JPH0671559A - Lapping method - Google Patents

Abstract

PURPOSE:To enable it to perform good lapping without lowering the extent of yield rate by preventing any crack or chip from occurring in a workpiece in a lapping process even in such a case that there are warpage and waviness in the workpiece. CONSTITUTION:A coating layer 10 is formed on the surface of a workpiece 6 and, after both the main surfaces are shaped almost parallelly and flatly with each other, a shaped workpiece A is set to a carrier 3, and both these upper and lower plates 1, 2 and the carrier 3 are relatively moved to some extent in a state that these upper and lower plates 1, 2 are made to contact with both these main surfaces, thus lapping takes place.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for lapping a piezoelectric substrate, a semiconductor substrate or the like, and more specifically, it suppresses local stress from being applied to a workpiece such as a piezoelectric substrate or a semiconductor substrate during lapping. , For efficient wrapping.

[0002]

2. Description of the Related Art Lapping of an object to be processed such as a piezoelectric substrate or a semiconductor substrate is usually performed by using a lapping device as shown in FIG. In this lapping apparatus, a mounting hole 3a for mounting the workpiece 6 is formed between the upper plate 1 and the lower plate 2 as shown in FIG. 6, and a gear 3b (shown in FIG. 5) is provided on the outer periphery. 7 is a lapping device in which a plurality of carriers 3 each having a sun gear (sun gear) 4 and an internal gear (internal gear) 5 formed therein are formed. As shown, the mounting hole 3 of the carrier 3
After the workpiece 6 such as a piezoelectric substrate or a semiconductor substrate is mounted on a, the upper and lower plates 1 and 2 are brought into contact with both sides of the workpiece 6, and a lapping agent (abrasive stone grain) is contained from the outside. The carrier 3 is rotated and revolved by rotating the sun gear 4 (FIG. 5) while supplying the lapping liquid (not shown), and the upper and lower plates 1 and 2 and the carrier 3 are relatively moved, Lapping of the workpiece 6 is performed.

[0003]

However, a thin ceramic sintered product (workpiece) such as a piezoelectric substrate or a semiconductor substrate.
Has some warpage and undulations, and the upper and lower principal surfaces are not necessarily parallel and flat.

Therefore, when lapping is performed using the above lapping device, as shown in FIG. 7, if the workpiece 6 is warped or undulated, the workpiece 6 is mounted in the mounting hole 3a of the carrier 3. , The upper plate 1 is lowered and brought into contact with the workpiece 6, or the impact of the relative movement between the carrier 3 and the upper and lower plates 1 and 2 during the lapping process is locally applied to the workpiece 6. There is a problem in that the mechanical stress is applied, cracks and chips occur in the workpiece 6, and the yield rate decreases. Furthermore, in some cases, the surfaces of the upper and lower plates 1 and 2 and a part of the carrier 3 may be damaged.

The present invention solves the above-mentioned problems, and when the workpiece has a warp or undulation,
An object of the present invention is to provide a lapping method capable of preventing cracks and chips from being generated in a workpiece in the lapping step and performing good lapping without lowering the yield.

[0006]

In order to achieve the above object, the lapping method of the present invention mounts a workpiece on a carrier arranged between an upper plate and a lower plate,
With the workpiece and the upper and lower plates in contact with each other,
In the lapping method of lapping the workpiece by relatively moving the upper and lower plates and the carrier, a coating layer is formed on the surface of the workpiece so that both main surfaces thereof are substantially parallel to each other and substantially flat. After shaping, the shaped workpiece is mounted on a carrier, and the upper and lower plates and the carrier are relatively moved in a state where the upper and lower plates are in contact with both main surfaces of the carrier, and lapping is performed. .

[0007]

[Function] A coating layer is formed on the surface of the workpiece,
Since both main surfaces are shaped substantially parallel to each other and substantially flat,
In the process of lowering and contacting the upper plate with the shaped workpiece mounted on the carrier, or the process of lapping by moving the carrier and the upper and lower plates relative to each other, large local stress is applied to the workpiece. Can be reliably suppressed.

Therefore, it is possible to prevent cracking and chipping of the workpiece in the lapping process and improve the yield.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a method of lapping a piezoelectric substrate made of piezoelectric ceramic will be described as an example.

1 to 4 are views showing a lapping method according to an embodiment of the present invention. In this embodiment, first, as shown in FIG. 1, a piezoelectric substrate 6 having a warp or waviness on its surface is coated with, for example, an epoxy resin, and coating layers 10 are formed on both main surfaces thereof. Both principal surfaces are shaped substantially parallel to each other and substantially flat.

The coating material is not limited to epoxy resin, but polyvinyl alcohol, polyvinyl butyral, vinyl acetate emulsion, acrylic resin, and other materials to be processed are shaped so that local stress is exerted on the material during the lapping process. It is possible to suppress the addition,
In addition, it is possible to arbitrarily select and use various materials that do not particularly hinder lapping.

As the method of forming the coating layer 10, various methods such as coating, embedding, squeegee and the like can be applied.

In this embodiment, the coating layer 1
The average thickness (t) of 0 is 0.1 to 0.2 as shown below.
mm. Average thickness of coating layer (t) = (T−T ₀ ) /2=0.1 to 0.2 mm where T is the thickness (mm) of the shaped workpiece A, T ₀ is the thickness of the workpiece 6 ( mm) (see FIG. 1).

It should be noted that the thickness t of the coating layer 10 is not limited to the above-mentioned 0.1 to 0.2 mm, but an appropriate thickness is taken into consideration in consideration of the shape and type of the work piece, the state of warpage and waviness. It is possible to select.

As described above, the shaped workpiece A having the coating layer 10 formed on the surface thereof is lapped by using a lapping apparatus as shown in FIG. In that case, first, as shown in FIGS. 2 and 6, the carrier 3 mounted on the lower plate 2 is mounted in the mounting hole 3a. Then, the upper plate 1 is gradually lowered and brought into contact with the shaping workpiece A. 5 and 6, the description of the corresponding part in the description of the above-mentioned conventional technique is cited, and the description thereof will be omitted here.

At this time, the load of the upper plate 1 is not applied only to a local portion (for example, the position shown by X and Y in FIG. 2) of the workpiece 6, but is applied to the entire surface of the shaped workpiece A. Therefore, the stress applied when the upper plate 1 is brought into contact with the upper surface of the shaping work A can be relaxed.

Then, the carrier 3 and the upper and lower plates 1 and 2 are relatively moved to perform lapping. In this lapping step, as the lapping progresses, the projecting portion of the workpiece 6 along with the coating layer 10 is shaved, and as shown in FIG. 3, both main surfaces of the workpiece 6 are gradually flattened.

When the lapping step reaches the final stage, as shown in FIG. 4, the coating layers 10 on both main surfaces of the workpiece 6 are completely removed, and at the same time, both main surfaces of the workpiece 6 are removed. Warpage and undulations are also removed, both main surfaces of which are sufficiently parallel and flat, and processed into a predetermined thickness (dimension).

In the above embodiments, the piezoelectric substrate has been described as an example. However, the lapping method of the present invention is not limited to the piezoelectric substrate, and semiconductor substrates, dielectric substrates and various other thin plate-shaped workpieces can be lapped. Can be applied to.

The present invention is not limited to the above embodiment, but relates to the structures of the upper and lower plates and carriers, lapping conditions, etc., within the scope of the invention.
Various applications and modifications can be added.

[0021]

As described above, according to the lapping method of the present invention, a coating layer is formed on the surface of a workpiece and both main surfaces of the coating layer are shaped substantially parallel to each other and substantially flat, thereby forming a carrier. When making contact with the upper and lower plates, or when performing lapping by moving them relative to each other,
Preventing local stress from being applied to the work piece prevents cracks and chips from occurring in the work piece during the lapping process even when the work piece has warpage or undulations. As a result, good lapping can be performed without lowering the yield.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a shaped work piece having a coating layer formed on the surface of the work piece according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the shaping workpiece of FIG. 1 is mounted on a carrier and upper and lower plates are brought into contact with both main surfaces thereof.

FIG. 3 is a cross-sectional view showing a lapping process according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a state at the end of the lapping step according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a lapping device.

FIG. 6 is a plan view showing a carrier of the lapping device.

FIG. 7 is a cross-sectional view showing one step of a conventional lapping method.

[Explanation of symbols]

 1 Upper Plate 2 Lower Plate 3 Carrier 3a Mounting Hole 6 Workpiece 10 Coating Layer A Shaped Workpiece

Claims (1)

[Claims] 1. A work piece is mounted on a carrier disposed between an upper plate and a lower plate, and the work piece and the upper and lower plates are brought into contact with each other, and the upper and lower plates and the carrier. In the lapping method of lapping the workpiece by relatively moving and, a coating layer is formed on the surface of the workpiece, and both main surfaces of the coating layer are shaped substantially parallel and substantially flat with each other. A lapping method characterized in that an orthopedic workpiece is mounted on a carrier, and upper and lower plates are brought into contact with both main surfaces of the carrier, and the upper and lower plates and the carrier are relatively moved to perform lapping.