JPH08112752A - Method and device for polishing semiconductor wafer - Google Patents

Abstract

PURPOSE: To provide a polishing method of obtaining a semiconductor wafer of high flatness and to provide a polishing device for this polishing method. CONSTITUTION: A polishing cloth 14 is pressed to a surface of a semiconductor wafer 12 to polish the wafer surface while supplying a polishing fluid. During polishing, partly the surface of the wafer is protruded from the polishing cloth, to measure a temperature of the protruded part directly by a thermograph 15. Based on the measured temperature, for instance, a temperature of the polishing fluid is controlled. A temperature of the wafer surface during polishing can be high accurately controlled, and the polishing surface of the semiconductor wafer 12 can be controlled to a high degree of flatness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer polishing method and polishing apparatus, and more particularly to a semiconductor wafer polishing method and polishing apparatus for polishing a silicon wafer that has been subjected to lapping and etching.

[0002]

2. Description of the Related Art A silicon wafer is subjected to a slicing process, a lapping process, an etching process, and a mirror polishing in a polishing process. Up to now, polishing (single-sided polishing) of a silicon wafer has been performed using the apparatus shown in FIG. That is, a plurality of wafers 32 are attached to a plurality of rotary polishing blocks 31 with wax or the like, and a polishing cloth (artificial leather) 33 is adhered to the rotary polishing table (polishing platen) 34.
Press it on top with the appropriate pressure. S for polishing cloth 33
An alkaline colloidal silica polishing liquid containing iO2 as a main component is injected. The polishing with the alkaline colloidal silica is a mechanochemical process by a combined action of mechanical polishing with SiO2 abrasive grains and chemical etching with an alkaline solution.

However, in recent years, the demand for flatness of silicon wafers has become even more severe. And
To increase the flatness, it is necessary to accurately control the temperature of the silicon wafer surface. This is because mechanical polishing produces frictional heat.

[0004]

However, in the conventional polishing method, the temperature of the polishing liquid supplied or the temperature of the polishing platen was merely measured. That is, the surface temperature of the silicon wafer can be measured only indirectly, and the flatness with high accuracy cannot be achieved. That is, in the conventional polished wafer, since the temperature of the polished surface cannot be measured, the temperature control is insufficient,
The flatness was not always satisfactory due to unevenness of the polished surface.

Therefore, as a result of repeated investigations and studies in order to solve the above problems, the inventors have found that the surface temperature of the silicon wafer does not always match the temperature of the polishing platen or the like. Therefore, it was devised to measure the surface temperature directly from the silicon wafer being polished and control the surface temperature based on the measured value. To directly measure the surface temperature of the silicon wafer during polishing, it is easy to measure the partial surface of the silicon wafer protruding from the polishing cloth in a non-contact manner by, for example, a thermograph.

Therefore, an object of the present invention is to provide a polishing method for obtaining a semiconductor wafer having high flatness. Another object of the present invention is to provide a polishing apparatus for obtaining a semiconductor wafer with high flatness.

[0007]

According to a first aspect of the present invention, there is provided a method for polishing a semiconductor wafer in which a polishing cloth is pressed against the surface of the semiconductor wafer to polish the surface of the semiconductor wafer during polishing. This is a method for polishing a semiconductor wafer, in which the temperature of the protruding portion of the semiconductor wafer is measured and the temperature of the semiconductor wafer polished by a polishing cloth is controlled based on the measured temperature.

According to a second aspect of the present invention, the semiconductor wafer temperature is controlled by controlling the temperature of the polishing platen or the temperature of the polishing liquid supplied. Is.

The invention according to claim 3 is a polishing platen,
A polishing cloth held on the polishing platen and pressed against the surface of the semiconductor wafer, a wafer holding member for holding a part of the surface of the semiconductor wafer out of the polishing cloth during polishing, and a polishing liquid on the surface of the semiconductor wafer to be polished. A polishing liquid supply mechanism for supplying, a temperature measuring means for measuring the temperature of the portion of the semiconductor wafer protruding from the polishing cloth, and a temperature control means for controlling the temperature of the semiconductor wafer surface during polishing based on the measured temperature, This is a semiconductor wafer polishing apparatus. The temperature is measured at a portion substantially equal to the temperature of the wafer surface during polishing, that is, a position immediately after the wafer surface comes out of the polishing cloth.

According to a fourth aspect of the present invention, the temperature control means controls the temperature of the surface of the semiconductor wafer being polished by controlling the temperature of the polishing platen or the temperature of the polishing liquid supplied. 3 is a polishing apparatus for a semiconductor wafer.

[0011]

In the method of polishing a semiconductor wafer according to claims 1 and 2, since the temperature of a partial surface of the wafer being polished can be directly measured, it is necessary to accurately know the temperature of the wafer surface being polished. You can Therefore, the temperature of the wafer surface during polishing can be controlled and managed with high accuracy,
A semiconductor wafer having a polished surface with high flatness can be obtained.

In the semiconductor wafer polishing apparatus according to the third and fourth aspects, the surface of the semiconductor wafer is polished by pressing the polishing cloth against the surface of the semiconductor wafer while supplying the polishing liquid. During this polishing, a part of the surface of the semiconductor wafer is projected from the polishing cloth, and the temperature of the projected part is measured. Then, the temperature of the surface of the semiconductor wafer being polished is controlled based on the measured temperature. For example, the temperature of the polishing cloth (polishing platen) is controlled by controlling the temperature of the polishing liquid supplied.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a semiconductor wafer polishing apparatus and a polishing method according to the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of a polishing apparatus according to the present invention.

In these drawings, a chuck (platen) 11 is rotatably supported in a horizontal plane, and a silicon wafer 12 is mounted and held on the chuck 11. The silicon wafer 12 is set by being attached to a chuck 11 made of a ceramics plate by vacuum suction or by sticking it with wax or the like.

A platen 13 is rotatably disposed above the chuck 11. The rotation axis of the surface plate 13 is located eccentric to that of the chuck 11. A polishing cloth 14 made of, for example, artificial leather is attached to the lower surface of the surface plate 13. Then, the polishing cloth 14 is pressed against the surface of the silicon wafer 12 so that the silicon wafer 1
2 The surface will be polished. Furthermore, this polishing cloth 14
A polishing liquid containing, for example, colloidal silica or the like is supplied. The polishing liquid is supplied through the polishing cloth 14 and / or to the exposed portion 17 of the surface of the silicon wafer 12.

A thermograph 15 is arranged diagonally above the chuck 11. Thermograph 15
Is the silicon wafer 1 immediately after protruding from the polishing cloth 14.
The temperature of the surface of the part 18 of No. 2 is measured. The output of the thermograph 15 is input to the control device 16.
The control device 16 is composed of, for example, a computer and controls the temperature of the polishing liquid to be supplied, the rotation speed of the surface plate, the water cooling temperature of the surface plate, etc. based on the temperature measured by the thermograph 15. Instead of the thermograph 15, other temperature measuring means, such as a radiation thermometer, may be used.

The polishing apparatus having the above-mentioned configuration is the control apparatus 1
6, the polishing rate and the like can be controlled in addition to the above. The polishing rate is controlled by changing the polishing load, for example. The pressurizing method is pneumatic pressure.

Then, the following procedure is used to polish a silicon wafer using this polishing apparatus. That is,
Chuck 1 for silicon wafer 12 after etching
1 and held, and a predetermined polishing agent and polishing liquid (PH = 10
Polishing is performed by rotating the chuck 11 at 50 rpm, for example. The rotation speed of the surface plate 13 is 10 to 5
It is possible to choose from any value up to 000 rpm.

In this case, the silicon wafer 12 being polished
Will partially protrude from the polishing cloth 14. The surface temperature of this protruding portion (see FIG. 2) is measured by the thermograph 15.
The controller 16 controls the temperature of the polishing agent and the like in real time based on the measured temperature. As a result,
The temperature of the surface of the silicon wafer 12 is controlled with high accuracy, for example, to a constant temperature. For example, when the measurement temperature is lower than the set temperature, the temperature of the polishing agent is raised. Therefore, the flatness of the surface of the silicon wafer 12 can be maintained at a high level.

[0020]

According to the present invention, the flatness of the surface of a semiconductor wafer can be maintained at a high level.

[Brief description of drawings]

FIG. 1 is a front view of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a polishing apparatus according to an embodiment of the present invention.

FIG. 3 is a front view of a conventional polishing apparatus.

[Explanation of symbols]

 11 Chuck (Wafer Holding Member) 12 Silicon Wafer 13 Surface Plate 14 Polishing Cloth 15 Thermograph (Temperature Measuring Means) 16 Control Device (Temperature Controlling Means) 17 Polishing Liquid Supply Section 18 Temperature Measuring Place

Claims (4)

[Claims] 1. A method of polishing a semiconductor wafer in which a polishing cloth is pressed against the surface of a semiconductor wafer to polish the semiconductor wafer, wherein a part of the surface of the semiconductor wafer is projected from the polishing cloth during polishing, and the temperature of the protruding portion of the semiconductor wafer is increased. And a method for polishing a semiconductor wafer, which controls the temperature of a semiconductor wafer to be polished by a polishing cloth based on the measured temperature. 2. The method for polishing a semiconductor wafer according to claim 1, wherein the temperature of the semiconductor wafer is controlled by controlling a temperature of a polishing platen or a temperature of a polishing liquid supplied. 3. A polishing surface plate, a polishing cloth held on the polishing surface plate and pressed against the surface of the semiconductor wafer, and a wafer holding member for holding a part of the surface of the semiconductor wafer while sticking out of the polishing cloth during polishing. , A polishing liquid supply mechanism that supplies a polishing liquid to the surface of the semiconductor wafer to be polished, a temperature measuring unit that measures the temperature of the portion of the semiconductor wafer that protrudes from the polishing cloth, and a surface of the semiconductor wafer being polished based on the measured temperature. A polishing apparatus for a semiconductor wafer, comprising: a temperature control means for controlling a temperature. 4. The semiconductor wafer according to claim 3, wherein the temperature control means controls the temperature of the surface of the semiconductor wafer being polished by controlling the temperature of the polishing platen or the temperature of the polishing liquid supplied. Polishing equipment.