JP2002217079A - Aligner and spacer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expose an object having an arbitrary thickness with good resolution performance without replacing the supporting part. SOLUTION: The aligner comprises a light source 11, a supporting part 13 for holding an object 30 to be exposed at a specified position, and a spacer 20 for spacing apart the object 30 and the supporting part 13. The spacer 20 has recesses 23 and 24 for sucking the object 30 on the surface or rear and preferably comprises a planar member having a suction through hole 27 extending to that recess from the other surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an exposure apparatus suitable for forming a fine pattern by photolithography and a spacer used in the exposure apparatus.

[0002]

2. Description of the Related Art In manufacturing a semiconductor device having a fine circuit pattern, a patterning technique called photolithography is often used. In photolithography, the photosensitive resin composition film is cured by irradiating light through a mask, developed, and the original pattern of the circuit pattern drawn on the mask is transferred to the resin film, which is used as a resist. This is a technique of etching and patterning a metal film or the like under a resin film.

In this photolithography, if the exposure surface deviates from the focal plane, a uniform resolution cannot be obtained, and the image is blurred. Therefore, in order to transfer a fine pattern with high accuracy, it is necessary to precisely arrange the surface to be exposed on the focal plane (or within the range of the depth of focus).

[0004]

An exposure apparatus has a support for holding an object to be exposed. This support section is arranged in the X direction (horizontal direction) to dispose the exposure target at a predetermined position.
It often has a drive mechanism for moving in the Y direction (depth direction) and the Z direction (height direction).

However, in order to form a fine pattern, it is necessary to precisely align the exposure surface, and there is a limit to the distance traveled by the support. In particular, movement in the Z direction
Usually, only about ± 0.3 mm can be accurately moved.

Therefore, in order to expose an exposure object having various thicknesses, the exposure surface must be accurately arranged on the focal plane (ie, the surface on which the exposure object is to be placed is at an appropriate position). 2), the stage on which the exposure target of the support portion is placed must be replaced.

However, since the position of the stage of the supporting portion is required to be high, it is very troublesome to replace the stage, thereby deteriorating the working efficiency. In addition, since high precision flatness, horizontality, and movement accuracy are required, the support portion is an expensive member, and it is very costly to manufacture the support portion every time an exposure target having a different thickness is exposed. Was high.

Therefore, the present invention provides an exposure apparatus capable of exposing an exposure object having an arbitrary thickness with good resolution without exchanging a supporting portion (stage), and a spacer used in the apparatus. The purpose is to:

[0009]

In order to achieve the above object, the present invention provides a light source and a support for holding an object to be exposed at a predetermined position, and separates the support from the object to be exposed. Exposure apparatus further provided with a spacer for the same.

According to the present invention, as a spacer used in the exposure apparatus, there is provided a spacer for separating an object to be exposed and a supporting portion for holding the object to be exposed at a predetermined position at a predetermined interval. Is done.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The spacer of the present invention has a concave portion on one surface (hereinafter, referred to as a first surface), and penetrates the concave portion from the other surface (hereinafter, referred to as a second surface). It is desirable that it is a plate-shaped member having a through hole. With this configuration, when using an exposure apparatus having a support unit (suction holder) having a mechanism for sucking an exposure target by suction,
The suction port of the support is aligned with the opening of the through hole of the spacer, the spacer is placed on the support with the second surface facing the support, and the spacer is placed on the first surface of the spacer. By mounting the exposure target so as to cover the recess, the exposure target and the spacer can be fixed by suction.

In this case, the recesses may be of any shape as long as they can communicate with the through-holes and maintain a reduced pressure state when the exposure object is placed and sucked. It is preferable to use a plurality of communicating concentric grooves, because it is easy to form. The grooves can be reliably sucked without deforming the exposure target and can be easily formed. Therefore, the pitch is 10 to 15 mm, the depth is 50 μm or more (more preferably, 0.1 mm or more), and the width is 0.8 to 1 mm.
It is preferable that The concave portion and the through hole for suction can be formed by, for example, sandblasting.

The material of the spacer is not particularly limited as long as it can support the object to be exposed in a predetermined position. A material having hardness enough to maintain a reduced pressure state is used. For example, metal, ceramic, glass, resin, and the like are suitable for the present invention. Among them, quartz glass, in particular, is capable of forming a plate-like member having a uniform thickness and a high plane accuracy with high precision, is easy to process the concave portion for suction and the through hole, and is hardly deformed by decompression. It is preferable because it does not exist.

The thickness of the spacer is not particularly limited as long as the exposure target can be supported at a predetermined position. The focal position of the exposure light, the distance between the focal position and the support, the thickness of the support, and the like. It can be appropriately determined according to the movable range, the thickness of the exposure target, and the depth of the surface to be exposed. In the present invention, as the spacer, for example, a thickness of 0.4 to 7.0 mm
Can be used.

It is desirable to provide a guide on the first surface of the spacer for aligning an exposure object placed thereon. This guide is, for example, the XY of the first surface.
It can be provided by attaching an L-shaped thin plate (or two or more strip-shaped thin plates) for defining the X-direction position and the Y-direction position on a plane to the first surface.

The exposure apparatus of the present invention includes a light source and a support for holding an object to be exposed at a predetermined position, and includes the above-described spacer of the present invention between the light source and the support. It is desirable that the spacer is used by being placed on the support portion, and is easily detachable.

The exposure apparatus of the present invention is suitably used for pattern formation by general photolithography, such as patterning of an etching resist made of metal, resin, glass or the like, or for forming an insulating film on a semiconductor wafer. For example, when forming a chromium mask or forming a low-reflection film using chromium oxide, when patterning an etching resist of chromium or chromium oxide, or when manufacturing a diffraction grating,
The exposure apparatus of the present invention can be used for patterning an etching resist of glass.

The light source is not particularly limited as long as it emits light having a wavelength determined according to the object to be exposed. Mercury lamps, excimer lasers (KrF, A
An ordinary light source such as rF, F _2, or synchrotron radiation can be used. The wavelength of the exposure light is not particularly limited, and radiation (X-rays, electron beams, etc.), ultraviolet rays (g-rays, h-rays, i-rays, extreme ultraviolet rays, etc.), visible light, etc. are appropriately selected and used. Can be. Note that the exposure apparatus of the present invention may further include an optical system for uniformly irradiating the exposure light with a predetermined range.

The support section has a stage for arranging the exposure target at a predetermined position, and moves the exposure target in the X direction (lateral direction), the Y direction (depth direction), and the Z direction (height direction). And a driving mechanism for causing the driving mechanism. The drive mechanism may have a function of adjusting the inclination. Further, a temperature control mechanism may be provided in order to prevent deformation or cracks due to a change in temperature. Further, a sensor for detecting the height and the inclination may be provided on the support portion.

It is desirable that the support section has a suction mechanism for sucking and fixing the object to be exposed. As the suction mechanism, for example, an air flow path having an opening (suction port) may be provided on the surface of the support section on which the spacer is placed.
In this case, it is desirable that the exposure apparatus is provided with a means for reducing the pressure of the air flow path.

It is preferable that a positioning mechanism for defining the X direction and the Y direction of the spacer is provided on the surface of the supporting portion on which the spacer is placed. As the positioning mechanism, for example, an elastic body (such as a leaf spring) that presses a guide provided on the spacer to determine the position can be used. Further, a guide (an L-shaped thin plate or two or more strip-shaped thin plates, etc.) for respectively defining the position in the X direction and the position in the Y direction may be provided on the surface of the support portion on which the spacer is placed.

Further, the exposure apparatus of the present invention is provided with a mask driving mechanism for moving a photomask (reticle), a mechanism for exchanging the mask, a mechanism for detecting foreign matter on the mask surface, and the like, as required. You may.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

A. Exposure Apparatus The exposure apparatus 10 used in this embodiment is, as shown in FIG.
Light source 11, optical system 12, spacer 20, supporting portion 1
3 and decompression means (vacuum pump 14 and suction pipe 15)
And a control device 16 for controlling the operations of the light source 11, the support unit 13, and the vacuum pump 14.

In this embodiment, a high-pressure ultraviolet lamp is used as the light source 11. The light source 11 is controlled by the control device 16. The optical system 12 transmits the exposure light from the light source 11 to the optical axis 17.
And a collimator lens or the like for uniformly irradiating a predetermined range (exposure region) centered at the center. In the exposure apparatus of this embodiment, the distance (working distance (WD)) from the optical system 12 to the focal plane is 19 mm.
The depth of focus is about 0.87 μm.

The support section 13 has a stage on which the exposure target 30 and the spacer 20 are mounted, and a surface on which the exposure target 30 and the spacer 20 are mounted (hereinafter, simply referred to as a mounting surface). , X direction (lateral direction), Y direction (depth direction) and Z direction (height direction)
A drive mechanism for correcting the inclination is further provided. The mounting surface of the support portion 13 is ± 10 in each of the X direction and the Y direction.
It can move with high precision in the range of ± 0.3 mm in the cm and Z directions. This drive mechanism is controlled by the control device 16.

The stage of the support section 13 has an air flow path 18 having an opening (suction port) 19 on the mounting surface.
The air flow path 18 is connected to the vacuum pump 14 by a pipe 15, and the pressure is reduced by operating the vacuum pump 14. The operation of the vacuum pump 14 is controlled by the control device 16.

Further, the exposure apparatus 10 of this embodiment includes a mask holder 32 for holding a photomask 31. The mask holder has a drive mechanism for moving the mask, and the operation of the drive mechanism is controlled by the control device 16.

B. Spacer The spacer 20 used in this embodiment is shown in FIG. 2A, and a cross-sectional view taken along the line AA ′ in FIG. 2A is shown in FIG. In addition, the scale of each part was arbitrarily changed in order to make the figure easy to see.

In the exposure apparatus 10 of this embodiment, spacers 20 having various thicknesses are prepared. In the present embodiment, a spacer having a thickness of 5.9 mm is determined based on the working distance of the exposure apparatus 10, the thickness of the wafer 30, and the position of the mounting surface of the support unit 13 so that the focal plane is the surface of the wafer 30. 20 was used.

The spacer 20 used in this embodiment is a quartz glass plate 21 of 152.4 mm in length and width and 5.9 mm in thickness.
And a guide 22 attached to the surface of the glass plate 21 with an epoxy resin adhesive. The guide 22 has a width of 15 mm in the vertical direction, a width of 10 mm in the horizontal direction, an L-shape having a length of 10 cm in each of length and width, and is made of a stainless steel thin plate having a thickness of 1 mm.

On the surface of the quartz glass plate 21, three concentric grooves 23 (with a depth of 0.1 m) formed at intervals of 10 mm as suction concave portions for sucking an object to be exposed.
m, width 0.8 mm), and a linear groove 24 communicating with these circumferential grooves 23. Of the three circumferential grooves 23, the outer groove 23 has a diameter of about 9 cm.

The quartz glass plate 21 is provided with a suction through hole 27 (0.5 mm in diameter) for sucking the air in the groove 23 and sucking the exposure object. Through hole 27
Has openings 25 and 26 at the bottom of the groove 23 and at the back of the glass plate 21, respectively. In addition, in FIG.
Although only one (and its opening) 7 is illustrated, the present invention is not limited to this, and can be provided as appropriate according to the number and position of the suction ports 19 of the support 13.

C. Exposure Processing In the present embodiment, the above-described exposure apparatus 10 was used for the exposure processing in the semiconductor device manufacturing process. The outline of the manufacturing process of the semiconductor device in the present embodiment is as follows.

First, a metal or metal oxide is formed on the surface of the silicon wafer 30 by sputtering, and a photosensitive resin composition film is formed on the surface of the metal (or metal oxide) film. The composition film was exposed through a mask 31 (FIG. 1) having a predetermined pattern using the exposure apparatus 10 and developed to obtain a resist having a predetermined pattern. Subsequently, the exposed portions of the metal (or metal oxide) film that were not covered with the resist were removed by etching to form a metal (or metal oxide) pattern. By repeating the above process a plurality of times, a semiconductor wafer 30 on which a predetermined pattern was laminated was obtained. The semiconductor wafer 30 was diced into semiconductor chips, which were die-bonded on a lead frame, wire-bonded, and then resin-sealed to obtain semiconductor devices.

Since the steps other than the exposure step in the above manufacturing steps are the same as the conventional steps, the exposure step will be described here.

First, the spacer 2 is placed on the mounting surface of the support 13.
0 is a suction port 19 provided on the stage of the support portion 13.
And the spacer 20 was placed so that the position of the through hole 27 of the spacer 20 and the opening 26 on the back side were matched. Next, this spacer 2
The semiconductor wafer 30 to be exposed was placed on the surface of the substrate 0 so as to cover the concave portions for suction (grooves 23 and 24). The semiconductor wafer 30 has a disk shape with a diameter of 101.6 mm and a thickness of 0.4 mm, and a photosensitive resin composition is previously formed on a predetermined region of the surface.

Subsequently, the controller 16 controls the vacuum pump 1
The spacer 20 and the wafer 30 were adsorbed on the support portion 13 by driving the nozzle 4 to reduce the pressure in the air flow path 18 and the suction through hole 27.

Next, the control device 16 operates the drive mechanism of the support portion 13 to adjust the position of the wafer 30 so that a predetermined portion is arranged in the exposure area, and the control device 16 operates the drive mechanism of the mask holder. The surface of the wafer 30 was irradiated with ultraviolet rays via the mask 31 arranged at a predetermined position.

This exposure process is performed by using the wafer 30 and the mask 31
Are sequentially moved to other parts on the wafer by the step-and-scan method.
Exposure was performed on all of the 0 predetermined portions. Then, the wafer 30
Was removed from the spacer 20 and developed. As a result, the mask pattern was accurately transferred, and no image blur was observed even at the pattern edge.

Although the exposure apparatus 10 of the present embodiment employs the step-and-scan method as described above, the present invention is not limited to this, and employs another method such as a step-and-repeat method. It may be.

[0042]

According to the present invention, by appropriately selecting the thickness of the spacer, an exposure object having an arbitrary thickness can be exposed with good resolution without exchanging the support portion.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an exposure apparatus used in an embodiment.

FIG. 2 is a perspective view and a cross-sectional view of a spacer used in an example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus, 11 ... Light source, 12 ... Optical system, 13 ... Support part, 14 ... Vacuum pump, 15 ... Suction piping, 16 ... Control device, 17 ... Optical axis, 18 ... Air flow path, 19 ... Suction port, 2
0: spacer, 21: quartz glass plate, 22: guide, 2
3, 24 ... groove, 25 ... groove side opening of suction through hole, 26
... opening on the back side of the through hole for suction, 27 ... through hole for suction,
30 silicon wafer or semiconductor wafer (exposure target),
31 photomask (reticle), 32 mask holder.

Claims (3)

[Claims] 1. An exposure apparatus comprising a light source and a support for holding an object to be exposed at a predetermined position, comprising: a spacer for separating the object to be exposed from the support. apparatus. 2. A spacer for separating an object to be exposed and a supporting portion for holding the object to be exposed at a predetermined position at a predetermined interval. 3. The spacer according to claim 2, wherein the spacer is a plate-shaped member having a concave portion on one of the front and back surfaces and a through-hole penetrating the concave portion from the other surface.