JPH01153273A - Grinding method for semiconductor wafer - Google Patents

Abstract

PURPOSE:To improve the grinding and rinsing operationability of a semiconductor wafer and prevent the grinding unevenness and scratches by supplying grinding liquid and pure water for rinsing from either upper or lower direction of both faces of the wafer. CONSTITUTION:A semiconductor wafer 4 is held at both sides by upper and lower surface plates 1 and 2 with grinding tools 5 and 6. In this state, liquid is supplied from the supply ports 7 and 12 provided to the upper and lower surface plates 1 and 2 to the upper and lower faces of the semiconductor 4 relatively moving both faces of the wafer 4 and the grinding tools 5 and 6, and both faces of the wafer 4 are ground uniformly without scratches. In the next step, pure water is uniformly and quickly supplied from the supply ports 7 and 12 provided to the upper and lower surface plates 1 and 2 by switching selector valves 14 and 15 after the finish of grinding for rinsing both faces of the wafer 4 and suppressing oxidation to the utmost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of polishing a semiconductor wafer, and particularly to a method of simultaneously polishing both sides of a semiconductor wafer.

[Prior Art] FIG. 2 shows a conventional example of an apparatus for polishing both sides of a semiconductor wafer.

In FIG. 2, 1 is an upper surface plate, 2 is a lower surface plate, 3 is a 1-wafer support plate, and 4 is a semiconductor wafer placed on the wafer support plate 3. The wafer support plate 3 is located between the upper surface plate 1 and the lower surface plate 2, and is set to rotate relative to these surface plates 1.degree.2.

Polishing cloths 5 and 6 are bonded to the upper surface plate 1 and the undefined portion 5IlI2.

The upper surface plate 1 is provided with polishing liquid supply lowers, and each supply lower is connected to a polishing liquid receiving tray 9 via a tube 8.

10 is a polishing liquid supply pipe, and 11 is a pure water supply pipe.

When performing double-sided polishing of a semiconductor wafer using an apparatus equipped with such elements, first, a polishing liquid is discharged from the polishing liquid supply pipe 10. This polishing liquid is once received by the polishing liquid receiving tray 9 and then supplied from the upper chamber 11 side to the installation location of the semiconductor wafer 4 via the tube 8 and the supply lower. On the other hand, when the polishing liquid is supplied, the polishing cloths 5 and 6 attached to the surface plate 1.degree.2 sandwich the wafer 4 and simultaneously polish both surfaces of the wafer. When this work process is completed, the supply of polishing liquid is stopped and pure water is supplied to the pure water supply pipe 1 instead.
1. Flow from the upper surface plate 1 side through the tube 8 and the supply lower to perform rinsing with pure water and finish polishing.

[Problems to be Solved by the Invention] This type of polishing is important for mirror finishing of semiconductor wafer products. By the way, in the conventional technology as described above, since the polishing liquid is supplied from the upper surface plate side, it is difficult to uniformly supply the polishing liquid to both sides of the wafer, which tends to cause uneven polishing, scratches, etc. It is necessary to quickly rinse the wafer with pure water to prevent oxidation of the wafer, but since pure water is only supplied from the upper surface plate side, it is not possible to quickly supply pure water to both sides of the wafer, and the semiconductor wafer is There were some points that should be improved, such as some oxidation.

The present invention has been made in view of the above points, and its purpose is to improve the quality of polishing and pure water rinsing operations, and to effectively prevent the occurrence of polishing unevenness, scratches, oxidation, etc. An object of the present invention is to provide a wafer polishing method that can improve the quality of wafers.

[Means for Solving the Problems] The above object is to sandwich both sides of a semiconductor wafer between upper and lower surface plates equipped with polishing tools, supply a polishing liquid to a location where the semiconductor wafer is placed, and In the wafer polishing method, the polishing is performed by relatively moving the polishing tool and the semiconductor wafer, and then pure water is supplied to rinse both sides of the semiconductor wafer. The polishing liquid and the rinsing pure water are supplied to both sides of the semiconductor wafer from both sides of the semiconductor wafer from above and below through these supply ports to perform wafer polishing and rinsing operations. This is achieved by

[Function] According to the present invention having such a configuration, a polishing liquid can be supplied during the wafer polishing process, and pure water can be supplied from both sides of the semiconductor wafer from above and below during the rinsing process. Therefore, during the wafer polishing process, the polishing liquid is uniformly supplied to both surfaces of the wafer, effectively preventing the occurrence of polishing unevenness, scratches, etc.

Also, during the rinsing process, pure water can be uniformly and quickly supplied to both surfaces of the wafer, thereby suppressing oxidation of the wafer as much as possible.

[Example] An embodiment of the present invention will be described based on FIG.

FIG. 1 shows an example of an apparatus embodying the wafer polishing method of the present invention. In the figure, the same reference numerals as those in the conventional example shown in FIG. 2 previously described indicate the same or common elements. .

That is, 1 is the upper surface plate, 2 is the lower surface plate, 3 is the wafer support, and 4
is a semiconductor wafer.

The wafer support 3 supports a plurality of semiconductor wafers 4.

Although only one wafer support 3 in this embodiment is shown in the drawing, other similar wafer supports 3 are arranged at appropriate intervals in the circumferential direction of the surface plates 1 and 2. or,
Each wafer support 3 rotates via a planetary gear of a planetary gear mechanism (not shown), and the upper and lower surface plates 1 and 2 are rotated by a sun gear. The surface plate 1.2 rotates relative to each other.

In the upper chamber II, a polishing liquid and pure water supply lower is arranged,
Each supply lower is connected to a polishing liquid receiver 9 via a tube 8, and furthermore, in this embodiment, the lower surface plate 2 is also provided with a supply port 12 for polishing liquid and pure water, and is connected to the polishing liquid via a passage 13. Liquid and pure water are distributed to each supply port 12. 1
4.15 is a switching valve that switches the supply of polishing liquid or pure water to either one.

When polishing both sides of a semiconductor wafer using an apparatus equipped with such elements, it is performed as follows. First, when performing polishing work, a polishing liquid is supplied from each supply lower of the upper surface plate 1 (this polishing liquid supply has already been described in the [Prior Art] section, so the explanation will be omitted). The polishing liquid is also supplied from the lower surface plate 2 side through the passage 13 and the supply port 12.

With the polishing liquid supplied to both sides of the wafer 4 in this manner, the polishing cloths 5 and 6 sandwich the wafer 4, and the polishing cloths 5 and 6 are rotated relative to each other on both sides of the wafer 4 to perform polishing. . When this work process is finished, the supply of the polishing liquid is stopped and the polishing liquid is instead passed through the supply lowers 12 provided on the upper and lower surface plates 1 and 2 to the wafer 4.
Pure water is supplied to both sides from both the top and bottom to perform a pure water rinse, and polishing is completed through a series of these steps.

In the polishing work of this example, stainless steel surface plates with a diameter of 630 mm were used as the upper and lower surface plates 1 and 2, and the semiconductor wafer 4 was a GaAS wafer with a thickness of 500 μm.
jJn doped, semi-insulating (1,O,O
) surface as-wrapped wafer was used. Further, there are 18 polishing liquid supply lowers each having a diameter of 6 mm on the upper surface plate side, and the same applies to the polishing liquid supply ports 12 on the lower surface plate side.

During the polishing process, the semiconductor wafer 4 is subjected to a surface pressure of 80 Q/cm, and the lower surface plate 2 is rotated at a speed of 15 Q/cm.
ROM, the upper surface plate 1 is given a rotation speed of 5 rpm via a deceleration mechanism, and a hypochlorous acid-based etching solution is used as the polishing liquid, and 100 to 150 cc are applied from the upper and lower surface plates 1 and 2, respectively.
Polishing was performed by supplying a polishing liquid of /min.

When polishing and rinsing with pure water were performed under these conditions, the GaAS wafers had the following properties compared to conventional ones:
It was possible to obtain a high quality semiconductor wafer with a very good mirror finish with almost no scratches, oxidation, etc.

[Effects of the Invention] As described above, according to the present invention, by supplying the polishing liquid and pure water from both above and below the semiconductor wafer,
The quality of polishing and pure water rinsing work can be improved,
As a result, it is possible to effectively prevent the occurrence of polishing unevenness, scratches, oxidation, etc., and improve the quality of semiconductor wafers.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an example of an apparatus embodying the wafer polishing method of the present invention, and FIG. 2 is a partial sectional view showing a conventional wafer polishing apparatus. 1: Upper surface plate, 2: Lower surface plate, 3: Wafer support, 4: Semiconductor wafer, 5.6: Polishing tool (polishing cloth), 7.12: Supply port for polishing liquid and pure water. Tomi 1 Old ■ Upper surface plate 4: Semiconductor wafer

Claims (1)

[Claims] (1) Both sides of the semiconductor wafer are held between upper and lower surface plates equipped with a polishing tool, a polishing liquid is supplied to the location where the semiconductor wafer is placed, and both sides of the semiconductor wafer and the polishing tool are moved relative to each other. In the wafer polishing method, in which polishing is performed by polishing the semiconductor wafer, and then deionized water is supplied to rinse both sides of the semiconductor wafer, supply ports for the polishing liquid and deionized water for rinsing are arranged on both the upper and lower surface plates, and A method for polishing a semiconductor wafer, characterized in that the polishing liquid and the deionized water for rinsing are supplied to both sides of the semiconductor wafer from either the upper or lower direction through a supply port to perform a wafer polishing operation and a rinsing operation.