JPH02301135A - Method for polishing wafer chamfer - Google Patents

Abstract

PURPOSE:To lengthen the life of a polishing material and shorten processing time without damaging the principal plane of a wafer. CONSTITUTION:To polish a chamfer 1a of a wafer 1, a polisher 6 comprising a rotating shaft 3 coupled to a driving source, a planar rotating body 4 fixed at the tip of the rotating shaft 3 and a polishing cloth 5 attached to the principal plane of this rotating body 4 with adhesive or the like is used. That is, with the polishing cloth 5 of the polisher 6 brought in contact with the chamfer 1a of the wafer 1 with the same angle as the tilt angle theta of the plane to be chamfered of the chamfer 1a, the wafer 1 is rotated counterclockwise while the rotating body 4 is rotated clockwise and the rotating body 4 is revolved counterclockwise as regards the wafer 1 to polish the chamfer 1a of the wafer 1. Then the wafer is placed upside down and fixed on a wafer chuck and the other chamfer 1b of the wafer 1 is polished as well as said chamfer 1a.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an improvement in a method for polishing a chamfered portion of a wafer.

[Prior Art and Problems] As is well known, large diameter wafers are used to make chips that serve as base materials for semiconductor devices, but when such wafers are transported, their chamfered portions (periphery) This can cause chips and cracks to occur. For this reason, the peripheral edge of the wafer is beveled (chamfered) and, if desired, mirror polished.

As a mirror polishing method for the chamfered portion of the wafer, there is a method of pressing the wafer at the angle of the chamfer against a cylindrical polishing cloth, or a method of pressing a rotating brush against the entire surface of the wafer.
There is a method that takes advantage of the fact that the contact friction resistance at the chamfered portion at this time is greater than that at the main surface of the wafer.

However, these techniques have various problems such as (1) long processing time, (2) poor durability of the polishing cloth, and (2) risk of damaging the main surface of the wafer on which elements are to be formed.

The present invention has been made in view of the above circumstances, and by polishing the wafer by bringing the abrasive into contact with the chamfered surface in parallel to the chamfered surface of the chamfered portion of the wafer, the main surface of the wafer is not damaged, and the abrasive is An object of the present invention is to provide a method for polishing the periphery of a wafer, which can extend the life of the wafer and shorten the processing time.

[Means for Solving the Problems J] The present invention provides a method for polishing a chamfered portion of a wafer using a planar rotating body having an abrasive material attached to its main surface. The chamfered portion of the wafer is formed by rotating the wafer or rotating the rotating body relative to the wafer while contacting the wafer at an angle of inclination of the inclined surface of the wave chamfered portion or at an angle approximating it. The purpose is to polish the

In the present invention, a polishing cloth used for polishing wafers can be used as the material for the polishing stone attached to the planar rotating body.

In addition, in the present invention, when polishing the chamfered part of the wafer, it is necessary to either rotate only the wafer without bringing the flat rotating body into contact with the chamfered part of the wafer, or ■ rotate the flat rotating body against the wafer. Polishing is performed by rotating the wafer or by rotating the planar rotating body relative to the wafer. Note that during polishing, it is preferable to make the rotating body revolve and rotate on its own axis, since the entire polishing cloth contributes to the polishing.

[Function] According to the present invention, by polishing the wafer by bringing the abrasive into contact with the chamfer plate of the chamfered portion of the wafer in parallel, the main surface of the wafer is not damaged and the life of the abrasive is extended. In addition, since the wafer can be rotated at high speed, processing time can be reduced compared to conventional methods.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is an explanatory diagram of a polishing method for a wafer chamfering portion according to the present invention, and FIG. 2 is an explanatory diagram showing a partially enlarged main part of FIG. 1.

1 in the figure is a wafer supported by a wafer chuck 2. When polishing the chamfered portion 1a of the wafer 1, a rotating shaft 3 connected to a drive source (not shown) and a
a planar rotating body 4 fixed to the tip of the rotating body 4;
A stone grinder 6 consisting of an abrasive cloth 5 attached to the main surface of the machine with an adhesive or the like is used.

That is, in this embodiment, first, the polishing cloth 5 of the polishing machine 6 is brought into contact with the chamfered portion 1a of the Uni-Noh 1 at the same angle as the inclination angle (θ) of the chamfered surface of the chamfered portion 1a. , the unino 11 is rotated in the direction of arrow A (counterclockwise), the rotating body 4 is rotated in the direction of arrow B (clockwise), and the rotating body 5 is rotated in the direction of arrow C (
By rotating the wafer 1 (counterclockwise), the chamfered portion 1a of the wafer 1 is polished. Next, the sea urchin/\ is turned over and fixed to the wafer chuck 2, and the other chamfered part 1b of the sea urchin 11 is ground in the same way as the one chamfered part 1a.

As described above, according to the present invention, the polishing cloth 5 of the polishing machine 6 is adjusted to the inclination angle (θ) of the chamfered surface of the chamfered portion 1a (or lb) with respect to the chamfered portion 1a (or lb) of the sea urchin/X1.
Since the polishing process is performed while the wafer is in contact with the wafer at the same angle, the chamfered portion 1a of the wafer 1 can be
, lb polishing can be performed, and the life of the polishing cloth 5 can be extended.

Furthermore, since there is no fear that the main surface of the wafer will be 1 m (M), the wafer 1 can be rotated at high speed, thereby reducing the processing time compared to the conventional method.

In fact, when comparing the case using the method of the present invention (former) and the case using a fixed abrasive wheel (latter), in the latter case, when using a fixed abrasive wheel consisting of #800 and #2000 abrasive grains, respectively. Maximum surface roughness approximately 2μm (
Average surface ↑■ width approx. 1.4 μm), 0.7 μm (
The average surface roughness was approximately 0.2 μm), whereas in the latter case, it was confirmed that the average surface roughness was 0.01 μm.

From this, it is clear that the present invention is superior to the conventional method in terms of polishing accuracy.

In the above embodiment, a case has been described in which the chamfered portion of the wafer is polished while the wafer and the rotating body rotate and the rotating body revolves around the wafer, but the present invention is not limited to this. For example, if only one of the wafer or the rotating body is to be rotated, or if both the rotating body and the wafer are to be rotated, a dedicated means may be used.

Further, in the above embodiment, a case is described in which the polishing cloth is made to be the same as the inclination angle (θ) of the chamfered surface of the chamfered portion of the wafer, but the present invention is not limited to this. Even in this case, the same effects as in the above embodiment can be expected.

[Effects of the Invention] As detailed above, according to the present invention, polishing is performed by bringing the abrasive into contact with the chamfered surface of the chamfered portion of the wafer in parallel, thereby preventing damage to the main surface of the wafer, and
It is possible to provide a method for polishing a chamfered portion of a wafer, which can extend the life of the abrasive material and can shorten the machining time compared to the conventional method because the wafer can be rotated at high speed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a polishing method for a chamfered portion of a wafer according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a main part of FIG. 1 in a partially enlarged manner. DESCRIPTION OF SYMBOLS 1... Wafer, 2... Wafer chuck, 4... Flat rotating body, 5... Polishing cloth (abrasive material). Applicant's agent Patent attorney Takehiko Suzue Figure 2

Claims (1)

[Claims] In a method of polishing a chamfered portion of a wafer using a planar rotating body with an abrasive attached to its main surface, the abrasive of the rotating body is applied to the chamfered portion of the wafer at an angle of inclination of the inclined surface of the chamfered portion or an approximation thereof. polishing a chamfered portion of a wafer, the chamfered portion of the wafer being polished by at least one of rotating the wafer or revolving the rotating body with respect to the wafer while contacting the wafer at a certain angle; Method.