant polishing ability, a constant frictional resistance, an appropriate elastic modulus (hardness), a thickness, and a material excellent in chemical resistance. Materials such as urethane foam, non-woven fabric and artificial leather are used and attached to the polishing surface plate.

This embodiment is constructed in this way, and the semiconductor substrate is sucked onto the outer surface 3c of the substrate suction plate 3 at a predetermined position. In this state, since the suction holes are located relatively close to the substrate fixing guide 3a, the semiconductor substrate is curved along the outer surface 3c with a certain curvature. Then, this is conveyed, pressed against the polishing cloth attached to the polishing platen at a predetermined processing pressure, the valve of the vacuum pump is closed, and the vacuum pump is stopped. Then, the semiconductor substrate is pushed back from the polishing cloth, so that the semiconductor substrate is curved along the outer surface 3c. Note that the end portion of the semiconductor substrate is subject to both the force pushed back from the polishing cloth and the force to return it due to the elastic force of the semiconductor substrate itself.
Does not have to adhere to. The vacuum pump valve is closed to maintain the vacuum state of the suction holes, and therefore the semiconductor substrate bending force is also generated by suction from the suction holes. The curved surface shape is formed by both the suction force from the holes. In this way, the semiconductor substrate is curved, and the pressure distribution in the substrate surface becomes more uniform. Therefore, if polishing is performed in this state, Preston's equation; (dT / dt) = k × P ×
By (ds / dt), a more uniform distribution of the polishing amount in the substrate surface can be obtained.

When the semiconductor substrate has a curved surface shape, the polishing removal rate is set to the central portion (Center) and the peripheral portion (E) of the substrate.
The experiment compared with dge) will be described with reference to FIGS. A 5-inch substrate was used, and the outer surface of the semiconductor substrate mounting portion was formed into an arc shape so that the central portion was convex with respect to the peripheral portion, and the displacement amount was given to the central portion and the peripheral portion.
The polishing conditions were such that the processing pressure was 493 g / cm @ 2, H-1 (manufactured by Rodel Nitta) was used as the polishing cloth, the polishing platen rotation speed was 30 rpm, and the polishing rotation carrier rotation speed was 30 r.
pm. Then, the semiconductor was curved and polished in the same manner as in the first embodiment. According to FIG. 3, when the semiconductor substrate is not curved (position on the horizontal axis 0), the polishing removal rate in the peripheral portion of the semiconductor substrate is considerably higher than that in the central portion. When a displacement of about 18 μm is applied between the center and the peripheral portion of the outer surface, the difference in polishing removal rate becomes small, and when a displacement of about 30 μm is applied between the center and the peripheral portion of the outer surface, the polishing is performed. When the difference in removal rate is further reduced and a displacement of about 50 μm is applied between the central portion and the peripheral portion of the outer surface, the removal rate at the central portion of the semiconductor substrate is higher than that at the peripheral portion. ing. From these, the relationship shown by the straight line in FIG. 3 is obtained, and when the displacement of about 34 μm is applied between the central portion and the peripheral portion of the outer surface, the polishing removal rate between the central portion and the peripheral portion of the semiconductor substrate is almost the same. Expected to match. FIG. 4 is a graph showing the difference between these removal rates as a ratio. The vertical axis is represented by a numerical value of [(maximum removal rate-minimum removal rate) / (2 × average removal rate)].

Next, a second embodiment of the present invention will be described. Figure 5
In, the inside of the contact between the polishing rotary carrier 12 mounted on the carrier support shaft 11 and the substrate suction plate 13 mounted on the carrier support shaft 11 extends axially over both of them and in the radial direction. A space portion 14 extending to the position of the substrate fixing guide 13a is formed, the semiconductor substrate mounting portion 13b is formed to have a predetermined thickness so as to be bendable, and the outer surface 13c is formed on a variable width material 15 described later. It is formed on a flat surface without driving. Then, in the central portion, the polishing rotary carrier 12 and the substrate suction plate 13 are extended portions 12d, 1 having a predetermined cross-sectional area which are close to each other.
A gap portion 16 having a width 3d and having a width substantially equal to the width of the variable width material 15 is provided between the tip surfaces of the extending portions 12d and 13d.

Since it is preferable that the semiconductor substrate mounting portion 13b maintains the curved shape and that the same curved surface shape is reproduced by the same driving of the variable width material 15, it has sufficient elasticity and easily undergoes plastic deformation. It is desirable that the material is not. Further, since the curved semiconductor substrate mounting portion 13b is supported at the position of the variable width material 15 and receives a processing pressure, and this processing pressure is transmitted to the semiconductor substrate mounting portion 13b, the semiconductor substrate mounting portion 13b is sufficiently resistant to shear stress. It is desired that the material be obtained. Further, since the semiconductor device manufacturing process is extremely reluctant to mix metal impurities in order to ensure the reliability of the semiconductor element, when the semiconductor substrate mounting portion 13b contains a metal component, it abuts on the semiconductor substrate. It is preferable to form a shielding film for metal impurities on the portion. Therefore,
Particularly, it is preferable that the semiconductor substrate mounting portion 13b is made of stainless steel or phosphor bronze, and the outer surface 13c is coated with Teflon. Here, Teflon means polytetrafluoroethylene. The semiconductor substrate mounting portion 13b may be made of plastic as long as it has a high pressure resistance and is made of an elastic material. The semiconductor substrate mounting portion 13b
May be integrally formed with the substrate suction plate 13 main body, or may be separately manufactured and fixed to the substrate suction plate 13 main body (not shown). Next, the suction holes 18 are coaxial with the semiconductor substrate mounting portion 13b, and the substrate fixing guide 13 is provided.
Eight pieces are provided on the circumference of a predetermined diameter (for example, a diameter of 2/3 of the diameter of the semiconductor substrate) at a position relatively close to a. The suction hole 18 is connected to a tube (not shown) in the space 14,
Further, it is connected to a vacuum pump (not shown), and by driving it, the outside air is sucked through the suction holes. Due to this suction force, the semiconductor substrate is sucked onto the outer surface 13c and handled and transported. Similar to the first embodiment, the curved surface shape 13c of the outer surface is formed so that the shape of the semiconductor substrate becomes a predetermined curved surface shape in which the pressing force is more uniform due to the suction force and the pushing back force from the polishing cloth. Is determined.

The variable width material 15 is attached to the gap portion 16. The variable width material 15 is a material whose width can be changed by applying a control force such as an electric force or a magnetic force.
For example, a piezo element, a giant magnetostrictive alloy or the like is used. When the variable width material 15 is driven by the control force, the width of the variable width material 15 increases, and the width of the variable width material 15 comes into contact with the tip surfaces of the extending portions 12d and 13d to try to spread the distance between the extending portions 12d and 13d. Board mounting portion 13b, that is, its outer surface 13c
Has a curved surface shape.

Next, the relationship between the polishing conditions such as the type of polishing cloth, the processing pressure, the thickness and type of the semiconductor substrate, and the width of the variable width material that gives the pressure distribution required at that time is created as table data. I'll do it.

With such a structure, before the semiconductor substrate is adsorbed on the outer surface, after adsorbing it or after pressing it against the polishing cloth, the type of polishing cloth, the processing pressure, the thickness of the semiconductor substrate, etc.
Depending on the polishing conditions such as type, based on the table data,
The set width of the variable width material is determined, and the control force is applied to achieve this width. Then, in a state in which the semiconductor substrate is pressed against the polishing cloth, a predetermined curved surface shape is formed on the semiconductor substrate by the suction force and the pushing back force from the polishing cloth as in the first embodiment, and polishing is performed in this state. To do. As a result, a desired semiconductor substrate having a uniform polishing amount distribution can be obtained. Next, when the polishing conditions are changed, the width of the variable width material 15 is changed according to the table data, and the polishing is performed by this.

Since the semiconductor substrate mounting portion 13b is made of stainless steel or phosphor bronze, a predetermined curved surface shape is maintained and repeatability is ensured. Further, since the outer surface 13c is coated with Teflon, metal impurities are greatly prevented from being mixed into the semiconductor substrate adsorbed by the outer surface 13c when the present polishing apparatus is used.

In this embodiment, the number and positions of the variable width materials can be set so that the curved surface shape of the outer surface is optimum. For example, in FIG. 6, one width-adjustable material 25 is provided at the center of the semiconductor substrate mounting portion 23b, and eight width-variable materials 25 are circumferentially equidistantly provided at a position approximately in the middle between the center and the end of the semiconductor mounting portion 23b. Is. Then, by setting the set width of the eight variable width materials 25 arranged at a position approximately in the middle between the center and the end portion to be smaller than the set width of the width variable material 25 at the center portion, It is possible to obtain an optimum curved surface shape of the outer surface 23c having a sufficiently preferable curvature even in the vicinity of a position approximately in the middle of.

Next, a third embodiment of the present invention will be described. Figure 1
In the substrate suction plate 33, the space portion 3 that extends radially to the extension of the inner end surface 33d of the substrate fixing guide 33a and axially extends to the vicinity of the outer surface 33c.
4 are formed. Then, in the space portion 34, one is provided at the center and six are provided at equal intervals circumferentially at positions that are approximately three equal to the distance between the center and the end of the semiconductor substrate mounting portion 33b. Eight variable width materials 35 are fixedly arranged on the rotary polishing carrier 32. And each width variable material 35
A hard ball 37 is arranged between the center of the tip surface of the and the semiconductor substrate mounting portion 33b. The hard balls 37 may be fixed to the variable width material 35, may be fixed to the semiconductor substrate mounting portion 33b, or may be fixed to both of them.
A hard ball 37 is arranged in each hole of one cage (not shown) arranged in the space 34 to hold the hard ball 37 without being fixed to both the variable width material 35 and the semiconductor substrate mounting portion 33b. May be. A hard material is used for the hard ball 37, and for example, a metal ball such as steel is used.

Next, a cutout portion 33f is formed outside the substrate fixing guide 33a up to a position on the extension of the outer end surface 33e of the substrate fixing guide 33a and over the entire circumference, and has a predetermined thickness. The thick semiconductor substrate mounting portion 33b is extended to the outside of the substrate fixing guide 33a while maintaining its thickness.

Since the other structure is similar to that of the second embodiment,
The description is omitted.

The present embodiment is constructed in this way, and when the variable width material 35 is driven, each variable width material expands in width according to its control force, and the outer surface 33c of the semiconductor substrate mounting portion 33b is predetermined. To the curved surface shape. Since the variable width material 35 is arranged not only on the central portion but also on each circumference of the substrate mounting portion 33b, which is divided into about three equal parts, the outer surface 33c having a sufficiently preferable curvature also in these portions. Is obtained. Further, the flat end surface of the variable width material 35 is directly attached to the board mounting portion 33.
In the case of contacting with b, the board mounting portion 33b becomes the flat surface at the flat end surface of the variable width material 35, and the outer surface 33c
There is a possibility that a sharp change in the curve occurs from the curved surface of the flat surface to the flat surface, and thus the pressure distribution may be distorted, resulting in uneven polishing. However, in this embodiment, the width of the variable width material 35 is increased by the steel. Since it is transmitted to the substrate mounting portion 33b by point contact via the sphere 37, the above problem does not occur and a pressure distribution without distortion can be obtained. Further, if the rigidity of the portion of the board suction plate 33 outside the board mounting portion 33b is high when the board mounting portion 33b is curved, the board mounting portion 33b can be sufficiently curved at the end ring-shaped portion of the board mounting portion 33b. No, that is, the ring-shaped portion serves as a flat surface and the pressure distribution in this portion becomes large, but since the notch 33f is provided, the notch 33f is squeezed, so that the substrate fixing guide 33a is used as a fulcrum for the substrate. Even the end ring-shaped portion of the attachment portion 33b is sufficiently rotated, and this portion can be sufficiently curved. It should be noted that when the pressure is high in the ring-shaped portion, the supply amount of the polishing agent toward the center of the substrate decreases, which causes a decrease in the polishing removal rate in the center of the substrate. It becomes possible to sufficiently supply the abrasive to the central portion.

In the above embodiment, the semiconductor substrate is bent by both the suction force from the suction holes and the pushing back force from the polishing cloth. However, the semiconductor substrate is bent only by the pushing back force from the polishing cloth. Good.

The present invention can also be used when polishing is performed by changing the polishing pressure of the semiconductor substrate at each in-plane portion. That is, for example, when a film having a predetermined thickness is formed on the surface of the semiconductor substrate and the film thickness is non-uniform, the outer surface of the semiconductor substrate mounting portion is provided with a predetermined thickness in accordance with the non-uniformity. When the semiconductor substrate is curved into a shape, and the semiconductor substrate is brought into contact with the curved surface to bend the semiconductor substrate, it is possible to increase and decrease the pressing force with the polishing cloth at a thick film thickness and a thin film thickness, respectively. When this is done, the thick film portion can be polished more and the thin film portion can be polished less, so that the remaining film thickness can be made more equal. As described above, the present invention can be used for highly precise control of the in-plane polishing pressure of the semiconductor substrate.

[0041]

Since the present invention is configured as described above, it is possible to control the polishing pressure distribution with higher accuracy, and therefore it is possible to control the polishing amount with high accuracy in the polishing process of a semiconductor substrate. become.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part of a third embodiment of the present invention, in which FIG. 1 (a) is a sectional view and FIG. 1 (b) is a bottom view.

2A and 2B are explanatory views of the main part of the first embodiment of the present invention, in which FIG. 2A is a sectional view and FIG. 2B is a bottom view.

FIG. 3 is a graph showing a difference in polishing removal rate between a central portion of a semiconductor substrate and a peripheral portion of the semiconductor substrate when a curvature rate of the semiconductor substrate is changed in the first embodiment of the present invention.

FIG. 4 is a graph showing the degree of uniformity of polishing removal rate when the ratio of curvature of the semiconductor substrate is changed in the graph of FIG. 3;

5A and 5B are explanatory views of the main part of the second embodiment of the present invention, in which FIG. 5A is a sectional view and FIG. 5B is a bottom view.

6 (a) and 6 (b) are a sectional view and a bottom view, respectively, of the main part of another embodiment of the second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a relative relationship between rotation of a polishing platen and rotation of a polishing rotation carrier.

FIG. 8 is an explanatory diagram showing changes in the processed cross-sectional shape and the pressure distribution in the substrate during conventional polishing.

[Explanation of symbols]

 2, 12, 32 Rotating carrier for polishing 3, 13, 33 Substrate suction plate 3b, 13b, 23b, 33b Semiconductor substrate mounting portion 3c, 13c, 23c, 33c Outer surface 15, 25, 35 Width variable material 37 Hard ball 33f Notch Department

Claims (6)

[Claims] 1. A semiconductor substrate mounted on a semiconductor substrate mounting portion of a substrate suction plate mounted on a rotary polishing carrier is opposed to a polishing platen with a polishing cloth interposed therebetween, and the surface of the semiconductor substrate is fixed. A semiconductor substrate polishing apparatus for polishing with a polishing cloth, wherein the outer surface of the semiconductor substrate mounting portion of the substrate suction plate has a curved surface shape that bulges outward. 2. The polishing of the semiconductor substrate according to claim 1, wherein the curve of the semiconductor substrate along the outer surface of the semiconductor substrate mounting portion is made by pressing the semiconductor substrate against the polishing cloth. apparatus. 3. The variable width material such as a piezo element or a giant magnetostrictive alloy is interposed between the rotary carrier for polishing and the substrate suction plate or in the substrate suction plate according to claim 1 or 2. The semiconductor substrate mounting portion faces the variable width material, and the curved surface shape of the outer surface of the semiconductor substrate mounting portion can be changed by driving the variable width material. Polishing equipment for semiconductor substrates. 4. The semiconductor substrate polishing apparatus according to claim 3, wherein hard balls are interposed between the variable width material and the semiconductor substrate mounting portion. 5. The substrate suction plate according to claim 3 or 4, wherein a notch portion for reducing rigidity at an outer position of the semiconductor substrate mounting portion is provided at a position outside the semiconductor substrate mounting portion. An apparatus for polishing a semiconductor substrate, which is formed in a direction. 6. The semiconductor substrate mounting portion according to any one of claims 3 to 5, wherein the semiconductor substrate mounting portion is formed of stainless steel or phosphor bronze, and the outer surface of the semiconductor substrate mounting portion is coated with Teflon. A semiconductor substrate polishing apparatus characterized in that