JP2001300869A - Scribing line forming device for wafer cleavage - Google Patents

Abstract

(57) [PROBLEMS] To provide an apparatus for forming a scribe line for cleaving a wafer so that the wafer surface can be cleaved accurately even while protecting the wafer surface, even for a brittle and fragile wafer. A scribe line forming apparatus for cleaving a wafer of the present invention is provided.
Is provided with a gantry 12 and a cutter 14 at an upper end thereof, and a cutter holder 16 that stands upright and is movable in the X direction. A movable body that supports the cutter holder in the X direction and is movable in the Y direction. A table 18, a wafer holding table 20 disposed above the cutter and holding a wafer, and a laser beam emitting device 24 provided at an upper end of a column 22 extending upright from one end of the moving body and extending upward. , A transparent dummy wafer. Before forming a scribe line on a wafer, a dummy wafer is placed on a wafer holding table, the cutter is positioned by irradiation of laser light from a laser light emitting device, and then a scribe line is formed on the back surface of the wafer by the cutter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for forming a scribe line for cleaving a wafer, and more particularly, to a method for forming a scribe line along a predetermined line on the back surface of a wafer. The present invention also relates to a scribe line forming apparatus for cleaving a wafer and a method therefor.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a wafer is cleaved and the cleavage surface of the wafer is subjected to scanning electron microscopy (SEM) or Auger electron spectroscopy in order to check the quality of the wafer after a predetermined process step. In many cases, the cleavage plane is inspected and analyzed visually. In addition, when inspecting not only the cleavage plane but also the pattern formation state of the wafer surface with an electron microscope or the like, the wafer on which the pattern is formed is formed in order to produce a wafer sample having a size that allows the wafer sample to be easily mounted on a sample stage of the electron microscope. Is often cleaved to produce a wafer sample of a predetermined size.

For example, when a wafer is prepared by cleaving a silicon wafer to inspect a pattern formation surface or a cleavage surface of the silicon wafer, the wafer surface (working surface) or the back surface of the wafer faces downward. Then, place the wafer on a predetermined cleavage plate, mark it with a marker along the line to be cut, or apply a ruler, form a scribe line with a diamond pen or the like, and face down to the wafer area near the scribe line. The wafer is cleaved along the scribe line by applying a load of.

Further, a GaAs wafer is cleaved by a method different from that of a silicon wafer. Here, a conventional method of cleaving a compound semiconductor wafer such as a GaAs wafer will be described with reference to FIGS. FIG. 6 (a)
7 (c) and 7 (d) and 7 (e) are schematic diagrams showing procedures for cleaving a GaAs wafer by a conventional method. In this example, in order to inspect and analyze a pattern formation state of a pattern region where a pattern of a semiconductor device is formed by an electron microscope, a wafer cleavage when a wafer sample placed on a sample stage of the electron microscope is manufactured by cleavage of the wafer. Is taken as an example. It is assumed that the width of the wafer sample is substantially the same as the width of the orientation flat. First, when it is desired to cleave the wafer 40 shown in FIG. 6A, as shown in FIG. 6B, a diamond cutter or the like is set at the intersection between the line to be cut and the orientation flat 41 of the wafer 40, for example, points A and B. Make a cut with. Next, as shown in FIG. 6C, the wafer portions 40a outside the cut points A and B,
The wafer portion 40c is gripped and divided by tearing, and the central wafer portion 40c is separated.

Subsequently, in order to obtain a wafer sample in a pattern region where a pattern of a semiconductor device is formed, FIG.
As shown in (d), a scribe line is scribed with a diamond pen along a horizontal cut line of the pattern region of the wafer portion 40c, and cleaved along the scribe line in the same manner as the above-described vertical cleavage of the wafer. And the wafer portions 42a-42
Obtain d. Next, the wafer portions 42a to 42d are cleaved so that the height of the wafer sample is adjusted to about 10 mm in order to make the size easily mountable on the sample stage of the electron microscope.
The wafer samples 44a to 44c shown in FIG.

[0006]

However, the conventional wafer cleavage method has the following problems. A first problem is that when cleaving a GaAs substrate, it cannot be cleaved along a desired line. In the cleavage of the GaAs substrate, a cleavage line is made in the peripheral portion of the wafer, and the wafer is cleaved so as to be torn therefrom. Therefore, the cleavage line depends on the growth direction of the wafer crystal. As a result, it is difficult to cleave straight along a desired line orthogonal to the orientation flat, and for example, as shown in FIG. 8, the cleavage line between 40b and 40c is often inclined and broken.
The second problem is that since the dimensions that can be confirmed by the eye are at most mm units, not only GaAs wafers and silicon wafers, but also, when cleaving the wafer, an accurate scribe line is formed in the pattern area by visually observing the wafer sample. It is difficult.

The third problem is that the wafer surface (pattern surface)
When a scribe line is formed, there is a high possibility that a pattern surface to be inspected and analyzed is damaged, and a chip of a wafer becomes dust and contaminates the pattern surface to be inspected. Also, when a scribe line is formed on the back surface of the wafer, the downwardly facing surface of the wafer is pressed against a cutting plate (wafer mounting table), which causes a problem that the wafer surface is scratched and the pattern surface is destroyed. is there. The fourth problem is that, because of various problems as described above, the wafer cleavage requires skill and experience, and individual differences occur.

In particular, compound semiconductor wafers such as GaAs wafers are brittle and easily broken. When a cut or scribe line is formed with a diamond pen or the like, cracks are formed on the wafer by the point pressure of the diamond pen or the like during formation of the scribe line. Easy to occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and a method for forming a scribe line for cleaving a wafer so that the wafer surface can be cleaved accurately while protecting the wafer surface, even if the wafer is brittle and easily broken. It is to be.

[0010]

In order to achieve the above object, a scribe line forming apparatus for cleaving a wafer according to the present invention comprises:
A scribing line forming apparatus for drawing a scribing line for cleaving a wafer on the back surface of a wafer, comprising a movable table movable in a Y direction and a cutter at an upper end portion, and standing upright on the movable table to be slid in the X direction. A flexible cutter holder, a dummy wafer for cutter positioning formed of a transparent material and having the same thickness as the wafer, and a wafer positioned horizontally above the cutter and having an opening on the bottom plate with the wafer back face down. A wafer holding table for holding the
A laser light emitting device that is provided so as to move integrally with the moving body, is placed on the wafer holding table, and then irradiates the wafer with laser light at a point, and before forming a scribe line on the wafer. A dummy wafer is placed on a wafer holding table, and a cutter is positioned by laser light emitted from a laser light emitting device.

In the present invention, before forming a scribe line on a wafer, a dummy wafer is placed on a wafer holding table, and the cutter is moved in the X direction to irradiate a laser light irradiation point from the laser light emitting device with the cutter. Is aligned and positioned, it is possible to set a desired line on which a scribe line is to be formed while confirming the pattern formed on the wafer surface, and position the cutter at that line. Also,
By moving the moving table in the Y direction, a scribe line can be formed on the back surface of the wafer along a desired line by the cutter.

The scribe line forming apparatus for cleaving a wafer according to the present invention can be applied to not only a silicon wafer but also a compound semiconductor wafer such as a GaAs wafer, a GaN wafer, an InP wafer or the like, which is easily damaged at the time of cleavage, and a ferrite substrate. Can also be applied. When the scribe line forming apparatus for cleaving a wafer according to the present invention is used, cleaving can be performed accurately and without any individual difference while protecting the pattern and cleaved surface on the wafer surface.

Preferably, the cutter holder includes fixing means for fixing the cutter to the moving table, and an elastic body fixed by the fixing means at a position where the cutter is positioned, and for urging the cutter upward. Through the opening, and presses the cutter against the back surface of the wafer. This makes it possible to more reliably form the scribe line on the back surface of the wafer. Further, a linear guide is provided below the moving base, and a moving means for slidably moving the moving base in the Y direction on the linear guide is provided. Thereby, the cutter can be smoothly and correctly Y-shaped.
The scribe line can be formed along a desired line because it can move in the direction. Further, a counterbore recess for accommodating a wafer is provided in the wafer holding table. This allows
The wafer can be accurately positioned on the wafer holder and accommodated. There is no limitation on the type of cutter as long as the scribe line can be formed. For example, a diamond pen can be used as the cutter.

In a method of forming a scribe line according to the present invention, a transparent dummy wafer for positioning a cutter having the same thickness as a wafer is placed on a horizontal wafer holding table and moved in the Y direction integrally with the cutter. Activating the laser light emitting device to irradiate the dummy wafer with laser light, and then moving the cutter below the dummy wafer in the X direction to align the laser light irradiation point on the dummy wafer with the cutter. Fixing the cutter at the aligned position, placing the wafer to be cleaved on the wafer holding table in place of the dummy wafer, and moving the cutter in the Y direction to form a scribe line on the back surface of the wafer. And characterized in that: The scribe line forming method for cleaving a wafer according to the present invention can be applied not only to a silicon wafer, but also to a compound semiconductor wafer such as a GaAs wafer, a GaN wafer, or an InP wafer, which is easily damaged during cleavage, and further to a ferrite substrate. .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the accompanying drawings based on embodiments. Embodiment the present embodiment of the wafer cleavage for marking line forming apparatus is an example embodiment of the scribe line forming apparatus for wafer cleaved according to the present invention. FIG. 1 is a perspective view of a scribe line forming apparatus for cleaving a wafer according to this embodiment, FIG. 2 is a front view of the scribe line forming apparatus for cleaving a wafer according to this embodiment, and FIG. FIGS. 4A and 4B are a plan view and a side view of the dummy wafer, respectively. A scribe line forming apparatus 10 for cleaving a wafer according to the embodiment (hereinafter, simply referred to as a scribe line forming apparatus 10).
As shown in FIGS. 1 and 2, the gantry 12 and the cutter 1
A cutter holder 16 having an upper end 4 and movable upright and movable in the X direction; a movable base 18 supporting the cutter holder 16 movably in the X direction and movable in the Y direction; And a laser beam emitting device 2 provided at an upper end of a column 22 extending upward from one end of the moving body 18 and standing upright from one end of the moving body 18.
4 is provided.

The gantry 12 includes an upper stage 12a on which the wafer holder 20 is placed horizontally and a lower stage 12b for supporting the moving stage 18.
And The wafer holder 20 is a plate-like body that horizontally holds a cleaved wafer, holds a wafer W,
As shown in FIG. 3, a counterbore 20a having the same shape as the wafer W is provided so as not to be displaced, and a cutter blade of the cutter 14 is pierced and penetrated in a central region of the counterbore. An opening 26 is provided so that the cutter blade travels along a predetermined line.

The cutter 14 has a cutter blade at its upper end and is held upright on the upper end of a cutter holder 16. The cutter holding body 16 includes a holding plate 16a for holding the cutter 14 upright, a coil spring 16c interposed between the holding plate 16a and the bottom plate 16b, and a long hole 18a in the X direction provided on the moving table 18. It has a lower end 16d penetrating therethrough and a knurled screw 16e provided on the lower end 16d. The cutter blade of the cutter 14 causes the opening 2 of the wafer holder 20 to be moved by the spring force of the coil spring 16c interposed between the bottom plate 16b of the cutter holder 16 and the holding plate 16a.
6 and comes into contact with the back surface of the wafer W with an appropriate pressing force. Also, the cutter holder 16 is provided with a knurled screw 16e.
Is fixed to the movable table 18 at a predetermined position.

The movable table 18 is formed of a plate-like body, and has a long hole 1 in the X direction penetrating the lower end 16 d of the cutter holder 16.
8a, and slides on the lower stage 12b of the gantry 12. The column body 22 has a movement knob 28 in the middle, and the movement knob 28
Is moved in the Y direction with the moving member 18, thereby moving in the Y direction integrally with the moving body 18. Further, by rotating the moving knob 28, the column 22 and the moving body 18 can be moved in the Y direction. Here, the Y direction is a direction orthogonal to the paper surface in FIG. 1 and a direction of an arrow Y in FIG. The X direction is the direction of the arrow X in FIGS.

As shown in FIGS. 2 and 5, the laser light emitting device 24 is a device that emits laser light. The laser light emitting device 24 is located at a position on the wafer surface opposite to the wafer back surface where the cutter blade of the cutter 14 contacts. A laser beam is irradiated.
The laser beam emitting device 24 is connected to a cutter 14 to be described later.
In order to increase the accuracy of the alignment with the laser beam, a laser pointer is provided so that the irradiation point on the wafer is reduced, and the angle of attachment is adjusted to adjust the emission angle of the laser beam.

The moving knob 28 is provided on a support plate 22 a extending inward from the center of the column 22, while the support plate 22 a is connected to the upper stage of the gantry 12 via a linear guide (LM guide) 30. 12a is slidably supported in the Y direction. Further, in order to make the movable table 18 slidably travel in the Y direction, the movable table 18 is connected to the lower stage 12 of the gantry 12 via linear guides (LM guides) 32A and 32B at both ends.
b. In order to prevent the mounted wafer from moving, two inverted L-shaped wafer pressing plates 34 made of resin are provided on the wafer holding table 20 so as to cover both peripheral portions of the wafer W as shown in FIG. It is provided so as to extend in the Y direction across it. Further, a stopper (not shown) is provided so that the wafer pressing plate 34 does not strongly press the wafer surface. Incidentally, a vacuum suction mechanism may be provided on the wafer holding table 20 in order to hold the wafer so as not to move.

The scribing line forming apparatus 10 includes a dummy wafer for positioning in order to align an irradiation spot on the wafer of the laser beam emitted from the laser beam emitting device 24 with the cutter blade of the cutter 14. 36.
The dummy wafer 36 is a transparent resin plate, and has the same outer shape and the same thickness T as the wafer W, as shown in FIGS. 4A and 4B.

Before forming the scribe line on the wafer, a dummy wafer 36 is placed on the wafer holding table 20 and the cutter 14 is positioned so that the irradiation spot of the laser beam from the laser beam emitting device 24 and the cutter 14 are aligned. Move the holding body 16 to the moving table 18
Slide in the X direction above and then lock in the aligned position. Next, by moving the movable table 18 in the Y direction, a scribe line can be formed on the back surface of the wafer by the cutter 14. According to the above configuration, a scribe line for cleaving the wafer can be formed on the back surface of a fragile and easily damaged compound semiconductor wafer or the like with high precision and without individual differences among operators. In this embodiment, the chip
By separately using an oblique light device in order to easily confirm the pattern position on the wafer surface on which the pattern is formed, the scribe line forming operation can be further facilitated.

An embodiment of a scribe line forming method for cleaving a wafer
Embodiment This embodiment is an example of an embodiment to which the method for forming a scribe line for cleaving a wafer according to the present invention using the above-described scribe line forming apparatus 10 is applied. FIG. 5 is a conceptual diagram showing the relationship between the laser light emitted from the laser light emitting device and the cutter. In the method of the present embodiment, first, the dummy wafer 3 is placed on the counterbore recess 20a of the wafer holding table 20.
6, the laser light emitting device 24 is activated, and the dummy wafer 36 is irradiated with laser light. The irradiation position is a position of the dummy wafer 36 corresponding to a scheduled line for forming a scribe line of the wafer. Next, while observing the irradiation point of the laser beam applied to the dummy wafer 36,
The cutter holder 16 is moved upward in the X direction, and the irradiation point of the laser beam irradiated from the laser beam irradiation device 24 and the cutter blade of the cutter 14 are aligned as shown in FIG. When the alignment is completed, the cutter holder 16
The knurled screw 16e of the cutter holder 16 and the cutter 14
Is fixed.

Next, the dummy wafer 36 is taken out of the wafer holder 20, and the wafer to be cleaved is placed on the wafer holder 20.
On the counterbore recess 20a. At the time of mounting, the wafer is mounted so that the orientation flat of the wafer is parallel to the X direction. Then, the wafer is pressed by the wafer pressing plate 34 in a region outside the scribe line forming region. Thus, the cutter blade of the cutter 14 comes into contact with the back surface of the wafer in a state where the cutter blade is aligned with the irradiation point of the laser beam. Next, when the moving body 28 is moved in the Y direction while holding the moving knob 28, the moving body 18 and the cutter holder 16, that is, the cutter 14 are moved in the Y direction, and a scribe line is formed on the back surface of the wafer. Next, the wafer on which the scribe line is formed is taken out of the wafer holding table 20, and the wafer is held with both hands across the scribe line, and is pulled to tear right and left.
The wafer is cleaved along the scribe line to obtain a desired wafer sample.

When the cleaved wafer sample is further cleaved, another transparent dummy wafer having the same outer shape and thickness as the wafer sample is placed on the wafer holding table, and the cutter 14 is positioned by the above-described method. Then, the wafer is placed on the wafer holding table such that the planned scribe line is parallel to the Y direction, and thereafter, a wafer sample having a desired size is manufactured in the same manner.

[0026]

According to the present invention, there is provided a cutter holder having a cutter, which is slidable in the X direction, a movable table, a dummy wafer, a wafer holder, and a laser beam emitting device for irradiating a laser beam with a point. Before forming the scribe line of the wafer,
A dummy wafer is placed on a wafer holder, the cutter is positioned by laser light from a laser beam emitting device, and then a scribe line is formed on the back surface of the wafer by the cutter to accurately detect brittle and easily damaged compound semiconductor wafers. well,
A scribe line for cleaving a wafer can be formed without individual differences between workers. The scribe line forming apparatus for cleaving a wafer according to the present invention can be cleaved without damaging the wafer and the pattern region on the surface of the wafer, so that a high-quality wafer sample in which the pattern region is not contaminated with dust or the like can be produced. can do. The scribing line forming apparatus for cleaving a wafer according to the present invention includes, in addition to a silicon wafer, a GaAs wafer, a GaN wafer,
The present invention can be applied to a compound semiconductor wafer such as an nP wafer and a ferrite substrate. The method of the present invention realizes a method of forming a scribe line, which can be cleaved without damaging a wafer and a pattern region on the wafer surface.

[Brief description of the drawings]

FIG. 1 is a perspective view of a scribe line forming apparatus for cleaving a wafer according to an embodiment.

FIG. 2 is a front view of a scribe line forming apparatus for cleaving a wafer according to the embodiment.

FIG. 3 is a plan view of a wafer fixing table.

FIGS. 4A and 4B are a plan view and a side view of a dummy wafer, respectively.

FIG. 5 is a conceptual diagram showing a relationship between a laser beam emitted from a laser beam emitting device and a cutter.

6 (a) to 6 (c) are schematic diagrams each showing a procedure for cleaving a wafer by a conventional method.

7 (d) and (e) are FIGS. 6 (c), respectively.
FIG. 9 is a schematic view showing a procedure for cleaving the wafer by a conventional method, following FIG.

FIG. 8 is a diagram illustrating a problem when a wafer is cleaved by a conventional method.

[Explanation of symbols]

10 wafer scribing line forming apparatus of the embodiment,
12 ... stand, 12a ... upper, 12b ... lower, 14
... Cutter, 16 Cutter holder, 16a Holding plate, 16c Coil spring, 16d Lower end, 16e
... knurled screw, 18 ... moving table, 18a ... long hole, 20 ... wafer holding table, 20a ... counterbore recess, 2
2 ... column, 24 ... laser beam emitting device, 26 ... opening, moving knob, 30 ... linear guide (LM guide), 32A, B ... linear guide (LM guide), 3
4 ... Wafer holding plate, 36 ... Dummy wafer, 40 ...
... wafer, 42 ... wafer portion.

Claims (6)

[Claims] 1. A scribe line forming apparatus for drawing a scribe line for cleaving a wafer on the back surface of a wafer, comprising: a movable table movable in a Y direction; A cutter holder that is foldable in the X direction, a cutter positioning dummy wafer formed of a transparent material and having the same thickness as the wafer, and a wafer rear face down on a bottom plate having an opening and disposed above the cutter. A wafer holder that holds the wafer horizontally, and a laser beam emitting device that is provided so as to move integrally with the moving body, and that irradiates the laser beam with a point on the dummy wafer placed on the wafer holder, and then irradiates the wafer with a point. Before forming the scribe line of the wafer, a dummy wafer is placed on the wafer holding table, and the cutter is positioned by the laser light emitted from the laser light emitting device. Scribe line forming device for cleaving wafers. 2. A wafer holding table, comprising: a fixing means for fixing the cutter holder to the moving table; an elastic body fixed by the fixing means at a position where the cutter is positioned; and an elastic body for urging the cutter upward. The scribe line forming apparatus for cleaving a wafer according to claim 1, wherein the cutter is pressed against the back surface of the wafer through the portion. 3. The wafer cleaving device according to claim 1, further comprising a linear guide provided below the moving table, and moving means for slidably moving the moving table in the Y direction on the linear guide. Scribe line forming equipment. 4. The scribing line forming apparatus for cleaving a wafer according to claim 1, wherein a counterbore having the same shape as the outer shape of the wafer is provided in the wafer holding table, and the wafer is accommodated in the counterbore. 5. The scribe line forming apparatus for cleaving a wafer according to claim 1, wherein the cutter is a diamond pen. 6. A transparent dummy wafer for positioning the cutter having the same thickness as the wafer is placed on a horizontal wafer holding table, and a laser beam emitting device that moves in the Y direction integrally with the cutter is started. Irradiating the dummy wafer with laser light, and then moving the cutter below the dummy wafer in the X direction,
Positioning the laser beam irradiation point on the dummy wafer with the cutter; fixing the cutter at the aligned position; placing the wafer to be cleaved on the wafer holding table in place of the dummy wafer; Forming a scribe line on the back surface of the wafer by moving in the Y direction.