JP2002264005A - Polishing method for semiconductor wafer and polishing device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing method for a semiconductor wafer capable of improving shape accuracy of a polishing face. SOLUTION: When pressing the semiconductor wafer W onto a polishing cloth on a polishing surface plate through an elastic body by air to execute one-side polishing, the semiconductor wafer W is pressed by air supplied to a circular recessed part 4 open downward having a diameter larger than the wafer W through an elastic sheet 6 stretched in an opening end part of the recessed part 4 to airtightly close the recessed part 4, a support position P of the elastic sheet 6 in the opening end part of the recessed part 4 is adjusted vertically to the upper face of the semiconductor wafer W, and the one-side polishing is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polishing a semiconductor wafer and a polishing apparatus therefor, and more particularly to a semiconductor wafer which is polished on one side by pressing a semiconductor wafer against a polishing cloth on a polishing platen via an elastic body with air. And a polishing apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, as a semiconductor wafer polishing method and a polishing apparatus of this kind, as shown in FIG. 9, a flat circle having air enclosed therein is used as a wafer holder attached to a polishing head (not shown). A rubber chuck 31 which has a plate shape and presses the semiconductor wafer W, and a retainer ring 32 which is vertically movably fitted to the outer periphery of the rubber chuck 31 to reduce the concentration of pressure on the outer peripheral portion of the polishing head.
A single semiconductor wafer W is held on a polishing head via a rubber chuck 31, and the semiconductor wafer W is rotated while pressing the semiconductor wafer W against a polishing cloth 33 stuck on a polishing platen (not shown). A single-side polishing method is known.

[0003]

However, in the conventional method and apparatus for polishing a semiconductor wafer, when a semiconductor wafer is polished using this method and apparatus, depending on polishing conditions, the outer circumference of the polished surface of the semiconductor wafer may be reduced. The part may have a sharp shape, or it may have a drooped shape,
There is a problem that the shape accuracy is reduced. As described above, the shape accuracy of the outer peripheral portion of the polished surface of the semiconductor wafer is reduced.
It is considered that the pressure distribution is applied to the outer peripheral portion of the semiconductor wafer by the pressing of the air through the elastic body during the polishing of the semiconductor wafer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for polishing a semiconductor wafer and a polishing apparatus therefor, which can improve the precision of the shape of a polished surface.

[0005]

According to a first aspect of the present invention, there is provided a method for polishing a semiconductor wafer, comprising the steps of: pressing a semiconductor wafer against a polishing cloth on a polishing platen with an air through an elastic body; Upon polishing, the semiconductor wafer is pressed by air supplied to the recess through an elastic sheet that is stretched at the opening end of the circular recess that opens downward with a larger diameter than the wafer and that hermetically closes the recess, The method is characterized in that the support position of the elastic sheet at the opening end of the concave portion is vertically adjusted with respect to the upper surface of the semiconductor wafer to perform one-side polishing. The elastic sheet has a Young's modulus of 1 to 1000.
It is preferable to have a uniform thickness of MPa.

A second method for polishing a semiconductor wafer is as follows.
When the semiconductor wafer is pressed against the polishing cloth on the polishing platen with air through an elastic body and polished on one side, the semiconductor wafer is stretched at the opening end of a circular concave portion which opens downward with a larger diameter than the wafer. The method is characterized in that the recess is pressed by air supplied to the recess through an elastic sheet that hermetically closes the recess, and the rigidity of the recess in the vicinity of the inner peripheral surface of the elastic sheet is increased to perform one-side polishing. It is preferable that the means for increasing the rigidity increase the thickness of the concave portion near the inner peripheral surface of the elastic sheet. Further, the means for increasing the rigidity may be to attach an elastic sheet having a large Young's modulus to a portion near the inner peripheral surface of the elastic sheet in the concave portion.

On the other hand, the first semiconductor wafer polishing apparatus is a device for single-side polishing by pressing a semiconductor wafer against a polishing cloth on a polishing platen through an elastic body with air, and is mounted below a polishing head. A disc-shaped holder body provided with a circular recess having a diameter larger than the semiconductor wafer and opening downward, and a first elastic member which is stretched at an opening end of the recess in the holder body and hermetically closes the recess. A seat and first air supply / discharge means for supplying / discharging air to / from a recess closed by the first elastic sheet.

[0008] The second semiconductor wafer polishing apparatus is a single-side polishing apparatus which presses a semiconductor wafer against a polishing cloth on a polishing platen through an elastic body with air and has a larger diameter than the semiconductor wafer and is opened downward. A disc-shaped holder main body provided with a circular concave portion to be provided; a first elastic sheet stretched over an opening end of the concave portion in the holder main body to airtightly close the concave portion;
A first air supply / discharge means for supplying / discharging air into / from a concave portion closed by the first elastic sheet; a dish-shaped polishing head provided with a circular concave portion having a larger diameter and opening downward from the holder main body; A second elastic sheet which is stretched over an opening end of the concave portion of the head, hermetically closes the concave portion of the polishing head, and supports the upper end of the holder body concentrically with the polishing head;
A second air supply / discharge means for supplying / discharging air into / from the concave portion of the polishing head closed by the elastic sheet.

[0009] The third semiconductor wafer polishing apparatus comprises a second semiconductor wafer polishing apparatus.
An auxiliary polishing head, which is provided with a circular concave portion having a diameter larger than that of the polishing head and opening downward, and provided integrally with the polishing head so as to be concentric with the polishing head, A retainer ring stretched between the opening end of the recess and the opening end of the polishing head for hermetically closing the recess of the auxiliary polishing head and slidingly contacting the polishing cloth on the polishing platen is concentric with the polishing head. Third to support
An elastic sheet and third air supply / discharge means for supplying / discharging air to / from the concave portion of the auxiliary polishing head closed by the third elastic sheet are provided.

[0010] The fourth semiconductor wafer polishing apparatus comprises a second semiconductor wafer polishing apparatus.
Alternatively, the polishing apparatus according to the third aspect, further includes a sensor for measuring a distance between a bottom surface of the concave portion of the polishing head and an upper surface of the holder main body.

A fifth semiconductor wafer polishing apparatus comprises:
The fourth aspect is characterized in that the polishing head is provided with a reference sensor for measuring an interval between a bottom surface of the concave portion and a predetermined portion of an inner peripheral surface of the concave portion.

[0012]

In the first method for polishing a semiconductor wafer,
The pressure distribution at the outer peripheral portion of the semiconductor wafer, which is applied by the pressing of the air through the elastic sheet, is controlled. When the Young's modulus of the elastic sheet is less than 1 MPa, the elastic sheet easily wraps around the wafer end. On the other hand, 100
If it exceeds 0 MPa, the back surface shape of the wafer tends to be adversely affected. More preferred Young's modulus of the elastic sheet,
It is 2.5 to 250 MPa. As the elastic sheet, a rubber or other elastic sheet is used.

Further, in the second method for polishing a semiconductor wafer, similarly to the first method, the pressure distribution in the outer peripheral portion of the semiconductor wafer applied by the pressing of air through the elastic sheet is controlled.

On the other hand, in the first semiconductor wafer polishing apparatus, by moving the polishing head up and down, the support position of the first elastic sheet at the opening end of the concave portion of the holder main body is set on the polishing platen. The position can be adjusted vertically with respect to the upper surface of the semiconductor wafer placed on the cloth.

In the second apparatus for polishing a semiconductor wafer, in addition to the action of the first apparatus, the pressure in the concave portion of the holder body and the pressure in the concave portion of the polishing head are maintained at a constant level. The supporting position of the first elastic sheet with respect to the upper surface is kept constant.

In the third semiconductor wafer polishing apparatus, in addition to the action of the second apparatus, when the holding of the semiconductor wafer by the holder consisting of the holder body and the first elastic sheet is released during polishing, Sliding of the semiconductor wafer on the polishing cloth is prevented. Also, the sagging of the outermost peripheral portion of the wafer can be prevented by the effect of pushing the polishing cloth by the retainer ring.

In the fourth semiconductor wafer polishing apparatus, the distance between the bottom surface of the concave portion of the polishing head and the upper surface of the holder main body can be measured in addition to the operation of the second or third device. As the sensor, either a contact type or a non-contact type may be used.

In the fifth semiconductor wafer polishing apparatus, in addition to the function of the fourth device, noise cancellation such as vibration can be performed, and a reference for measurement by the fourth sensor can be obtained.

When the Young's modulus of the first elastic sheet is less than 1 MPa, the elastic sheet easily wraps around the wafer end. On the other hand, if it exceeds 1000 MPa, the back surface shape of the wafer tends to be adversely affected. The more preferable Young's modulus of the elastic sheet is 2.5 to 250 MPa. As the first to third elastic sheets, sheets made of rubber or another elastic body are used.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a sectional view showing a first embodiment of a semiconductor wafer polishing apparatus according to the present invention, and an enlarged sectional view of a main part. In the figure, reference numeral 1 denotes a polishing platen having a polishing cloth 2 adhered to the upper surface thereof, and the polishing platen 1 is rotated via a rotation driving device (not shown). Reference numeral 3 denotes a holder (chuck) which is mounted below the polishing head and presses and holds the semiconductor wafer W against the polishing cloth 2 as described later. The holder 3 has a diameter larger than the outer diameter of the semiconductor wafer W as appropriate. And a disc-shaped holder body 5 provided with a circular recess 4 that opens downward, and a first elastic sheet that is stretched over the opening end of the recess 4 in the holder body 5 and hermetically closes the recess 4. 6 is comprised. The concave portion 4 of the holder main body 5 in the holder 3 is provided to be appropriately shallower than the thickness of the semiconductor wafer W, and the first elastic sheet 6 has a Young's modulus of 1 to 1.
It is made of a rubber sheet having a uniform thickness of 000 MPa (average: 0.1 to 1.0 mm). The recess 4 of the holder 3 closed by the first elastic sheet 6 supplies first air supply / discharge means (not shown) for supplying air to the inside of the recess 4 or discharging air from the inside of the recess 4. It is connected through a ventilation hole 7 opening on the bottom surface of the recess 4 and a first ventilation pipe 8.

Reference numeral 9 denotes a polishing head provided with a circular concave portion 10 which is appropriately larger in diameter than the outer diameter of the holder main body 5 of the holder 3 and is opened downward. This polishing head 9 is polished by a rotary driving device (not shown). It is rotated in the same direction as the surface plate 1, is raised and lowered by a lifting drive device (not shown) such as a servomotor, and is provided so as to be horizontally movable on a wafer mounting table (not shown). A second elastic sheet 11 that closes the recess 10 hermetically and supports the upper end of the holder main body 5 in the holder 3 concentrically with the polishing head 9 is stretched over the open end of the recess 10 in the polishing head 9. Like the first elastic sheet 6, the second elastic sheet 11 is a rubber sheet having a Young's modulus of 1 to 1000 MPa and a uniform thickness (0.1 to 1.0 mm in average).
The inside of the concave portion 10 of the polishing head 9 closed by the second elastic sheet 11 is provided with second air supply / discharge means (not shown) for supplying air to the concave portion 10 or discharging air from the concave portion 10. Are connected via a ventilation hole 12 and a second ventilation conduit 13 which are opened on the bottom surface of the concave portion 10. On the other hand, on the bottom surface of the concave portion 10 of the polishing head 9, the concave portion 10
A contact type or non-contact type sensor 14 for measuring the distance between the bottom surface of the holder 3 and the upper surface of the holder main body 5 in the holder 3 is additionally provided. On the other hand, on the bottom surface of the concave portion 10 of the polishing head 9 separated from the sensor 14, a contact type or a non-contact type for measuring the interval between the bottom surface of the concave portion 10 and a predetermined portion 15 protruding from the inner peripheral surface of the concave portion 10 Reference sensor 16 is provided.

Reference numeral 17 denotes a dish-shaped auxiliary polishing head provided with a circular concave portion 18 having a diameter larger than the outer diameter of the polishing head 9 and opening downward. The auxiliary polishing head 17 is concentric with the polishing head 9. They are provided integrally in a shape. The auxiliary polishing head 1 is provided between the opening end of the concave portion 18 and the opening end of the polishing head 9 in the auxiliary polishing head 17.
7, a third elastic sheet 20 that stretches the airtightly closed concave portion 18 and supports a retainer ring 19 slidably in contact with the polishing cloth 2 on the polishing platen 1 concentrically with the polishing head 9. Like the first and second elastic sheets 6 and 11, the third elastic sheet 20 is a rubber sheet having a Young's modulus of 1 to 1000 MPa and a uniform thickness (0.1 to 1.0 mm in average). The inside of the concave portion 18 of the auxiliary polishing head 17 closed by the third elastic sheet 20 supplies the air into the concave portion 18 or discharges the air from the concave portion 18.
It is connected to an air supply / discharge means (not shown) via a ventilation hole 21 opened on the bottom surface of the recess 18 and a third ventilation pipe 22.

In order to perform single-side polishing of a semiconductor wafer in a single wafer using the semiconductor wafer polishing apparatus having the above structure, first, the polishing head 9 is horizontally moved together with the auxiliary polishing head 17 and the holder 3 onto a wafer mounting table. After the first elastic sheet 6 of the holder 3 is brought into contact with the semiconductor wafer W by being lowered by the operation of the elevation drive device, the air in the recess 4 of the holder main body 5 is discharged by the operation of the first air supply / discharge means. I do. By discharging the air, the first elastic sheet 6 is attracted to the bottom surface of the concave portion 4 and the semiconductor wafer W is also attracted to the first elastic sheet 6 by the suction cup.

Next, the polishing head 9 is moved to the auxiliary polishing head 17.
After the semiconductor wafer W is lifted together with the holder 3 to which the semiconductor wafer W has been sucked, the wafer is horizontally moved onto the polishing cloth 2 of the polishing platen 1, and then lowered by the operation of the lifting / lowering drive device to bring the semiconductor wafer W into contact with the polishing cloth 2. The contact of the semiconductor wafer W with the polishing pad 2 changes the measured value of the sensor 14 (displaces in a certain direction).
When the displacement is detected, the operation of the lifting drive device is stopped.

Next, the support position P of the first elastic sheet 6 at the bottom surface of the concave portion 4 of the holder main body 5 and at the open end of the concave portion 4.
Since the gap L between the first air supply and the discharge is known in advance, the vacuum by the first air supply / discharge means is released, and the polishing head 9 is raised by the above-mentioned gap L by the operation of the lifting / lowering drive device. In this state, the support position P of the first elastic sheet 6 matches the height of the upper surface of the semiconductor wafer W on the polishing pad 2.
Next, air is supplied into the recess 4 of the holder body 5 of the holder 3 by the operation of the first air supply / discharge unit to a required pressure, and the polishing head 9 is operated by the operation of the second air supply / discharge unit. Air is supplied into the recess 10 to hold the holder body 5.
And the polishing head 9 is moved up and down by the operation of the elevating drive device, and the supporting position P of the first elastic sheet 6 is adjusted.
Is adjusted in the vertical direction so as to be at a required height position with respect to the upper surface of the semiconductor wafer W. Thereafter, the recess 18 of the auxiliary polishing head 17 is operated by the operation of the third air supply / discharge means.
Air is supplied to the inside so that the lower surface of the retainer ring 19 is always in sliding contact with the polishing pad 2.

Then, the polishing platen 1 and the polishing head 9 are rotated in the same direction by the operation of the respective rotary driving devices, and the semiconductor wafer W is polished single-sided in a single wafer system. Since the thickness of the semiconductor wafer W decreases with the progress of the single-side polishing of the semiconductor wafer W, the polishing drive 9 is moved down by operating the lifting / lowering drive device so that the value measured by the sensor 14 is always constant. At this time, if the pressure in the concave portion 4 of the holder main body 5 and the pressure in the concave portion 10 of the polishing head 9 in the holder 3 are kept constant, the support position P of the semiconductor wafer W moves downward of the upper surface of the semiconductor wafer W. Since it follows, there is no need to correct the position adjusted as described above.

Here, the concave portion 4 of the holder has an inner diameter of 200.7.
mm, the first elastic sheet has a Young's modulus of 2.5 MPa, and a thickness of 0.
With a 6mm rubber sheet, the air pressure in the recess is 200gf /
Using the above-mentioned polishing apparatus having a size of cm ² , a silicon wafer having a diameter of 200 mm and a thickness of 0.73 mm was placed on the upper surface of the first elastic sheet with respect to the supporting position of the first elastic sheet. 0 from the top of
When the single-side polishing was performed by changing the position to be 08 mm higher, the position C: 0.46 mm higher from the upper surface of the silicon wafer, and the position D: 0.82 mm higher than the upper surface of the silicon wafer, the pressure distribution applied to the silicon wafer was 3 and the cross-sectional shape of the polished surface after polishing is as shown in FIG. As can be seen from FIG. 3, the pressure distribution varies depending on the position where the first elastic sheet is supported at the outer peripheral portion where the distance from the center of the silicon wafer is 80 mm or more. Further, as can be seen from FIG. 4, the cross-sectional shape of the outer peripheral portion of the silicon wafer greatly changes depending on the position where the first elastic sheet is supported. Therefore, when the above-mentioned silicon wafer is polished on one side by the above-mentioned polishing apparatus, the support position of the first elastic sheet with respect to the upper surface of the silicon wafer is set to 0.01 to 0.08 mm from the upper surface of the silicon wafer.
It can be seen that, when the position is higher, the distribution of pressure applied to the outer peripheral portion of the silicon wafer is well controlled, and the shape accuracy of the polished surface can be improved.

On the other hand, the concave portion of the holder has an inner diameter of 200.7 mm,
The first elastic sheet is a rubber sheet whose Young's modulus is 2.5 MPa, its supporting position is 0.1 mm higher than the upper surface of the silicon wafer, and the air pressure in the recess is 200 gf / cm ² , and the above-mentioned polishing apparatus is used. 200mm, 0.73mm thickness
The thickness of the first elastic sheet is set to a:
When single-side polishing was performed in a single-wafer method while changing the thickness to 0.1 mm, b: 0.6 mm, and C: 1.0 mm, the pressure distribution applied to the silicon wafer was as shown in FIG. On the other hand, the concave portion of the holder has an inner diameter of 200.7 mm, and the first elastic sheet has a thickness of 0.6.
mm, the supporting position is 0.0 mm from the top surface of the silicon wafer.
With a rubber sheet 1mm higher, the air pressure in the recess
Using the above-mentioned polishing apparatus having a diameter of 20 gf / cm ² and a diameter of 20 gf / cm ²
A silicon wafer having a thickness of 0 mm and a thickness of 0.73 mm was prepared by setting the Young's modulus of the first elastic sheet to A: 2.5 MPa and B: 25 MPa.
The pressure distribution applied to the silicon wafer was as shown in FIG. 6 when the single-side polishing was performed by a single wafer method instead of a and 250 MPa. It can be seen from FIG. 5 that the larger the thickness of the first elastic sheet, the smaller the change in the pressure distribution.
FIG. 6 shows that when the Young's modulus of the first elastic sheet is about 25 MPa, the amount of change in the pressure distribution is small.

FIG. 7 is an enlarged sectional view of a main part showing a second embodiment of the semiconductor wafer polishing apparatus according to the present invention. The polishing apparatus is provided at the opening end of the recess 4 in the holder main body 5, and reduces the thickness of the portion of the first elastic sheet 23 near the inner peripheral surface of the recess 4 in the first elastic sheet 23 which hermetically closes the recess 4. The thickness is increased as approaching the surface, and the rigidity of the portion is increased. By doing so, the distribution of the pressure applied to the outer peripheral portion of the semiconductor wafer is well controlled, and the shape accuracy of the polished surface can be improved. The other configurations, functions and effects are almost the same as those of the first embodiment. Therefore, the components having the same functions are denoted by the same reference numerals, and the description thereof will be omitted.

FIG. 8 is an enlarged sectional view of a main part showing a third embodiment of the semiconductor wafer polishing apparatus according to the present invention. In this polishing apparatus, a first elastic sheet 24, which is stretched at the opening end of the recess 4 in the holder body 5 and hermetically closes the recess 4, is stretched over the opening end of the recess 4 with a uniform thickness. The main sheet 24a is attached to the main sheet 24 and a portion of the main sheet 24 near the inner peripheral surface of the concave portion 4.
The first elastic sheet 24 has a greater rigidity in the vicinity of the inner peripheral surface of the recess 4 in the first elastic sheet 24. By doing so, similarly to the second embodiment, the distribution of the pressure applied to the outer peripheral portion of the semiconductor wafer is well controlled, and the shape accuracy of the polished surface can be improved. The other configurations, functions and effects are almost the same as those of the first embodiment. Therefore, the components having the same functions are denoted by the same reference numerals, and the description thereof will be omitted.

In each of the above-described embodiments, the auxiliary polishing in which the holder 3 is supported on the polishing head 9 via the second elastic sheet 11 and the retainer ring 19 is supported via the third elastic sheet 20. The case where the head 17 is provided integrally with the polishing head 9 has been described. However, the present invention is not limited to this. The auxiliary polishing head 17 that integrally provides the holder 3 with the polishing head 9 and supports the retainer ring 19 is used. It may not be provided, or it may be configured such that the holder 3 is supported by the polishing head 9 via the second elastic sheet 11 and the auxiliary polishing head that supports the retainer ring 19 is not provided.

[0032]

As described above, according to the first and second methods for polishing a semiconductor wafer of the present invention, the pressure distribution on the outer peripheral portion of the semiconductor wafer, which is applied by pressing the air through the elastic sheet, is controlled. Therefore, the shape accuracy of the polished surface can be improved.

On the other hand, according to the first semiconductor wafer polishing apparatus, the supporting position of the first elastic sheet at the opening end of the concave portion of the holder main body is moved by moving the polishing head up and down. Since the position can be adjusted vertically with respect to the upper surface of the semiconductor wafer placed on the polishing cloth, the pressure distribution in the outer peripheral portion of the semiconductor wafer can be controlled.

According to the second apparatus for polishing a semiconductor wafer, in addition to the function and effect of the first apparatus, the pressure in the concave portion of the holder body and the pressure in the concave portion of the polishing head are maintained at a constant level. Since the supporting position of the first elastic sheet with respect to the upper surface of the wafer is kept constant,
It is not necessary to correct the support position of the first elastic sheet according to the progress of the polishing of the semiconductor wafer.

According to the third apparatus for polishing a semiconductor wafer, the holding of the semiconductor wafer by the holder consisting of the holder main body and the first elastic sheet is released during the polishing, in addition to the effect of the second apparatus. In this case, since the semiconductor wafer is prevented from sliding on the polishing pad, the semiconductor wafer can be prevented from being damaged. Also, the sagging of the outermost peripheral portion of the wafer can be prevented by the effect of pushing the polishing cloth by the retainer ring.

According to the fourth semiconductor wafer polishing apparatus, it is possible to measure the distance between the bottom surface of the concave portion of the polishing head and the upper surface of the holder main body, in addition to the effects of the second or third device. Therefore, accurate positioning of the support position of the first elastic sheet can be performed.

According to the fifth semiconductor wafer polishing apparatus, in addition to the function and effect of the fourth device, noise such as vibration can be canceled, and the measurement standard of the fourth device can be obtained. More accurate positioning of the support position of the first elastic sheet can be performed.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a semiconductor wafer polishing apparatus according to the present invention.
It is sectional drawing which shows embodiment.

FIG. 2 is an enlarged sectional view of a main part of the polishing apparatus of FIG.

FIG. 3 is an explanatory diagram showing a relationship between a supporting position of a first elastic sheet and a distribution of a pressure applied to a semiconductor wafer in the polishing apparatus of FIG. 1;

FIG. 4 is an explanatory view showing a relationship between a support position of a first elastic sheet in the polishing apparatus of FIG. 1 and a cross-sectional shape of a polished surface of a semiconductor wafer after polishing.

FIG. 5 is an explanatory diagram showing a relationship between a thickness of a first elastic sheet and a distribution of pressure applied to a semiconductor wafer in the polishing apparatus of FIG.

FIG. 6 is an explanatory diagram showing a relationship between a Young's modulus of a first elastic sheet and a distribution of a pressure applied to a semiconductor wafer in the polishing apparatus of FIG. 1;

FIG. 7 shows a second embodiment of the semiconductor wafer polishing apparatus according to the present invention.
It is an expanded sectional view of the principal part showing an embodiment.

FIG. 8 shows a third embodiment of the semiconductor wafer polishing apparatus according to the present invention.
It is an expanded sectional view of the principal part showing an embodiment.

FIG. 9 is a schematic sectional view of a conventional semiconductor wafer polishing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 polishing platen 2 polishing cloth 4 concave portion 5 holder main body 6 first elastic sheet 9 polishing head 10 concave portion 11 second elastic sheet 14 sensor 16 reference sensor 17 auxiliary polishing head 18 concave portion 19 retainer ring 20 third elastic sheet 23 first Elastic sheet 24 First elastic sheet 24a Main sheet 24b Sub-sheet W Semiconductor wafer P Support position

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiromichi Isogai 6-861-5, Higashiko, Seirocho, Kitakanbara-gun, Niigata Prefecture (72) Inventor Masatoshi Ikeda 6-861-Higashiko, Seirocho, Kitakanbara-gun, Niigata 5 Niigata Toshiba Ceramics Co., Ltd. (72) Inventor Takayuki Masunaga 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa F-term in Toshiba Production Technology Center Co., Ltd. 3C058 AA07 AB04 AC02 BA07 DA17

Claims (13)

[Claims] 1. An open end of a circular concave portion which is opened downward by a diameter larger than that of a semiconductor wafer when the semiconductor wafer is pressed against a polishing cloth on a polishing platen by an air through an elastic body and polished on one side. Pressed by air supplied to the recess through an elastic sheet that is stretched to close the recess airtightly, and adjusts the support position of the elastic sheet at the opening end of the recess in the vertical direction with respect to the upper surface of the semiconductor wafer. A method for polishing a semiconductor wafer, comprising performing single-side polishing. 2. The elastic sheet according to claim 1, wherein said elastic sheet has a Young's modulus of 1 to 1000.
2. The method for polishing a semiconductor wafer according to claim 1, wherein the substrate has a uniform thickness of MPa. 3. An open end portion of a circular concave portion which is larger in diameter than the wafer and is opened downward when the semiconductor wafer is pressed against the polishing cloth on a polishing platen by an air via an elastic body and is single-side polished. A semiconductor which is pressed by air supplied to the concave portion via an elastic sheet which is stretched over the airtightly and seals the concave portion, and which is polished on one side by increasing the rigidity of a portion near the inner peripheral surface of the elastic sheet in the concave portion. Wafer polishing method. 4. The method of polishing a semiconductor wafer according to claim 3, wherein said means for increasing the rigidity increases the thickness of the concave portion near the inner peripheral surface of the elastic sheet. 5. The method for polishing a semiconductor wafer according to claim 3, wherein the means for increasing the rigidity is to attach an elastic sheet having a large Young's modulus to a portion of the recess near the inner peripheral surface of the elastic sheet. 6. An apparatus for single-side polishing by pressing a semiconductor wafer against air on a polishing plate on a polishing table via an elastic body, mounted on a lower portion of a polishing head, and having a diameter larger than that of the semiconductor wafer and opening downward. A disc-shaped holder body provided with a circular recess to be formed, a first elastic sheet stretched over an opening end of the recess in the holder body to airtightly close the recess,
The first for supplying and discharging air into the recess closed by the elastic sheet
An apparatus for polishing a semiconductor wafer, comprising: an air supply / discharge unit. 7. An apparatus for polishing a semiconductor wafer on one side by pressing the semiconductor wafer with air via an elastic body on a polishing platen on a polishing platen, wherein a circular concave portion having a diameter larger than that of the semiconductor wafer and opening downward is provided. A disc-shaped holder main body, a first elastic sheet stretched over an opening end of the recess in the holder main body to airtightly close the recess, and supply and exhaust air into the recess closed by the first elastic sheet. A first air supply / discharge means, a dish-shaped polishing head provided with a circular concave portion having a larger diameter and opening downward from the holder main body, and a polishing head which is stretched at an opening end of the concave portion of the polishing head. A second method for hermetically closing the recess and supporting the upper end of the holder body concentrically with the polishing head.
A polishing apparatus for a semiconductor wafer, comprising: an elastic sheet; and second air supply / discharge means for supplying / discharging air to / from a concave portion of the polishing head closed by the second elastic sheet. 8. An auxiliary polishing head having a dish shape provided with a circular concave portion having a diameter larger than that of the polishing head and opening downward, and provided integrally with the polishing head so as to be concentric with the polishing head. The retainer ring, which is stretched between the opening end of the concave portion and the opening end of the polishing head, hermetically closes the concave portion of the auxiliary polishing head and slidably contacts the polishing cloth on the polishing platen with the polishing head. 3rd concentric support
8. The semiconductor wafer polishing apparatus according to claim 7, further comprising: an elastic sheet; and third air supply / discharge means for supplying / discharging air into / from a recess of the auxiliary polishing head closed by the third elastic sheet. 9. The semiconductor wafer polishing apparatus according to claim 7, further comprising a sensor for measuring a distance between a bottom surface of the concave portion of the polishing head and an upper surface of the holder main body. 10. The semiconductor wafer polishing apparatus according to claim 9, further comprising a reference sensor for measuring an interval between a bottom surface of the concave portion and a predetermined portion of an inner peripheral surface of the concave portion in the polishing head. 11. The first elastic sheet has a Young's modulus of 1 to 1.
11. The semiconductor wafer polishing apparatus according to claim 6, wherein the apparatus has a uniform thickness of 000 MPa. 12. The apparatus for polishing a semiconductor wafer according to claim 6, wherein the first elastic sheet is formed by increasing the thickness of a portion near the inner peripheral surface of the concave portion of the holder main body. 13. The first elastic sheet wherein an elastic sheet having a large Young's modulus is attached to a portion near the inner peripheral surface of the concave portion of the holder main body.
An apparatus for polishing a semiconductor wafer as described in the above.