JP3230218B2 - Blind equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for manufacturing a semiconductor device by transferring a mask pattern onto a wafer surface, and a blind apparatus capable of exposing an arbitrary chip area by partially blocking exposure light. It is about.

[0002]

2. Description of the Related Art In general, a blind device used in an exposure apparatus is used to limit exposure light having a large area to light according to the size of a chip area. The main components are four rectangular blinds that move forward and backward, and a horizontal movement positioning setting mechanism system that drives each of the four rectangular blinds to position accurately at an accurate setting position surrounding an arbitrary chip area. I have.

(Conventional Example 1) A conventional blind device will be described with reference to the drawings. 3 and 4 show a prior art disclosed in Japanese Patent Application Laid-Open No. Hei 3-11613 by the present applicant. FIG. 3 is a plan view for explaining the concept of a positioning operation by a conventional blind device. 4 is the same front view.

In the figure, α is a blind device, D is a chip area, D 'is a masking area, L is exposure light, L' is alignment light, and W1 to W3 are wafer alignment marks. 1 is an X-ray mask, 2a to 2d are blinds, 3a to
3d is a horizontal movement positioning setting mechanism system, 4 is a mask stage, 5 is an X-ray absorber, 6 is a wafer stage, and 7 is a wafer.

In FIGS. 3 and 4, the blind device α
Above the mask stage 4, the chip area D
And four rectangular blinds 2a to 2d that horizontally move so as to surround the DC motor and a rotary encoder connected to a drive shaft and a rotary encoder that vertically and horizontally moves the respective blinds 2a to 2d and sets the position at an accurate position. Horizontal positioning mechanism 3a to 3d (3
a only shown).

The blinds 2a to 2d are a mask stage 4.
, And the X-ray mask 1 is provided near the mask stage 4. X on the bottom surface of X-ray mask 1
The line absorber 5 is uniformly applied, and a mask pattern is formed. Further, below the X-ray mask 1, a wafer stage 6 and a wafer 7 mounted on the wafer stage 6 are arranged.
Is arranged.

[0007] The blinds 2a to 2d shown in FIG.
Are arranged so as to form a square shape shown by oblique lines in the figure, and are accurately horizontally moved to a predetermined position by horizontal movement positioning setting mechanism systems 3a to 3d (only 3a is shown) in which a rotary encoder is connected to a drive shaft. In addition, the exposure light L outside the chip area D is shielded.

Thus, when the blinds 2a to 2d are not present, double exposure and quadruple exposure at corners caused by the leakage of the exposure light L through the absorber 5 to the adjacent chip area D are prevented. be able to.

The blinds 2a to 2d are made of a metal such as aluminum for shielding the exposure light L.
Reference alignment light L ′ (usually visible light or He-Ne) for aligning the X-ray mask 1 and the wafer 7.
A (helium-neon) laser is used. ) Is not transmitted.

[0010] Therefore, after performing alignment work of a predetermined procedure described later and pre-positioning and holding the wafer 7 at a predetermined position, the exposure work is performed by irradiating the exposure light L from above the blinds 2a to 2d.

(Conventional example 2) As another conventional example, the blind in the first conventional example is configured to block exposure light L,
Patent application “Blind device” (Japanese Patent Application No. Hei 1 (1999)) filed by the applicant of the present invention, using a material that transmits the alignment light L ′.
No. 144221 / JP-A-3-11613). In FIGS. 3 and 4, α 'is a blind device of the conventional example, and 2a' to 2d 'are the blinds.

The blind apparatus α 'of the present prior art differs from the blinds 2a to 2d of the first conventional example in that the blinds 2a' to 2d are made of a material that blocks the exposure light L and transmits the alignment light L '. , The alignment work and the exposure work are performed simultaneously, the wafer alignment marks W1 to W3 are always detected and the blinds 2a 'to 2
It was possible to control the position of d '.

As a material of the blinds 2a 'to 2d', a quartz glass or the like which transmits the alignment light L 'is used to constitute an optical filter having a selective transmittance to a light wavelength.

By disposing the blinds 2a 'to 2d' so as to cover the wafer alignment marks W1 to W3 arranged on the scribe lines on the XY axes, the mask alignment marks (not shown) on the X-ray mask 1 Since the transfer of the mask alignment mark to the surface of the wafer 7 by L can be prevented, the mask alignment mark can also be arranged on the adjacent chip region D across the scribe line.

The positioning operation is performed by irradiating the alignment light L 'onto the wafer 7 and setting the wafer alignment marks W1 to W
3 and drives the horizontal movement positioning setting mechanism systems 3a to 3d to perform guidance to a required position while performing feedback control.

[0016]

However, the first aspect
In the conventional example, the X-ray mask 1 for aligning the X-ray mask 1 with the wafer 7 and the wafer alignment marks W1 to W3 are used.
Is the periphery of the chip area D outside at least two sides of the rectangle that determines the chip area D, for example, a masking area D '.
Often placed. For this reason, the X-ray mask 1 and the wafer 7 during the exposure operation are aligned with each other by the close X-ray mask.
When an exposure apparatus using the line mask 1 and the wafer alignment marks W1 to W3 is used, the exposure light L is applied to the mask alignment marks M1 to M3 by exposure.

Therefore, when wafer processing such as etching is performed, the mask alignment marks M1 to M3 are
When the resist transferred onto the wafer 7 and applied to the wafer 7 is a positive type, the resist is removed corresponding to the shape of the mask alignment marks M1 to M3, and when the resist is negative, the resist remains. Step 7 occurs on the surface. For this reason, in the subsequent processes, uneven coating of the resist and deterioration of the shape of the wafer alignment marks W1 to W3 are caused.

In the first conventional example, the blind 2
When the X-ray mask 1 and the wafer 7 are aligned without masking by a to 2d, and the position of the X-ray mask 1 is read and held by a position detection system such as a rotary encoder connected to the drive system of the mask stage 4. At the same time, after the position of the wafer 7 is detected and held by a laser interferometer (not shown), the blinds 2a to 2d are driven by the horizontal movement positioning setting mechanism systems 3a to 3d, respectively, and moved to predetermined positions to perform exposure. It had been.

However, when the blinds 2a to 2d cover a part of the mask pattern formed on the X-ray mask 1 and perform exposure, the blinds 2a to 2d also shield the alignment light L '. Since the alignment marks W1 to W3 cannot be detected, the X-ray mask 1 and the wafer 7
Cannot be directly aligned, so that it is impossible to perform an alignment operation by a servo following control operation simultaneously with an exposure operation.

Therefore, when the present invention is applied to an X-ray exposure apparatus requiring an exposure time of several minutes to about one hour, the X-ray mask 1, the mask stage 4, and the wafer stage 6 are distorted due to thermal deformation or the like. The relative position between the wafer 1 and the wafer 7 was out of order, resulting in a decrease in the positioning accuracy.

When the blind apparatus α 'of the second conventional example is used, the blinds 2a' to 2d 'advance to the positions covering the mask alignment marks M1 to M3. The masking region D ', which is incompletely shaded at the periphery and is covered by the blinds 2a' to 2d ', penetrates and expands, and the chip region D that can be exposed by one operation is substantially reduced to the exposure leakage region E. This has the disadvantage that the update mark of the wafer 7 and other mask patterns cannot be formed in the masking area D '.

As a result, the mask array mark M1
In order for M3 to go out of the exposure leakage region E exhibiting incomplete shading, the exposure area of the chip region D has to be substantially reduced, which may hinder the circuit design, resulting in a poor yield. Here, an object of the present invention is to provide a blind device that does not reduce the exposure area, does not cause transfer of a mask alignment mark, and can perform an alignment operation even during an exposure operation.

[0023]

The above object can be attained by the present invention employing the following novel characteristic constitution means. That is, a feature of the present invention is that the exposure light is shielded, and the alignment light used for aligning the mask and the wafer is formed of a selective light transmitting material that transmits,
A plurality of blinds for forming a light-shielding convex portion of an arbitrary shape having an area as small as possible and sufficient to completely block exposure light with respect to a wafer alignment mark formed on a wafer surface, and surrounding the chip region of the wafer; A blind device comprising: a horizontal movement positioning setting mechanism system for driving each of a plurality of blinds so as to be positioned and movable in a plane.

[0024]

According to the present invention, by taking the above measures, the exposure light L irradiated to the periphery of the mask alignment marks M1 to M3 is completely shielded, so that the mask alignment marks M1 to M3 reach the wafer 7 surface. No unnecessary transfer occurs.

That is, since the light-blocking projections are formed on the blind, the portions of the mask alignment marks M1 to M3 do not deviate from the exposure leakage region E and do not decrease the substantial area of the chip region D.

Further, since the projection forming blind can be moved accurately to a position circumscribing the chip region D, the wafer alignment marks W1 to W3 can be moved to any position, shape and size outside the exposure leakage region E. It becomes possible to arrange it.

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
FIG. 2 is a plan view illustrating the use state of the blind device of the present embodiment, and FIG. 2 is a front view of the same.

In the figure, α ″ is the blind device of the present embodiment,
M1 to M3 are mask alignment marks, W1 'to W
3 ′ is a wafer alignment mark for positioning the next exposure layer, 8a to 8d are blinds, 9a to 9c are light-shielding convex portions,
10a to 10d are horizontal movement positioning setting mechanism systems, 11 is X
Line mask, 12 is a silicon substrate, 13 is a membrane, 1
Reference numeral 4 denotes an X-ray absorber, and reference numeral 15 denotes a mount. The same members as those of the conventional example are denoted by the same reference numerals.

The blind device α ″ of the present embodiment shown in FIG.
Are blinds 8a to 8d which form light-shielding convex portions 9a to 9c and have a selective transmittance with respect to light wavelengths, and horizontal movement positioning setting mechanism systems 10a to 10d which enable the blinds 8a to 8d to be freely movable in a plane. It is composed of

The blinds 8a to 8d are a mask stage 4.
And the X-ray mask 11 is provided near the lower side of the mask stage 4, respectively, and has a small refractive index and a small thickness in order to minimize a change in phase due to transmission of the alignment light L '. It is composed of a transparent material.

The X-ray mask 11 comprises: a silicon substrate 12;
The membrane 13 formed on the lower surface of the silicon substrate 12
An X-ray absorber 14 uniformly coated on the membrane 13 to form a masking pattern; and a mount 15 for attaching the silicon substrate 12 to the mask stage 4.
Consists of

The exposure light L is applied over a wide range from above the blinds 8a to 8d. Convex forming blinds 8a to 8c
Are formed with light-shielding convex portions 9a to 9c corresponding to the sizes of the mask alignment marks M1 to M3 and the wafer alignment marks W1 to W3.

The blinds 8a to 8d are arranged so as to surround the chip area D from four sides to a square, and two DC servos whose driving directions to which rotary encoders (not shown) are respectively connected are set so that the driving directions are perpendicular to each other in a horizontal plane. It is accurately moved to a predetermined position by a horizontal movement positioning setting mechanism system 10a to 10d which can be moved in a plane direction driven by a motor or the like, and the chip area D (substantially the exposure leakage area E)
The external exposure light L is shielded.

The projection-forming blinds 8a to 8c are limited to only the mask alignment marks M1 to M3 so as to be out of the exposure omission area E.
c, the portions of the chip area D that are not irradiated with the exposure light L are the light-shielding projections 9a to 9c.
And the other chip area D is exposed to the maximum.

Thus, the projection forming blinds 8a to 8c
Does not exist, the mask alignment marks M1 to M1
The problem that M3 is transferred onto the wafer 7 is avoided, and at the same time, since the projection forming blinds 8a to 8c sufficiently transmit the alignment light L ', the wafer alignment marks W1 to W3 are detected during the exposure operation. Alignment work can be performed simultaneously.

In order to perform the alignment operation at the same time during the exposure operation, the alignment light L 'is applied to the projection forming blind 8a.
~ 8c must be transmitted. For this reason, as the projection forming blinds 8a to 8c, a transparent material such as a glass plate (quartz, Pyrex glass) or a transparent plastic plate which is not deteriorated or deteriorated by the exposure light L or the alignment light L 'as in the second conventional example. The optical filter constituted by is used.

As the optical filter, a g-line (436 nm) or an i-line (360 nm) as an exposure light L or an excimer laser (<300 nm) is shielded, and a He-Ne laser (632) as an alignment light L ′ is used. .8n
m) or an orange filter, a yellow filter, or a UV filter having a transmission distribution transmitting visible light (400 nm to 760 nm).

Further, the wafer alignment marks W1 to W1
Since the peripheral region of W3 can be exposed, the wafer alignment marks W1 'to W3' necessary for positioning the next exposure layer can be simultaneously formed on the surface of the wafer 7.

At the time of forming the next exposure layer, the alignment light L ′ is irradiated to irradiate the next wafer alignment mark W
The positions of 1 'to W3' are detected, and the projection forming blind 8a
By moving the horizontal movement positioning setting mechanism systems 10a to 10d to the wafer alignment marks W1 'to W3', without reducing the area of the chip region D. It is possible to continue the exposure.

In this embodiment, such a specific embodiment is provided, and the mask alignment marks M1 to M3 are not applied to the entire blinds 2a 'to 2d' in the second conventional example but to the mask alignment marks M1 to M3. In order to limit the exposure light L to an area as small as possible necessary to completely shield the exposure light L, the projections 8a to 8c are formed with light-shielding projections 9a to 9c. The horizontal movement positioning and setting mechanism 10a to 10d that can move in the vertical and horizontal directions along the peripheral edge of the chip area D.
Thus, a configuration of an exposure apparatus in which the mask alignment marks M1 to M3 are not transferred onto the wafer 7 without substantially reducing or enlarging the irradiation area of the exposure device is realized.

Further, the mask alignment marks M1 to M1
Even in an alignment method in which M3 and wafer alignment marks W1 to W3 are superimposed on each other and aligned, the mask alignment marks M1 to M3 are not transferred onto wafer alignment marks W1 to W3, so that the shapes of wafer alignment marks W1 to W3 are changed. Is stored, and the wafer alignment marks W1 to W3 can be used as they are for alignment work of the next exposure layer.

In the present embodiment, the projection forming blinds 8a to 8a
Although the light-shielding convex portions 9a to 9c are formed on the portion c, the shape thereof is not limited as long as it has a sufficient area for completely shielding the exposure light from the wafer alignment marks W1 'to W3'. The area ratio in the chip region D can be reduced by reducing the area as much as possible.

Further, the horizontal movement positioning setting mechanism system 10a
Although an example in which a DC servomotor in which a rotary encoder is connected to a drive shaft is adopted as 10 to 10d, an arbitrary DC servomotor with a linear encoder, a pulse motor, or the like may be used instead as long as arbitrary movement in a plane is possible. Can be selected.

[0044]

As described above, according to the present invention, since the mask alignment mark is not transferred to the wafer surface by providing the blind having the selective transmittance to the light wavelength, the mask alignment mark is not transferred to the wafer surface in the subsequent wafer processing process. It prevents generation of steps due to the resist and deterioration of the shape of the wafer alignment mark, thereby enabling high-quality semiconductor chips to be manufactured.

Further, since the mask alignment mark is limited so as to completely shield the exposure light with the minimum area of only the blind light shielding convex portion, it is possible to make the most of the area of the chip region. Furthermore, since the wafer alignment mark can be formed so as to be included in the chip area,
The distance between adjacent chip regions on the wafer surface can be minimized, the number of chips obtained from one wafer increases, and the production efficiency can be improved.

During the exposure operation, the alignment operation can be performed simultaneously by the servo follow-up control operation, and the alignment accuracy between the mask and the wafer does not deteriorate even in the long-time exposure operation using X-rays as the exposure light. , Enabling highly accurate pattern formation.

When moving to the next exposure layer, only the light-shielding projections of the projection-forming blinds are moved linearly, so that it is possible to respond quickly and easily, and the exposing work is excellent in simplicity and simplicity.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a use state of a blind device according to an embodiment of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view illustrating a use state of a conventional blind device.

FIG. 4 is a front view of the same.

[Explanation of symbols]

.alpha., .alpha. ', .alpha. "Blind device D ... Chip region D' ... Masking region E ... Exposure leakage region L ... Exposure light L '... Alignment light M1 to M3 ... Mask alignment marks W1 to W3, W1' to W3 '... Wafer alignment mark 1 ... Blind device 2a-2d, 2a'-2d '... Blind 3a-3d ... Horizontal movement positioning setting mechanism system 4 ... Mask stage 5 ... X-ray absorber 6 ... Wafer stage 7 ... Wafer 8a-8d ... Blind 9a to 9c: Light-shielding projections 10a to 10d: Horizontal movement positioning setting mechanism system 11: X-ray mask 12: Silicon substrate 13: Membrane 14: X-ray absorber 15: Mount

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanori Suzuki 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-3-11613 (JP, A) JP-A Heisei 4-15907 (JP, A) JP-A-52-28874 (JP, A) JP-A-5-36589 (JP, A) JP-A-5-21320 (JP, A) JP-A 64-71123 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 9/00

Claims (1)

(57) [Claims] An exposure light is shielded, and an alignment light used for aligning a mask and a wafer is made of a selectively transmissive material that passes therethrough. The exposure light is completely shielded from a wafer alignment mark formed on the wafer surface. A plurality of blinds forming a light-shielding projection having an area as small as possible and having an area as small as possible and surrounding the chip area of the wafer; and a horizontal movement for driving each of the plurality of blinds in a plane so as to be movable. A blind device comprising a positioning setting mechanism system.