JPH10229112A - Mask alignment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mask alignment device which can project light from the backside of a wafer, without being restricted by the structure. SOLUTION: A transparent thin plate 3, which does not transmit ultraviolet rays is positioned to cover the entire area of the wafer-mounting surface of a wafer chuck 1. The thin plate 3 has wafer vacuum holes 2, formed through the plate 3 at the locations corresponding to the holes 2 of the wafer chuck 1. High-luminance high-density LED arrays comprising a plurality of light- emitting diodes are housed in the wafer chuck 1, have rectangular shapes, so that the arrays 4 can be faced to each other on both sides of the holes 2 and arranged, so that the arrays 4 project light from the backside of the wafer, when the wafer is mounted on the chuck 1. The arrays 4 are connected to an external power source 6 via conductors 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a mask alignment apparatus used in a photolithography process of a light transmitting wafer.

[0002]

2. Description of the Related Art In a mask alignment apparatus used in a semiconductor process (photolithography step) for a silicon wafer or the like, an oblique light from an objective lens illuminates an alignment mark on a wafer and an alignment mark on a photomask so that the two coincide. Do the work.

However, recently, not only silicon but also various materials have been supplied in the form of wafers, and the necessity of enabling various mask alignment operations has been increasing.

A single crystal ferroelectric wafer is used as the above-mentioned wafer. As a means for machining this wafer, there is a sand blast method which has been used exclusively in a plasma display panel manufacturing process.

In the sand plast method, it is necessary to separate processed / non-processed areas of a wafer by a resist pattern. The thickness of a resist film used at this time is used in the above-described semiconductor process for a silicon wafer or the like. It is not as thin (about 10 μm) as the resist film, but about 5 to 10 times as thick.

Accordingly, in order to recognize the alignment marks on both the wafer and the photomask by the oblique light from the objective lens, the focal lengths differ greatly between the two, and the light is attenuated (absorbed) inside the resist. Difficult for reasons.

Here, since the single crystal ferroelectric wafer is transparent or translucent to visible light, it is possible to transmit light from the back side of the wafer, and to shine light from the back side of the wafer and transmit the light. The above problem can be solved by introducing light into the objective lens.

As described above, the mask alignment apparatus used in the patterning (photolithography) step of a light-transmitting wafer coated with a thick (50 to 100 μm) resist irradiates at least the vicinity of the alignment mark to a wafer chuck on which the wafer is set. It is necessary to have a light emitting region that can be used.

Therefore, a method of performing a mask alignment operation using the back surface light of the double-sided mask aligner has been attempted. However, in order to perform the operation with higher versatility and at a low cost, a normal (one-sided) It needs to be able to do with a mask aligner.

As a method for solving the above problem, there is a mask alignment apparatus shown in FIG. 1 is a wafer chuck on which a wafer is mounted, 2 is a wafer suction hole for vacuum suction of the wafer, 9 is a light emitting surface, and 10
Denotes an optical fiber, and light passing through the optical fiber 10 is emitted from the light emitting surface 9. Reference numeral 11 denotes a filter for cutting ultraviolet light, and reference numeral 12 denotes a halogen bulb. Here, the reason why the filter 11 is provided is that the resist is exposed by ultraviolet light.

A conventional mask alignment apparatus is
A wafer (not shown) is mounted on the wafer mounting surface 1, and ultraviolet light of the light emitted from the halogen bulb 12 is filtered by the filter 11.
The light from which the ultraviolet light has been removed is
The light is emitted from the back side of the wafer by irradiating from the light emitting surface 9 through the inside.

[0012]

However, in the mask alignment apparatus having the above-described structure, there is a problem in that the place where the bundle of optical fibers 10 is inserted into the wafer chuck 1 is considerably restricted.

Further, once inserted, the light emitting position (light emitting surface 9) cannot be arbitrarily changed, so that it can be used for a wafer of any size or a wafer having an alignment mark at an arbitrary position. There was a problem that can not be.

The present invention has been made in view of the above points, and an object of the present invention is to provide a mask alignment apparatus capable of irradiating light from the back side of a wafer without being limited to a structure. Is to do.

[0015]

According to the first aspect of the present invention,
A mask alignment device for aligning a wafer, comprising: a wafer chuck for mounting a wafer; a suction unit for suctioning a wafer mounted on the wafer chuck; and a built-in wafer chuck mounted on the wafer chuck. LE arranged to irradiate light from the back side of the wafer
It has a D array and a power supply connected to the LED array via a conducting wire.

According to a second aspect of the present invention, in the mask alignment apparatus of the first aspect, an LED array is arranged on substantially the entire surface of the wafer chuck on the wafer mounting surface.

According to a third aspect of the present invention, in the mask alignment apparatus according to the first or second aspect, the L
The ED array is divided into a plurality of parts, and a selective lighting circuit for performing lighting control for each of the divided LED array groups is added.

According to a fourth aspect of the present invention, in the mask alignment apparatus according to the first or third aspect, the L
The ED array is arranged on the wafer mounting surface of the wafer chuck in a substantially cross shape.

According to a fifth aspect of the present invention, in the mask alignment apparatus according to any one of the first to fourth aspects, the LE is provided.
A blinking circuit for controlling blinking of the D array is added.

According to a sixth aspect of the present invention, in the mask alignment apparatus according to the first to fifth aspects, the LE is provided.
The emission wavelength range of the D array is in the range of 570 to 610 nm.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 = FIG. 1 is a schematic view showing a mask alignment apparatus according to an embodiment of the present invention. 1 is a wafer chuck,
Reference numeral 2 denotes a wafer suction hole as a suction unit for sucking a wafer, and 3 denotes a transparent thin plate that does not transmit ultraviolet light, and is arranged so as to cover the entire wafer mounting surface of the wafer chuck 1. At this time, the wafer suction holes 2 are also formed in the transparent thin plate 3 at locations corresponding to the wafer suction holes 2 in the wafer chuck 1. Reference numeral 4 denotes a high-brightness, high-density LED array composed of a plurality of light-emitting diodes. The LED array 4 is housed inside the wafer chuck 1 and has a rectangular shape so as to substantially face the wafer chucking hole 2. When the wafer is mounted on the wafer 1, it is arranged to emit light from the back surface of the wafer. The LED array 4 is connected to an external power supply 6 by a conductor 5.

Here, the thickness of the wafer chuck 1 is about 1c.
m, and the thickness of the LED array 4 is about 5 to 7 mm, so that the LED array 4 is completely embedded in the wafer chuck 1.

Therefore, in the present embodiment, the LED array 4 is built in the wafer chuck 1 on which a wafer (not shown) is mounted, and light emitted from the LED array 4 emits light from the alignment mark on the wafer and its vicinity. , The exposed portion of the wafer chuck 1 is only the conductive wire 5 and has a very compact structure, and its specifications are not limited by the structure of the mask alignment apparatus.

Embodiment 2 = FIG. 2 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention. For convenience of description, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The wafer alignment device according to the present embodiment has a configuration in which the LED array 4 in the wafer alignment device according to the first embodiment is arranged on substantially the entire surface of the wafer mounting surface of the wafer chuck 1 except for the portion where the wafer suction hole 2 is formed. It is.

Therefore, in the present embodiment, the LED array 4 is built in the wafer chuck 1 on which a wafer (not shown) is mounted, and light emitted from the LED array 4 emits light from the alignment mark on the wafer and its vicinity. , The exposed portion of the wafer chuck 1 is only the conductive wire 5 and has a very compact structure, and its specifications are not limited by the structure of the mask alignment apparatus.

Also, since the LED array 4 is arranged on almost the entire surface of the wafer mounting surface of the wafer chuck 1 except for the location where the wafer suction hole 2 is formed, the LED array 4 can be used depending on the wafer size and the alignment mark position of the wafer. There is no restriction.

In this embodiment, two LED arrays 4 are arranged on the wafer mounting surface of the wafer chuck 1. However, the present invention is not limited to this. For example, as shown in FIG. The vicinity of the center of the two LED arrays 4 shown in FIG.
The ED array 4 may be used. In this case,
The connection between the LED array 4 and the external power supply 6 can be performed by one conductor 5.

Embodiment 3 = FIG. 4 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention. For convenience of description, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The mask alignment apparatus according to the present embodiment is the same as the mask alignment apparatus shown in FIG.
In this configuration, the ED array 4 is divided into a plurality of parts, and each LED array 4 is connected to a selective lighting circuit 7 via a conductor 5. Here, the selective lighting circuit 7 selects which LED array 4 is to be supplied with the supply voltage from the external power supply 6, and controls the selective lighting circuit 7 to turn on a desired LED array 4. it can.

Therefore, in the present embodiment, the LED array 4 is built in the wafer chuck 1 on which a wafer (not shown) is mounted, and the light emitted from the LED array 4 emits light from the alignment mark of the wafer and its vicinity. , The exposed portion of the wafer chuck 1 is only the conductive wire 5 and has a very compact structure, and its specifications are not limited by the structure of the mask alignment apparatus.

Further, since the LED array 4 is arranged on substantially the entire surface of the wafer mounting surface of the wafer chuck 1 excluding the portion where the wafer suction hole 2 is formed, the LED array 4 can be used depending on the wafer size and the alignment mark position of the wafer. There is no restriction.

Further, a desired LED is provided by the selective lighting circuit 7.
Since the array 4 is turned on, it can be operated with the minimum power consumption by turning on the light according to the alignment mark position of the wafer, and by generating a specific light emitting pattern, It is also possible to display a guide.

The arrangement pattern of the LED array 4 is as follows.
The arrangement pattern of the LED array 4 in the present embodiment is not limited. For example, as shown in FIG. 5, the LED array 4 is arranged substantially at the center of the wafer chuck 1, and the LED array 4 arranged substantially at the center is provided. May be formed to sandwich the wafer suction hole 2.

Embodiment 4 = FIG. 6 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention. For convenience of description, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The mask alignment apparatus according to the present embodiment has a configuration in which the LED array 4 in the mask alignment apparatus shown in FIG. 4 as the third embodiment is arranged on the wafer mounting surface of the wafer chuck 1 so as to have a substantially cross shape.

Therefore, in this embodiment, the LED array 4 is built in the wafer chuck 1 on which a wafer (not shown) is mounted, and the light emitted from the LED array 4 emits the alignment mark on the wafer and its vicinity. , The exposed portion of the wafer chuck 1 is only the conductive wire 5 and has a very compact structure, and its specifications are not limited by the structure of the mask alignment apparatus.

Further, a desired LED is provided by the selective lighting circuit 7.
Since the array 4 is turned on, it can be operated with minimum power consumption by turning on according to the alignment mark position of the wafer. Further, since the LED array 4 is arranged in a substantially cross shape, The light emission of the LED array 4 arranged in the mold functions as a guide when the wafer is mounted on the wafer chuck 1, and the wafer can be mounted on the wafer chuck 1 very efficiently and accurately.

In this embodiment, a plurality of LEs
Although the D-shaped array 4 forms a substantially cross-shaped array, the present invention is not limited to this. A substantially cross-shaped array may be formed by one LED array 4. In this case, the selective lighting circuit 7 may be omitted. At the same time, the connection between the LED array 4 and the external power supply 6 can be performed by one conductor 5.

In general, a person can obtain approximately twice the visibility in the case of blinking as compared with the case of lighting, so that the L in the first to fourth embodiments can be obtained.
If the ED array 4 is made to blink, the visibility is further improved. For example, as shown in FIG. 7, in a mask alignment apparatus shown in FIG. To the LED
If the light emission of the array 4 is made to blink, the visibility is improved and the wafer can be mounted on the wafer chuck 1 with higher accuracy.

Here, in the first to fourth embodiments, the LED
By setting the emission wavelength peak value of each light emitting diode constituting the array 4 to be in a range of 560 to 610 nm (yellow to orange), it is possible to cut short wavelengths such as when white light is used as a light source. (The transparent thin plate 3 in the first to fourth embodiments) becomes unnecessary.

[0040]

According to the first aspect of the present invention, there is provided a mask alignment apparatus for positioning a wafer, comprising: a wafer chuck for mounting a wafer; a suction unit for suctioning the wafer mounted on the wafer chuck; Since it has an LED array arranged to irradiate light from the back side of the wafer mounted on the wafer chuck and a power supply connected to the LED array via a lead wire,
The portion exposed from the wafer chuck is only a conductive wire and has a very compact structure, and a mask alignment apparatus capable of irradiating light from the back side of the wafer without being limited to the structure can be provided.

According to the second aspect of the present invention, in the mask alignment apparatus of the first aspect, since the LED array is arranged on substantially the entire surface of the wafer mounting surface of the wafer chuck, use of the LED array is restricted depending on the wafer size and the alignment mark position of the wafer. Never be.

According to a third aspect of the present invention, there is provided a mask alignment apparatus according to the first or second aspect, wherein
Since the array is divided into a plurality of parts and a selective lighting circuit for controlling the lighting of each divided LED array group is added, it is possible to operate with minimum power consumption by lighting according to the alignment mark position of the wafer. It is also possible to display a guide for a wafer set by creating a specific light emitting pattern.

According to a fourth aspect of the present invention, there is provided a mask alignment apparatus according to the first or third aspect, wherein
Since the array is arranged in a substantially cross shape on the wafer mounting surface of the wafer chuck, the light emission of the LED array arranged in a substantially cross shape functions as a guide when mounting the wafer on the wafer chuck, making it extremely efficient and accurate The wafer can be mounted on a wafer chuck.

According to a fifth aspect of the present invention, in the mask alignment device according to the first to fourth aspects, a blinking circuit for controlling blinking of the LED array is added, so that the visibility is improved and the wafer can be more precisely formed. It can be mounted on a wafer chuck.

According to a sixth aspect of the present invention, in the mask alignment apparatus according to the first to fifth aspects, the emission wavelength range of the LED array is in the range of 570 to 610 nm, and white light is used as the light source. This eliminates the need for a filter for cutting short wavelengths.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a mask alignment apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention.

FIG. 3 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention.

FIG. 4 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention.

FIG. 5 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention.

FIG. 6 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention.

FIG. 7 is a schematic view showing a mask alignment apparatus according to another embodiment of the present invention.

FIG. 8 is a schematic diagram showing a mask alignment apparatus according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer chuck 2 Wafer suction hole 3 Transparent thin plate 4 LED array 5 Conductor wire 6 External power supply 7 Selective lighting circuit 8 Flashing circuit 9 Light emitting surface 10 Optical fiber 11 Filter 12 Halogen bulb

Claims (6)

[Claims] 1. A mask alignment device for aligning a wafer, comprising: a wafer chuck for mounting a wafer; a suction unit for suctioning the wafer mounted on the wafer chuck; A mask alignment apparatus comprising: an LED array arranged to emit light from the back side of a wafer mounted on a chuck; and a power supply connected to the LED array via a conductive wire. 2. The mask alignment apparatus according to claim 1, wherein an LED array is arranged on substantially the entire surface of the wafer chuck on which the wafer is mounted. 3. The LED array according to claim 1, wherein the LED array is divided into a plurality of LED arrays, and a selective lighting circuit for performing lighting control is added to each of the divided LED array groups.
The mask alignment apparatus according to the above. 4. The mask alignment apparatus according to claim 1, wherein said LED array is arranged in a substantially cross shape on a wafer mounting surface of said wafer chuck. 5. A blinking circuit for controlling blinking of said LED array is added.
The mask alignment apparatus according to the above. 6. The light-emitting wavelength range of the LED array is 5
The mask alignment apparatus according to claim 1, wherein the distance is in a range of 70 to 610 nm.