JPH08281553A - Method and device for mirror finished surface polishing of semiconductor wafer - Google Patents

Abstract

PURPOSE: To provide a mirror finished surface polishing method and a device for easily obtaining a wafer with a superior flat surface. CONSTITUTION: A plurality of adhering disk 2 are secured to a revolving guide disk 3 same as a revolving plate 5 for driving a pressing disk 4, a polishing table 8 is driven to turn by a polishing table-turning shaft 9, the adhering disk 2 rotates, pressed by a pressing disk 4, and the adhering disk 2 revolves through the guide disk 3, while a polishing solution is supplied onto a polishing pad 7, so that the mirror finished surface polishing of the surface of a wafer 1 might be performed. The present device for improving the flat level of the wafer 1 is characterised in that the disk 2 on which the wafer 1 is adhered is formed to have a ring-shape so as to decrease an adhesion area so that the shape of the disk 2 and the inclusions of foreign matters might have littke effect, the polishing pressure is loaded into an inner cavity of the adhering disk 2 through a controlled fluid or a gaseous matter as a medium, and the effect of edge-dulling phenomenon by the viscoelasticity of the polishing pad 7 is reduced by controlling the deformation degree of the protrusion of the wafer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing method and apparatus, and more particularly to a wafer intended to improve the flatness of a wafer for holding a semiconductor wafer such as Si and mirror-polishing the other surface. The present invention relates to a polishing method and device.

[0002]

2. Description of the Related Art In a conventional polishing method, a polishing platen 8 having a polishing pad 7 adhered to its surface is rotated around a rotary drive shaft 6 thereof, and a wafer 1 is adhered to a surface facing the polishing pad 7. An abrasive is supplied while pressing the wafer on the disk 13 against the polishing pad 7 by the pressure disk 4.

[0003]

Conventionally, the wafer 1
The flatness deteriorates under the influence of the shape of the disk 13 to be bonded and the foreign matter 14 being caught in the bonding portion. Further, during polishing, the flatness of the wafer 1 deteriorates under the influence of the edge sagging effect due to the viscoelastic property of the polishing pad 7 (see FIG. 4).

An object of the present invention is to solve the problems of the conventional polishing method and to provide a wafer mirror polishing method and apparatus which can easily obtain a wafer having a good flatness by mirror polishing. .

[0005]

According to the present invention, the disk 2 for bonding wafers is formed in a donut shape to reduce the bonding area,
The influence of the foreign matter 14 being caught in the shape of the disc 2 and the adhesive portion is reduced, and the flatness is improved. Further, a polishing pressure using a controlled fluid or gas as a medium is loaded into the hollow inside of the bonding disk 2 to adjust the amount of convex deformation of the wafer 1, and the influence of the edge sagging effect due to the viscoelastic property of the polishing pad 7. To reduce the flatness of the wafer 1 (see FIG. 3).

[0006]

The disk 2 for adhering the wafer 1 is formed into a donut shape to reduce the adhering area, thereby suppressing the transfer of the shape from the disk 2 to the wafer 1 and reducing the probability of the foreign matter 14 being caught. Further, a polishing pressure is applied to the hollow inside of the adhesive disk 4 using a fluid or gas as a medium to deform the shape of the wafer 1 into a convex shape and adjust the amount of sinking into the polishing pad 7 to reduce the edge sag ( 2-4).

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an apparatus embodying the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a main part of a wafer mirror polishing apparatus according to an embodiment of the present invention. Members common to those shown in FIGS. 2 to 4 are designated by the same reference numerals, and their description will be omitted. Some are omitted.

As shown in FIG. 1, the wafer mirror polishing apparatus includes an adhesive disk 2 for holding a wafer 1 as a material to be polished.
A polishing platen 8 having a polishing pad 7 bonded thereto is disposed on the surface of the bonding disk 2 that faces the side holding the wafer 1. As a pressurizing mechanism for pressurizing the adhesive disc 2 against the polishing platen 8, a pressurizing disc 4 and a pressurizing disc revolution plate 5 for transmitting a pressurizing force and a rotational rotation motion to the pressurizing disc 4 are provided. The adhesive disc 2 is mounted below the pressure disc 4, and a plurality of the adhesion discs 2 having the wafers 1 adhered to each other on the guide disc 3 that revolves in the same manner as the pressure disc revolution disc 5. It is designed to be attached.

The polishing platen 8 is rotationally driven by a polishing platen rotating shaft 9 to which a motor or the like (not shown) is connected, and slides relative to the bonding disc 2. A polishing pad 7, which is a viscoelastic body, is adhered to the upper surface of the polishing platen 8. The polishing platen 8 is rotated while pressing the bonding platen 2 against the polishing platen 8 by the pressure disk 4, and also through the guide disk 3. The surface of the wafer 1 is mirror-polished by supplying the polishing pad 7 with the polishing agent while supplying the polishing disk 7 with an orbital motion by the supply pipe 10.

A wafer 1 is bonded to a doughnut-shaped bonding disk 2 as shown in FIG. 2 and mounted under a pressure disk 4.
For comparison, FIG. 4 shows an example of polishing using the conventional adhesive disk 13. The conventional adhesive disk 13 is affected by the shape of the adhesive disk and the inclusion of the foreign matter 14 ((a) of FIG. 4 shows the start of polishing, (b) shows the end of polishing), and the post-polishing adhesive disk 13
The shape of the wafer 1 separated from the wafer deteriorates ((c) of FIG. 4). On the other hand, in the doughnut-shaped adhesive disc 2 as shown in FIG. 2, a wafer having a good flatness can be obtained without being affected by the adhesive disc shape and the foreign matter 14 being caught (FIG. 2C).

FIG. 3 shows details of the pressure disk 4. The pressure disk 4 is composed of a rubber skirt 4a, a rotation pressure disk 4b, and a pressure disk rotation shaft 4c, and the rotation motion is transmitted from the pressure disk revolution disk 5. Further, the pressurized fluid or pressurized gas 4d is
It is supplied to the inside of the adhesive disk 2 through the holes provided inside the pressure disk revolution disk 5, the pressure disk rotation shaft 4c, and the rotation pressure disk 4b to press the back surface of the wafer 1. As shown in FIG. 1, the pressurized fluid or pressurized gas 4d applies a predetermined polishing pressure to the pressure control valve (11) and the control device (1).
2). As a result, the shape of the wafer 1 is deformed into a convex shape with respect to the polishing pad 7, and the amount of sinking into the polishing pad 7 is adjusted to reduce the edge sag. The rubber skirt 4a seals the pressurized fluid or the pressurized gas 4d so as not to leak to the outside, and at the same time transmits the rotation motion of the pressure disk 4 to the bonding disk 2.
By this rotation movement, the wafer 1 can be formed into a wafer shape without a taper that does not depend on the surface shape of the polishing platen 8 or the polishing pad 7.

[0012]

As described above, in the polishing method and apparatus according to the present invention, the bonding disk for bonding the wafer has a donut shape, and the back surface of the wafer is uniformly coated with the pressurized fluid or the pressurized gas. Since it is rotated and polished while applying various pressures, a flat wafer with no taper can be obtained that is not affected by the shape of the adhesive disk or the inclusion of foreign matter and does not depend on the surface shape of the polishing platen or polishing pad. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a main part of a wafer mirror polishing apparatus according to an embodiment of the present invention.

FIG. 2 shows a state of a donut-shaped adhesive disk having the wafer shown in FIG. 1 bonded thereto during polishing and a wafer shape after peeling.

FIG. 3 shows the detailed structure of the pressure disk shown in FIG. 1 and the arrangement of the bonding disk to which the wafer is bonded.

FIG. 4 shows a state of a normal bonding disk to which a wafer is bonded during polishing and a wafer shape after peeling.

[Explanation of symbols]

 1 wafer 2 donut adhesive disk 3 guide disk 4 pressure disk 4a rubber skirt 4b rotation pressure disk 4c pressure disk rotation axis 4d pressure fluid or pressure gas 5 pressure disk revolution disk 6 polishing disk rotation axis 7 polishing pad 8 Polishing surface plate 9 Polishing surface plate rotating shaft 10 Abrasive supply pipe 11 Pressure adjusting valve 12 Control device 13 Wafer bonding disk 14 Foreign matter

Claims (2)

[Claims] 1. A polishing platen (8) having a polishing pad (7) adhered to its surface is driven to rotate around its rotation axis (9), and a wafer (1) is provided on the surface facing the polishing pad (7). ) Is adhered to the wafer (1) of the bonding disk (2) while pressing the polishing pad (7) with the pressure disk (4) to supply an abrasive, thereby polishing the wafer. A doughnut-shaped adhesive disc (2) is used as a disc for adhering the wafer (1), and polishing pressure is applied to the hollow interior of the adhesive disc using a fluid or gas as a medium to make the pressure distribution on the wafer processing surface substantially uniform. A method for polishing a wafer, characterized in that 2. A polishing platen (8) having a polishing pad (7) adhered to its surface is driven and rotated around its rotation axis (9), and a wafer (1) is provided on the surface facing the polishing pad (7). In the polishing apparatus for polishing the wafer by pressing the wafer (1) of the adhesive disk (2) with the pressure disk (4) pressed against the polishing pad (7) to supply an abrasive. A donut-shaped bonding disk (2) as a disk for bonding the wafer (1), a pressure adjusting valve (11) for applying a polishing pressure using a fluid or gas as a medium in the hollow inside of the bonding disk, and a control device. (12) A wafer polishing apparatus comprising: