JPH09281016A - Wafer scriber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a device capable of easily performing cleavage when the cross section of a wafer is observed in order to confirm the process result in the production of a semiconductor by providing a cutter capable of accurately scribing the rear surface of the wafer. SOLUTION: A sample wafer 1 is fixed with a leaf spring 8 on the stage 7 movable on a rail 9 back and forth. A cutter 6 composed of a diamond needle passes through the groove 15 provided to the stage 7 to scribe the rear surface of the wafer 1. An optical system 10 such as a magnifying glass is provided above the stage 7 and the optical system 10 and the cutter 6 are connected so as to cooperate with each other or so that only the cutter 6 is independently moved. Collimation such as a cross is attached to the visual field of the optical system 10 and, if the cutter 6 is slid so as to be matched with the position to be cut of the surface of the wafer 1, the rear surface of the wafer is scribed at a desired position. If proper tension is applied to the wafer 1, the wafer is cleaved along a scribing line without damaging the sample wafer to perform necessary observation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to cleave a wafer at a desired position when observing a cross section of the wafer made of a compound semiconductor such as silicon, quartz or GaAs with a scanning electron microscope (SEM) or the like. The present invention relates to a device for scratching a wafer.

[0002]

2. Description of the Related Art In the field of the semiconductor industry, in order to confirm the results of various processes or to analyze the cause of defects, the cross section of a wafer made of semiconductor or the like is cleaved and SE
The cross section is often observed with M or the like. Conventionally, in such a case, as shown in FIG.
Make a scribe line (4) due to scratches on the wafer surface with a cutter (6) such as a diamond needle from the edge of the wafer to a target position in a direction perpendicular or parallel to the orientation flatness (2) of the wafer, and then apply an appropriate tension. The wafer is cleaved by applying a force (for example, applying a force in the direction of separating the left and right of the scratch).

However, when observing the cross-sectional shape of the surface such as a resist pattern by the above-mentioned method, the pattern (3) itself cannot be scribed in order to prevent the surface shape of the sample portion from being destroyed, so that scratching is not possible. A scratch or the like can be drawn only up to the vicinity of the pattern. in this case,
If tension is applied in that state, the degree of freedom in the direction of cleavage is large, so even if the pattern whose cross-section is to be observed exists continuously on a straight line, the pattern is not always cleaved as desired. For example, if a scribe line (4) due to a scratch is provided as shown in FIG. 5 (A) and tension is applied and cleavage is performed as shown in FIG. 5 (B), no problem occurs. ), The cleaved surface (5) is curved, and the cleaved surface passes through the sample portions 1 and 2 of the pattern portion, but other desired portions often come off the cleaved portion. there were. However, in evaluating the characteristics of the process equipment, it is not sufficient to observe only one or two sample points, and in order to grasp the continuous process change, a certain range (for example, line up on a straight line) It is important to be able to simultaneously observe samples having a different pattern by SEM or the like.

[0004]

Therefore, in the present invention, when the above-described pattern whose cross section is desired to be observed exists continuously on a straight line, all the patterns are stably observed so as to be surely observable. The present invention relates to a device that has been studied and developed for cleaving.

[0005]

To solve the above-mentioned problems, the subject matter of the invention of claim 1 of the present invention is to observe a wafer mounting table that can move in parallel on a rail and the surface of the wafer on the mounting table. And a cutter for attaching a scribe line to the back surface of the wafer under the observation position. According to the present invention, by adopting such a configuration, it is possible to accurately form a scratch on the back surface of the wafer.

Further, the gist of the invention of claim 2 of the present invention for solving the above-mentioned problems is the wafer scriber of claim 1 in which an optical system and a cutter can move in conjunction with each other. It is characterized by that. With this configuration, the scribe line can be correctly formed immediately below the observation position.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The apparatus of the present invention relates to an apparatus for accurately providing a scribe line not on the sample front surface side but on the back surface while observing the sample surface of the wafer surface when cleaving the wafer. Therefore, the apparatus of the present invention, the mounting table of the wafer as a sample, an optical system for observing the sample surface on the mounting table, and the system moves in conjunction with or independently of the optical system to scribe on the back surface of the wafer. It is composed of a cutter for providing lines.

The wafer mounting table is usually formed in a planar stage shape so that a flat wafer can be mounted. The stage has a wafer size of 2 to 1 in diameter.
It is desirable that a 2-inch object can be placed. It is desirable that the stage can be moved back and forth for scribing and can be slightly moved left and right for aligning the sample. The stage is provided with a standard line for aligning an orientation flat that reveals the crystal orientation of the wafer. The stage is configured to slide on two rails that maintain precision,
A groove is formed in the central portion of the stage so that the cutter can scribe the back surface of the wafer. The sample wafer is fixed on the stage by a strong fixing tool such as a leaf spring.

The optical system for observing the wafer may be a magnifying glass or the like having a relatively low magnification so that a large area of the wafer can be observed. The optical system may have its optical axis orthogonal to the wafer surface, or may be obliquely observed as shown in FIG. 1 if the optical system is a magnifying glass having a low magnification. It is preferable that the cutter is located below the intersection of the optical axis of the objective lens and the wafer surface. The scratch can be provided on the back surface of the wafer by fixing the stage and moving the optical system and the cutter in conjunction with each other, or by fixing the optical system and moving the stage in parallel. The distance between the cutter and the optical system needs to be adjustable in order to adjust the contact pressure of the cutter against the back surface of the wafer and the change in the thickness of the wafer. The cutter does not mean one that directly cuts a wafer, but it provides a scribe line such as a scratch as described above, and it is preferable to use a diamond needle for this.

[0010]

1 is a perspective view of an apparatus for a wafer scriber according to the present invention. FIG. 2 is a side view showing the structure of the wafer scriber of the present invention. An embodiment of the present invention will be described below with reference to FIGS. A wafer (1) as a test sample is fixed by a leaf spring (8) or the like on a stage (7) which can be moved back and forth on a rail (9) in the arrow direction. Wafer is the standard line (14) provided on the stage
Placed along with orientation flatness. This stage has a groove (15) in the center parallel to the rail.
Is provided, and the wafer can be scratched from the back surface of the wafer with a cutter (6) composed of a diamond needle through the groove. An optical system (10) such as a magnifying glass is provided above the stage, and is connected so that the magnifying glass and the cutter move together or only the cutter moves independently. In the field of view of the magnifying glass,
A cross mark or a circle mark is attached for collimation, and you can scribe a desired position on the back side by aligning this cross mark with the position you want to cut on the wafer surface and sliding the cutter. . Finally, by removing the wafer from the stage and applying an appropriate tension, the wafer can be cut along the scratches.

As shown in FIG. 2, the wafer scriber of the present invention includes a screw (11) for sliding the stage on the rail, a screw (13) for vertically moving the optical system (10), and a cutter. Alternatively, a screw (12) for moving the optical system back and forth is provided so that a predetermined position on the wafer can be observed and a predetermined position can be scribed by a cutter.

FIG. 3 shows a scribe line (4) on a sample wafer (1) using the wafer scriber according to the present invention.
It shows a situation in which the blade was formed by a cutter (6) composed of diamond needles. In the conventional method shown in FIG.
Although the scribe line could be inserted only near the pattern (3), in the case of FIG. 3, the scribe line (4) can be formed on the back surface sufficiently long, so that the cleavage cannot be successful. Rarely occurs.

[0013]

As described above, according to the wafer scriber of the present invention, a scribe line for cleavage can be accurately provided on the back surface of the wafer, and necessary observation can be performed without damaging the sample on the wafer surface. It can be carried out.

[Brief description of drawings]

FIG. 1 is a perspective view showing a wafer scriber of the present invention.

FIG. 2 is a side view showing the configuration of the wafer scriber of the present invention.

FIG. 3 is a perspective view showing a state in which a scribe line is provided on the back surface of a sample wafer in the wafer scriber of the present invention.

FIG. 4 is a perspective view showing a situation in which a scribe line is provided on the surface of a sample wafer by a conventional method.

FIG. 5 is a perspective view showing a step of cleaving a sample wafer by a conventional method.

[Explanation of symbols]

 1 wafer 2 orientation flatness 3 pattern 4 scribe line 5 cleavage plane 6 cutter 7 stage 8 leaf spring 9 rail 10 optical system 11 stage sliding screw 12 forward or backward moving screw of cutter or optical system 13 vertical moving screw of optical system 14 standard line 15 Stage groove

Claims (2)

[Claims] 1. A wafer mounting table capable of moving in parallel on a rail, an optical system for observing the front surface of the wafer on the mounting table, and a cutter for attaching a scribe line to the back surface of the wafer under the observation position. Wafer scriber that is characterized by 2. The wafer scriber according to claim 1, wherein the optical system and the cutter move in an interlocking manner.