JPH0869958A - Method and device for manufacturing x-ray mask - Google Patents

Abstract

PURPOSE: To realize the high precision, high resolution, low cost and wide exposure area by a method wherein one mask pattern is formed by arranging a plurality of original plates of patterns arrayed on a specific relative positions on a substrate using a scanning reduced exposure to be transferred. CONSTITUTION: A reticle 115 and X-ray mask 127 are scanned in Y axial direction at a scanning ratio of N: 1. In this scanning process, AA signals are transmitted in the timing when the light flux and the checking area of alignment checking systems 111, 112 enter into the areas of SAA(x) 73, 96, SAA(y) 71, 90. After further scanning process, AA signals are transmitted in the timing when SAA(x) 83, 100, SAA(y) 81, 98 enter into the pattern areas of said light flux, etc., repeatedly. Finally, after processing the slippage between the reticle 115 and the X-ray mask 127, the rotary stage 131 on X, Y stages 129 and XY surface is moved so as to make the precise mutual alignment between the reticle 115 and the X-ray mask 127.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray mask manufacturing method and apparatus used in X-ray lithography or the like using X-rays as exposure light.

[0002]

2. Description of the Related Art As semiconductor devices become highly integrated,
It is said that compatibility between resolution and exposure size is approaching the limit. For semiconductor devices of 256M DRAM, the exposure technology for resolving 0.25μm level is 1GDR
The semiconductor device of AM requires an exposure technique for resolving 0.15 μm level, and the X-ray exposure technique is regarded as promising.

In X-ray lithography using synchrotron radiation light or the like as exposure light, pattern transfer is usually performed by equal-magnification exposure. Therefore, the mask accuracy directly affects the transfer accuracy, and various studies have been actively conducted.

On the other hand, a method generally known as a method for producing an X-ray mask for equal-magnification transfer is to absorb by ion beam exposure or electron beam exposure and etching after laminating a membrane and an absorber on a substrate. A desired pattern (that is, a mask pattern) is formed on the body, and back etching is performed to hollow out the substrate in the X-ray exposure region before or after the pattern formation.

[0005]

In the above-mentioned ion beam exposure or electron beam exposure, the drawing range is usually a range that can be processed by electromagnetic deflection. Therefore, when a larger range is to be drawn, the range is divided into a plurality of fields. Field exposure is performed by repeating the drawing by moving the stage to the next field each time drawing of each field is completed. Therefore, the pattern placement accuracy (long dimension accuracy) is determined by the length measurement accuracy and the positioning stop accuracy in the stage moving mechanism during the field exposure. Therefore, even if the target pattern size in the exposure area becomes small, the pattern placement accuracy does not change.
6M (0.25 μm Line and Space)
And 1G (0.15 μm Line and Spac
In the mask writing of the generation e), the low pattern placement accuracy also causes a problem that the target overlay accuracy cannot be cleared when a semiconductor circuit is created. That is, if the mask is patterned by EB drawing, the cost becomes very high, or it is difficult to obtain the one with sufficient drawing accuracy. Furthermore, in order to realize the IC chip size and throughput of the 1G era, 30mm or 35m
An X-ray mask having a wide exposure size such as m 2 is required.

The present invention has been submitted in view of the above problems of the prior art, and provides a new method and apparatus for producing an X-ray mask which realizes high precision, high resolution, low cost, and wide exposure area. It is a thing.

[0007]

The inventor of the present invention has made earnest studies to solve the above problems and arrived at the present invention.

That is, according to the present invention, a mask is characterized in that a plurality of original plates are used to form one mask pattern by transferring the patterns of these original plates side by side in a predetermined positional relationship on a substrate by scanning reduction exposure. The method of manufacturing the mask, wherein each original plate is provided with a predetermined detection mark, and the pattern of each original plate is arranged in a predetermined positional relationship based on the detection of the detection mark. Is the way. A method for manufacturing a mask, wherein the mask is an X-ray mask, and the method for manufacturing a mask, wherein the exposure is performed by ultraviolet rays or light in a wavelength range of X-rays.

Further, means for transferring the pattern of the original plate onto the substrate by scanning reduction, means for detecting a predetermined detection mark of the original plate, and a plurality of original plate patterns in a predetermined positional relationship based on the detection of the detection mark. The present invention provides a method for manufacturing a mask, which has means for arranging them and transferring them to a substrate.

The present invention also provides a mask manufactured by any one of the above manufacturing methods.

Therefore, according to the present invention, an X-ray mask is manufactured by stacking an absorber on a membrane forming a mask, performing pattern exposure, and then etching the absorber to form a desired pattern. About how
When reducing projection light (including Deep UV) exposure or X-ray exposure is performed on the exposure pattern, the reducing projection optical system including a lens or a mirror has a conjugate relationship (or a partial conjugate relationship). The reticle and the exposed object to be the X-ray mask are scanned at a ratio of H: 1 to be printed and exposed.
In order to widen the printing area of the exposed object that will become the X-ray mask after replacing the reticle with another pattern,
The basic feature is to obtain an X-ray mask of a wide exposure area with high definition by connecting to an already exposed area, aligning and exposing again. At the time of this baking, in a region other than the so-called IC pattern area, a scribe line (a region where the device is cut into chips)
In order to prevent the excessive pattern from being burned too much, and to secure the pattern that performs the original alignment function required when using it as an X-ray mask, as many layers as necessary for the scribe area. It is one of the features. Further, a shift detection mark is provided so that the accuracy of connection (stitching) can be quantitatively evaluated in the pattern exposure when the X-ray mask is formed, and the measured value based on this pattern is used as the original X-ray mask. Highly accurate alignment is achieved by using it as a correction value for alignment when used as a mask, that is, for the alignment of the X-ray mask and the wafer to be exposed at that time.

Summarizing the above, the features of the present invention are to obtain a wide field X-ray mask.
A light (including deep UV) or X-ray reduction stepper scans the reticle and the X-ray mask, which is the object to be exposed and is the object of preparation. << Scan exposure >>. Further, in order to make it a wide field, the pattern is printed by connecting it on an X-ray mask which is an object to be exposed << stitching >>. At this time, the reticle should be replaced with another pattern if necessary, and then stitched. In some cases, the same pattern may be acceptable. At the time of stitching, the patterns to be connected are aligned with each other, or the alignment is realized with the feed accuracy of the STG on which the X-ray mask to be exposed is mounted. A sufficient area is secured in the so-called scribe line area of the obtained X-ray mask when it is used as a mask so that an alignment pattern or the like to be originally provided can be set. Therefore, when creating the X-ray mask, try to prevent unnecessary patterns from entering the scribe area. A pattern that allows quantitative evaluation of stitching (connection, connection) is provided, and the measured value from this pattern is used for correction during alignment when the mask is used as the original X-ray mask. It means that. As a result, a wide field, high resolution, high position accuracy, low cost, and X-ray mask for a wide exposure area are realized.

Hereinafter, the details will be described with reference to the drawings.

[0014]

EXAMPLES Next, examples of the present invention will be described separately for different cases. The cases are as follows. In both cases, an example of an optical stepper will be mainly described, but the same can be applied when an X-ray reduction imaging system is used. 1. When there is no scribe line between the A pattern and the B pattern (see FIG. 1), 1-1. When A pattern is exposed and developed and then a resist is applied and then B pattern is exposed and developed 1-1-1. When performing alignment between A pattern and B pattern (similar to alignment between layers) 1-1-2. When aligning with stage feed accuracy,
That is, when not relying on the AA pattern 1-2. When A pattern is exposed and B pattern is exposed and then developed 1-2-1. When aligning with stage feed accuracy,
That is, when not relying on the AA pattern 1-2-2. When alignment is performed between pattern A and pattern B (similar to alignment between layers). At this time, so-called latent image alignment is used.

2. When there are scribe lines in A pattern and B pattern Ashida, 2-1. When A pattern is exposed and developed, then a resist is applied and then B pattern is exposed and developed 2-1-1. When alignment is performed between the A pattern and the B pattern (similar to alignment between layers), 2-1-2. When aligning with stage feed accuracy, 2-2. When A pattern is exposed and B pattern is exposed and then developed 2-2-1. When aligning with stage feed accuracy.

2-2-2. When alignment is performed between the A pattern and the B pattern (similar to alignment between layers), so-called latent image alignment is used at this time. Specific examples will be sequentially described according to the above case classification.

Example 1 1-1-1. An example in this case will be described with reference to the drawings. 2 and 3 show the relationship between the arrangement of the patterns in the reticle 47 and the function when exposing the A pattern and the B pattern in this case in an easy-to-understand manner. That is, FIG. 2 shows an area where the reticle is exposed to light when the pattern A is printed and what kind of pattern exists there. As shown in FIG. 2, a pattern RAA 101, 102 for setting and aligning the reticle 47 at a predetermined position with respect to the exposure apparatus on the reticle for printing the A pattern, and completed as an X-ray mask. Pattern M / AA patterns 78, 80, 87 for positioning alignment with the X-ray exposure apparatus when used as an X-ray mask, and pattern W for alignment with a wafer when used as an X-ray mask・ AA patterns 76, 78, NEXT which is pre-baked on a wafer for alignment of the next layer when used as an X-ray mask ・ Layer patterns 77, 79, B pattern necessary for stitching when creating an X-ray mask Pre-exposure print to align to ensure the relationship Need stitching AA pattern SAA (x) 73 and SAA
(Y) 71 and S ・ AA (x) 83 and S ・ AA (y) 8
There is one. Here, x and y define the azimuth of the coordinates attached to the figure, where (x) means the X direction and (y) means the y direction. Further, on the reticle of FIG. 2, pattern A, pattern B
Patterns OL.A (x) 74, OL.A (y) 72, for detecting how much the connection alignment error causes printing after the patterns are adjacently connected and exposed.
An OL.A (x) 84 and an OL.A (y) 82 are provided. The characteristic of the pattern arrangement of FIG. 2 is that the W / AA pattern, the NEXT layer pattern, the S / AA pattern, and the OL / AO pattern are all X-ray masks, and when used as a mask, X Cutting between chips on a wafer when baked with a wire. The point is that it can be set in an area corresponding to a so-called scribe line. Also, M ・ A
If the pattern A is a pattern in which 75 and 80 are opposed to each other, it is better to talk to each other in order to improve the accuracy of mask alignment when used as an X-ray mask. The area indicated by A in the figure is a so-called IC circuit pattern area, and the area indicated by the diagonal lines blocks the exposure light, for example, Cr.
This is the area where the film is provided. The area where the reticle is exposed to light during scan exposure is shown as W × L.
And L need only satisfy the following conditions. Here, the scanning direction is the y direction. That is, W is the M.AA pattern 87, SAA (y) 71; OLA (y) 72, SA
A (x) 83; OL.A (x) 84, M.AA patterns 80 need to be exposed to light, so they must be covered. Also, L in the scanning direction is M
It is necessary to cover and expose the AA patterns 75 and 80. R / AA pattern 101 and R / AA pattern 102
Since it is a pattern for aligning the reticle 47 with respect to the exposure apparatus, it need not be exposed to the exposure light. W x L
The rough limit of the exposure area of
It can be provided by an aperture or slit on the illumination light source side. Further, L may be controlled by the feed amount of the reticle stage. Although FIG. 2 shows as if there is a B pattern, the actual reticle is a reticle in which the IC pattern is only the A pattern, and the necessary patterns described above are arranged in addition to this. By the way, when it is assumed that the exposure area of the finally completed X-ray mask is 40 mm × 40 mm, for example, W may be about 25 mm and L may be 45 mm to 50 mm.
Further, it is possible to make a small space in which Δx is about 1 mm or less and Δy is 100 μm or less.

Similar to the printing reticle for the A pattern shown in FIG. 2, the pattern arrangement for the reticle for printing the B pattern is shown in FIG. In FIG. 3, B indicates an IC circuit area of the B pattern, R-AA10.
Reference numeral 1,103 denotes a reticle alignment pattern for positioning this reticle with respect to the scanning exposure apparatus, and W
The AA patterns 89 and 94 are patterns for aligning the wafer with the X-ray mask after completion as an X-ray mask, and the NEXT / layer patterns 88 and 93 are alignment patterns for the next layer when printing on the wafer as an X-ray mask. Pattern to be printed on the wafer for
The AA pattern 92 is a mask alignment mark for aligning the mask with the X-ray exposure apparatus when used as an X-ray mask, S · AA (x) 96, 100, SA.
A (y) 90 and 96 are alignment patterns for connecting the A pattern and the B pattern and printing while maintaining the mutual relations accurately, OLB (x) 99, 95, OLB
(Y) 97 and 91 are detection marks for detecting the amount of error that results when the A pattern and the B pattern are connected and exposed, and FIG. Means the same. (X) and (y) mean the X direction and the y direction, respectively.

FIG. 4 shows the reticle for A pattern of FIG.
The arrangement of the pattern of the X-ray mask created while performing the stitching alignment with the scan exposure machine using the B pattern reticle of FIG. 3 is shown. In practice, an absorber such as Au is provided outside the position corresponding to the scribe area on the wafer to block X-rays.
Is omitted. The points on the pattern layout obtained as an X-ray mask can be reticle aligned to the scan exposure machine.
There is a reticle AA mark RAA. This should not be in the scan exposure area.

Mask A for enabling mask alignment to an X-ray exposure apparatus when used as an X-ray mask
There are A marks M and AA.

There are W / AA marks and NEXT / layer marks for aligning the X-ray mask and the wafer.

The stitching alignment patterns S.AA (x) and S.AA for utilizing the alignment function when the stitching connection of the patterns A and B is performed.
There is (y).

An OLA which is also called an overlay detection mark for detecting the stitching alignment error amount.
(X), OLB (x), OLA (y), OLB (y). At this time, OLA (x) and OLB (x) are detected as a pair, and OLA (y) and OLB (y) are detected as a set by another pair.

The outer frame of the A and B patterns in FIGS.
The area between the dotted lines corresponds to the scribe line area on the wafer. If the scan exposure machine performs 1 / N times reduction exposure, N times the size of the pattern on the X-ray mask becomes the reticle size.

Here, how to use the pattern of the pair of overlay detection marks OLA (x), OLB (x) and the pair of OLA (y), OLB (y) for detecting the alignment error amount. Describe.

The overlay error detection method disclosed in JP-A-4-212002 and JP-A-5-87530, which has been already submitted by the present applicant, is one of overlay detection methods.
Is one. This method is as shown in FIG.
The 1b diffraction grating pattern is used for the Nth exposure and the N + exposure, respectively.
The one that was baked to the first layer at the same time (wafer, etc.
In the case of the present invention, an X-ray mask is created, and a laser beam is applied to the patterns of 141a and 141b to cause the diffracted lights to interfere with each other (this is I ₁ ). the using I ₂₎ as a reference grating, for detecting the phase shift of I ₂ and I _1. At this time, the original laser light has a slightly different frequency (0.1 MHz
(-Several tens of MHz) If the two-frequency light is used, the above I ₁ , I ₂
Since the phase of the herrodyne light is obtained as the phase of the strength of the electric grating, the lock-in amplifier or the like provides high accuracy (with accuracy of about 1 mm) to 141a and 141a.
The phase shift Δx of the grating of b is obtained as the electrical phase shift. In FIG. 6, the grating pitch is, for example, 1 μm to 10 μm.
The value may be set in accordance with the wavelength of the laser light, the direction of the diffracted light, and the order in the order of μm. In addition to this, as it is commercialized by KLA (KLA 5011 system; product name)
There is also a method in which a simple pattern is exposed and baked at the same time, and the pattern is captured as an image and processed to detect an overlay error. FIG. 7 shows an example of the pattern. The pattern 142a is exposed simultaneously with the Nth layer, and the pattern 142b is exposed simultaneously with the N + 1th layer. FIG. 8 shows the principle of overlay error detection of the Nth and N + 1th layers. Captured with a vast image such as a microscope and a photodetector,
Find the edge profile of the pattern b. This time,
If the overlay deviation is dx

[0027]

[Equation 1]Required by. Where X_ol, X_or142a
Output value, X_il, X _irIs the output value of the edge of 142b
Means

As described above, the pattern of FIG. 6 or 7 may be a pattern of a pair of overlay detection marks OLA (x), OLB (x) and a pair of OLA (y), OLB (y). The pair pattern means that OLA (x) is, for example, 141a or 142a, and OLB (x) is 14
It means that it is 1b or 142b. OLA
It should be considered that (y) and OLB (y) are different only in the direction in the y-axis direction in FIG. 5, like OLA (x) and OLB (x).

Next, the configuration and function of the scan exposure apparatus capable of forming the mask shown in FIGS. 2, 3 and 4 will be described.

FIG. 5 shows an embodiment of the scan exposure configuration. The scan exposure apparatus shown in FIG. 5 requires the following functions.

(A) Reticle AA (Aligning the reticle 115 with the device of the scan exposure machine) (b) Stitching AA (c) Due to scan exposure, the conjugate relationship between the reticle 115 and the X-ray mask 127 is instantaneous. For this, a two-point focus is sufficient. Therefore, the exposed X-ray mask is dynamically tilted to perform focusing with high accuracy.

(D) Slit illumination for scanning In addition to this, the reticle is more effective if it is a phase shift mask in order to increase the resolution and the depth of focus.
The resolution and depth of focus can be further increased by using technologies such as modified illumination, which has been attracting attention recently. Although the phase shift cost cannot be ignored when chips are printed on a normal wafer, compared with the cost when originally patterning an X-ray mask by EB drawing, the scan exposure machine is the same one after another. With this method, which can mass-produce many sheets with a reticle,
The cost of a phase shift reticle is of little concern.

The above (a), (b), (c) and (d) will be described with reference to FIG.

Reference numerals 111 and 112 denote alignment detection systems for performing the reticle AA and stitching AA, and the reticle AA is provided for the alignment detection system on the apparatus side. 114 is a slit aperture, but reticle 1
Instead of placing the slit aperture immediately before 15, slit slit apertures may be provided on the light source side before and after the position substantially conjugate with the slit. Thirteen
0 is an illumination luminous flux. 118 is a reticle holder, 1
Reference numeral 16 is a reticle stage and 117 is a drive system thereof.
119 is a mirror, 120 is a lens system, 121 is a half mirror or a polarization beam splitter, 122 is a mirror, 1
23 is a lens system, 127 is an X-ray mask which is an object to be exposed,
128 is a tilt stage, 129 is an X, Y stage, 1
Reference numerals 24 and 124 are systems that perform focus detection so that the X-ray mask surface and the reticle 114 are in focus with respect to the mirror 119 to the lens system 123. If defocusing is performed based on the detected values, X-rays are generated by the tilt stage 128. The mask 127 is n.
Accurate focusing is performed by chilling on the z-plane or parallel planes. Reference numeral 126 is a control unit for driving the tilt stage 128 based on the result of the focus detection system 125 for that purpose. The reticle is illuminated in a slit aperture shape (the longitudinal direction of the slit is the y direction in FIG. 5), and the scan speed of the reticle 115 and the X-ray mask 127 is scanned N: 1 according to the reduction magnification of 1 / N. Focusing may be performed on a certain two points of the slit-shaped reticle effective portion. This is more effective when the surface to be exposed is slightly uneven, as compared with the surface focusing, that is, the three-point focusing in the batch exposure method. Accurate pit alignment with little error can be performed. In the focus detection system of 124 and 125, for example, 124 is a semiconductor laser or LED that moves two beams to an X-ray mask 127 which is an exposure target,
The focus can be detected by, for example, detecting with a PSD (position sensor) inside.
Since it is necessary to instantaneously focus two points between the reticle 115 and the X-ray mask 127, the X-ray mask 127 has an uneven surface corresponding to the movement of the scan stage 129, so that the X-Z mask 127 has an uneven surface. Tilt stage 1 in parallel direction
It is necessary to tilt at 28 to always focus.
In FIG. 5, 132 is a length measuring machine that measures the movement of the reticle stage, and 133 is a length measuring machine that measures the x and y movements of the X-ray mask 127. Next, an example of automatic alignment used for stitching AA is shown.

The reticle 115 is attached to the reticle drive stage 1
16, the X-ray mask 127 is preliminarily rough-aligned with the scan stage 129 by observing, for example, a TV image pattern (not shown), and the reticle 115 and the X-ray mask 127 are mutually aligned (aligned). deep. So-called pre-alignment. The reticle 115 aligns the reticle AA pattern as a target with the alignment systems 111 and 112 with respect to the detection system systems 111 and 112 on the apparatus side. As the AA method in this case, various methods already used in the world can be used. Also, the reticle 115 and the X-ray mask 12
Similarly, the alignment means for aligning 7 can use the method already used in the world.

For example, (A) A diffraction grating is provided on a reticle and a wafer (corresponding to an X-ray mask in the case of the present invention), and a laser beam is applied to the diffraction grating to detect the deviation between the reticle and the wafer from the intensity of the diffracted light. Japanese Jorrnal of
Applied Physics Vol.24, No.11, NOV.1985 pp.1555-1560
reference. (B) A laser beam is scanned at a high speed on a chevron-type mark on the reticle and the wafer where x- and y-dimensional position information can be obtained, and reflected light from the mark is detected,
The deviation is detected from the time interval of the reflected light.

Sensor Technology February 1985 (Vol.5, N
o.2) pp. See 23-27. (C) T the pattern provided on the reticle and the wafer.
An image processing method in which a V image is recognized and the image shift is obtained by lattice processing to detect the shift. Electronic Materials March 1989 pp. 69-74.

By using any of these methods, reticle alignment (positioning the reticle with respect to the scanning exposure apparatus) and detection of mutual positional deviation between the reticle 115 and the X-ray mask 127 can be performed with high accuracy at the level of several nm. It can be detected.

In FIG. 5, reticle alignment (alignment for positioning the reticle 115 with respect to the scan exposure machine) and mutual alignment of the reticle 115 and the X-ray mask 127 are described above (A). ) Or,
The alignment may be performed by either method of (B) or (C). The alignment pattern may be a diffraction grating pattern in the case of (A), a chevron type mark in the case of (B), or a pattern as shown in FIG. 7 in the case of (C).

That is, the pattern S of stitching AA
The patterns of AA (x) and SAA (y) use such patterns. In the case of reticle alignment, a pattern corresponding to each of these methods (A), (B), and (C) may be used as the R / AA mark. However, in the case of reticle alignment, in each of the methods (A), (B), and (C), a pattern corresponding to the alignment pattern on the wafer is provided as the reticle alignment pattern RAA, and (A), Marks corresponding to the reticle side alignment marks in each of the methods (B) and (C) are provided, and the reticle 115 is positioned with respect to the scan exposure apparatus. The reticle 115 and the X-ray mask 127 are scanned in the y-axis direction in FIG. 5 at a scan speed ratio of N: 1. However, at this time, the exposure light 130 is blocked by the shutter. During the process of scanning, the light flux of the alignment detection systems 111 and 112 and the detection area are SAA.
(X) 73, 96, SAA (y) 71, 90 When the area is reached, the AA signal is taken at a timing, and after further scanning, SAA (x) 83, 100, SA
When the pattern area of A (y) 81, 98 is reached, the AA signal is taken at a timing and the reticle 115 is extracted from the signal.
After calculating the shift between the X-ray mask 127 and the X-ray mask 127, the X, Y stage 129 and the rotary stage 131 in the XY plane are moved to accurately align the reticle 115 with the X-ray mask 127. After that, the exposure light 130 is irradiated to perform scanning for printing. In the case of a so-called mass-production slapper which is printed on a wafer, throughput is required for an 8 ″ wafer, for example, about 60 sheets / hour, but for X-ray mask production, the throughput may be lower, so the scanning speed is It can be low, ie the exposure time can be long.

Further, the reticle is more effective if a phase shift mask is adopted in order to increase the resolution and the depth of focus. For details of the phase shift mask, see Nikkei Microdevices July 1990 issue p. See 103-114.
Further, if so-called modified illumination is adopted for the illumination system, the resolution and the depth of focus can be improved. For the details of modified illumination, see Nikkei Microdevices April 1992 p. 28-39.

Next, 1-1-2. An example will be described in which the position is adjusted with the stage feed accuracy.

In this case, the stitching AA is not relied upon, and the pattern A and the pattern B shown in FIG. 6 are connected by the positional information of the stage and the feed accuracy. In this case, therefore, the stitching alignment patterns SAA (x) 72, 96 and SAA (y) 71, 9 in FIGS.
0, SAA (x) 83,100, SAA (y) 81,9
8 is unnecessary. Further, in FIG. 5, it is not necessary to use the function of stitching AA for connecting the A pattern and the B pattern. Instead, the length measuring means 132 for giving the position information of the stage 116 and the length measuring means 133 for giving the position information of the scan stage 129 of the X-ray mask 127.
Then, the reticle alignment means 111 and 112 are utilized. That is, the reticle A and the reticle B are set in the exposure apparatus, respectively, and then the scanning exposure apparatus is positioned with high accuracy by using the alignment means. As a result, for example, a sensor on the exposure apparatus side is used as a reference object for alignment, and even after the reticle A is changed to B, highly accurate reproducibility with respect to the exposure apparatus, that is, the alignment detection sensor (stored in 111 and 112). Be positioned with. At this time, in FIG. 5, rotational alignment is performed by the rotary stage 137 that can rotate the reticle while smiling. Although the scan stage 116 can scan in the y direction, it has a smile moving stage (not shown) in the x direction for adjustment.

After the reticle 115 is aligned with the exposure apparatus side, the image forming system 138 is focused between the X-ray mask 127 and scan exposure. At this time, the positional information of the stages 116 and 129 is obtained with high accuracy by the length measuring means 132 and 133, respectively, and after changing the reticle to another reticle, the reticle is aligned and the length measuring devices 116 and 133 are subjected to the aforesaid measurement. Referring to the length measurement value, the stage 129 is shifted by a certain distance in the x-axis direction so that the patterns A and B are connected and lined up on the X-ray mask, and then the value of the length measurement value in the y-axis direction is also measured. And scan exposure. As a result, an X-ray mask that can be connected with high precision can be obtained by utilizing the length measuring means 132, 133 of the stages 116, 129 instead of the function of stitching AA for connecting the A pattern and the B pattern. The A pattern and the B pattern may be substantially the same IC pattern or different patterns.

Next, when the phenomenon occurs after the A pattern exposure and the B pattern exposure, A,
Alignment measuring means 11 is performed by connecting the B pattern.
The case of not relying on 1 or 112, that is, the case of 1-2-1 will be described. Also in this case, the above-mentioned 1-1-
It may be performed in the same manner as in the case of 2. Reticle stage 11
6 and the stage 129 of the X-ray mask and the length measuring means 132 and 133 for measuring the respective positions. That is, after aligning the reticle 115 with respect to the exposure apparatus side as shown in FIG. 5, the focus of the imaging system 138 is set to the X-ray mask 12.
7 and scan exposure. Stage 11 at this time
The position information of 6 and 129 are obtained with high precision by the length measuring means 132 and 133, respectively, and after changing the reticle to another reticle, the reticle is aligned with the exposure device, and then the length measuring devices 116 and 133 are measured. With reference to the length measurement value of, the stage 129 is shifted in the x-axis direction by a certain distance so that the patterns A and B are connected and lined up on the X-ray mask, and then the value of the length measurement value in the y-axis direction is obtained. Exposure scan based on. Thus, instead of the function of stitching AA for connecting the A pattern and the B pattern, the stage 116,
By utilizing the length measuring means 132 and 133 of 129, an X-ray mask which can be connected with high precision can be obtained. Cases 1-1 up to this point 1-1-1, 1-1-2, 1-2-1, 1-2
In both cases, both negative and positive resists can be used, and at that time, the area of the exposed portion may be set in reverse. 1-2-2
An example of the case will be described. That is, a case will be described in which alignment between A patterns and B patterns (similar to alignment between layers) is performed when A patterns are exposed and B patterns are exposed and developed. in this case,
A so-called latent image alignment is used, which will be described below. A resist causes a photochemical reaction when irradiated with light, but it also causes a change in transmittance and a refractive index in an optical sense, or in a special case, a surface step difference with a non-irradiated part due to expansion or contraction. Occurs. Even in a commonly used resist, the result of exposure can be observed as a grayscale image under a white light microscope. In the following description, this image is referred to as a latent image for convenience. Latent image alignment is a method that utilizes a partial change in the resist layer resulting from exposure.
The resist latent image is a wafer (in the case of the present invention, an X-ray mask)
Since it is the alignment mark image of the reticle formed on the photoresist, the registration latent image can be aligned with a small error by detecting the relative positional relationship with the latent image using the resist latent image.

That is, referring to FIGS. 2, 3 and 4,
After the exposure on the X-ray mask with the reticle having the pattern A as in the case of FIG. 2, the area other than the hatched portion of FIG. , 83, SAA (y) 7
1, 81 are also formed as a resist latent image on the X-ray mask. Therefore, as shown in FIG. 3, the stitching alignment is changed to the case 1-1-1 by changing to the B pattern reticle.
As in the case of, the process is performed using the latent resist image. That is,
The resist latent image alignment pattern SAA (x) 73 is combined with the SAA pattern on the reticle side of the SAA (x) 96, and the pattern SAA on the reticle is similarly formed.
(X) 100 has SAA as a resist latent image pattern
(X) 83 of SAA (y) 98 SAA
The resist latent image pattern of (y) 81 is changed to SAA (y) 9
The resist latent image patterns of SAA (y) 71 are used as a pair of alignment patterns, respectively. Case 1-1 regarding the use of alignment detection devices and methods
The same as the contents described in -1 is possible.

Next, an example will be described in which, when there is a scribe line between the A pattern and the B pattern, the A pattern is exposed and the resist phenomenon is performed, and then the resist is applied and the B pattern is exposed and the resist phenomenon is performed. An example of case 2-1-1 in the case of performing alignment between pattern A and pattern B (similar to alignment between layers) will be specifically described. FIG. 9 shows a layout when there is a scribe line 150 between the A pattern and the B pattern. When the scribe line 150 is provided, the pattern A and the pattern B may be separated and used as one chip. At this time, stitching AA patterns, SAA (x) or SAA (y) and overlay patterns OLA (x), OLA (y), OLB (x), O are also formed on the area of the scribe line 150.
It is possible to provide LB (y). An example of this case is shown in FIGS. RAA, MAA, SAA, O
The LA, OLB, WAA, and NEXT layers all have the same meanings as in FIGS. 2 and 3, and the reticle alignment pattern, the mask (x & y mask) alignment pattern, the stitching alignment pattern, and the overlay that is simultaneously printed on the X-ray mask during exposure of the A pattern. (Overlay error) X when detecting mark and B pattern exposure
Overlay detection mark, IC printed on line mask
Means a pattern on the X-ray mask side for aligning the wafer and the X-ray mask in the process of forming a wafer, and a pattern (NET layer pattern) for printing on the wafer side for aligning the next layer. There is. As shown in the figure, the overlay detection marks OLA (x) 162, 16 are formed in the area corresponding to the scribe line 150.
4, OLA (y) 163, 165, OLB (x) 17
6, 178 and OLB (y) 175, 177 are laid out. The relationship between the function of each pattern and the alignment device is 1-1-1, 1-1-2, 1-2-1,
It may be similar to the case of 1-2-1. In the area corresponding to the scribe line 150, not only the overlay detection mark but also the stitching pattern SAA (x) or S
It is also possible to lay out the AA (y) pattern. That is, it is possible to arrange the overlay detection mark and the stitching alignment pattern in the area corresponding to the scribe line 150. If the number of layers is relatively small in the IC manufacturing process, W
An AA pattern or NEXT layer pattern may be provided. Further, it goes without saying that the A pattern and the B pattern are not limited to the patterns different from each other, and the case where the IC circuit patterns of the A pattern and the B pattern are exactly the same pattern is applicable.

In FIGS. 10 and 11, the scan direction of the scan exposure is the y direction, and W ′ is the exposure width, which is given by an aperture or the like that determines the illumination width of the exposure light that illuminates the reticle 115. The aperture that determines the illumination width of the exposure light may be placed at a position substantially conjugate with the reticle 115 via a lens, or may be placed immediately before the reticle as shown in FIG. Further, L ″ and L ′ ″ are scan lengths at the time of exposure, W ′ × L ″ is an exposure illumination area in FIG. 10, and W ′ × L ″ is an exposure illumination area in FIG. 11. It is needless to say that the exposure light actually shines on the X-ray mask 127 in the area not shaded and depends on the pattern of the reticle 115.

When the scribe line 150 is used and the position is aligned with the stage feed accuracy, that is, Case 2-1.
In the same manner as in case 2, case 1-1-2 may be performed. The only difference is that the pattern layout is provided in an area corresponding to the scribe line area 150.

Also, the case 2-2-1 in which the A pattern is exposed and the B pattern is exposed and then developed is also the case 1-2.
In the case 2-2-2, the latent image alignment may be performed in the same manner as in the case 1-2-2 as in the case 1.

Further, although the embodiments have been described above on the side of light exposure light (i-line 365 nm, KrF 248 nm, ArF 193 nm), the case of X-ray reduction scan exposure in which printing is performed by exposing X-rays in exactly the same manner. Can also be applied. In the case of X-ray exposure, a lens having a wavelength used is usually several Å to 200 Å.

Further, in the above, the X-ray mask has mainly been described as a unit-size X-ray mask using prokinetic exposure, but the unit is not limited to the unit-size X-ray mask, and may be reduced by, for example, 1 / N. It may be an X-ray mask or the like.

Further, the connection of the patterns is not limited to the example of A and B2 patterns, but may be the case of 3 patterns or 4 patterns as shown in FIGS.

Next, an embodiment of a device manufacturing method using the above-described mask and exposure apparatus will be described. FIG. 14 is a minute device (semiconductor chip such as IC or LSI, liquid crystal panel, CCD, thin film magnetic head, microsyringe, etc.)
3 is a flowchart showing a manufacturing process of. Step 71
In (Circuit design), the circuit of the semiconductor device is designed. In step 72 (mask manufacturing), a mask having the designed circuit pattern is manufactured. This mask is a reflective mask and has the features described above. On the other hand, in step 73 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 74 (wafer process) is called a pretreatment process, and an actual circuit is formed on the wafer by the lithographic technique using the mouse and the wafer prepared above. The next step 75 (assembly) is called a post-process, which is a process of forming a semiconductor chip using the wafer created in step 74, such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), and the like. including. In step 76 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 75 are performed. Through these steps, the semiconductor device is completed and shipped (step 77).
To be done.

The main purpose of the present invention is to solve the problem at the time of patterning by the exposing means and the drawing means in the process of producing the X-ray mask structure. However, the mask formed by the method of the present invention. A specific example of the manufacturing process of the X-ray mask structure using the pattern is shown below.

FIG. 15 shows a first specific example of the manufacturing process of the X-ray mask structure. First, in (a), an X-ray transparent film such as silicon nitride 12 is formed on the surface of a silicon wafer 11 whose both sides are to be polished later by polishing by chemical vapor deposition. Next, in (b), silicon is etched from the back surface of the wafer in a region where a pattern is to be formed later to form a free-standing film of the X-ray transparent film. In (c), 5n of Cr13 and Au14 each serving as an electrode for plating are formed on the X-ray transparent film.
Successive vapor deposition is performed by an EB vapor deposition device so that the film thickness becomes m and 50 nm. In (d), the resist 15 is further applied, and a pattern is formed by an optical exposure means such as a stepper, an electron beam drawing device, or the like. The point of the present invention lies in the method of patterning at this time. Then, in (e), a heavy metal such as Au16 is deposited in the gap between the resist patterns by a plating method to remove the resist. Then, (f)
Then, the exposed electrode portion of the non-patterned portion is subjected to oxidation and transparency treatment by Au sputtering and O ₂ RIE to obtain an X-ray mask structure. Finally, in (g), this substrate is bonded to a reinforcing frame 17 made of Pyrex glass, silicon carbide, titanium alloy or the like with an adhesive 18 such as an epoxy type. When the X-ray mask is held using the magnetic chuck in the X-ray exposure apparatus, the magnetic material 19 is further bonded to the mask frame 17 in (h).

Further, FIG. 16 shows a second specific example of the manufacturing process of the X-ray mask structure.

First, an X-ray transparent film such as silicon nitride 22 is formed on the surface of a silicon wafer 21 whose both sides are polished in (a), which will later become a support frame, by a chemical vapor deposition method. Next, in (b), silicon is etched from the back surface of the wafer in a region where a pattern is to be formed later to form a free-standing film of the X-ray transparent film. At (c), the etching stopper layer 23 and the X-ray absorber film 24 are formed on the X-ray transparent film by the sputtering method. Next, PMM which is electron beam resist
A resist 25 such as A or a photoresist is applied.
In (d), a pattern is formed by an optical exposure means such as a stepper, an electron beam drawing device, or the like. Then, in (e),
The X-ray absorber film is dry-etched using this resist as a mask to form a pattern. Subsequently, in (f), the exposed etching stopper layer 23 in the non-patterned portion is removed, and X
Obtaining a line mask structure. Finally, in (g), this substrate is bonded to a reinforcing frame 26 made of Pyrex glass, silicon carbide, titanium alloy or the like with an adhesive 27 such as an epoxy type adhesive. When the X-ray mask is held using the magnetic chuck in the X-ray exposure apparatus, the mask frame 26 is set in (h).
The magnetic body 28 is further adhered to.

[0059]

As described above, according to the present invention, a high resolution (fine pattern) and a wide pattern can be obtained by combining the reduction scan exposure apparatus with the pattern continuous exposure technique.
An X-ray mask required to be fielded can be realized at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an arrangement on an X-ray mask pattern.

FIG. 2 is a diagram illustrating printing of an A pattern according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating printing of a B pattern according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating an arrangement in which patterns A and B are printed in an embodiment of the present invention.

FIG. 5 is a diagram showing an embodiment of the scanning exposure apparatus of the present invention.

FIG. 6 is a diagram showing an overlay detection method.

FIG. 7 is a drawing of another example showing an overlay detection method.

FIG. 8 is a drawing of another example showing an overlay detection method.

FIG. 9 is a diagram illustrating an arrangement on an X-ray mask pattern.

FIG. 10 is a drawing for explaining printing of the A pattern when there is a scribe area between the A pattern and the B pattern in the embodiment of the present invention.

FIG. 11 is a diagram for explaining the printing of the B pattern when there is a scribe area between the A pattern and the B pattern in the embodiment of the present invention.

FIG. 12 is a diagram showing an example of an array in the case of 3-pattern connection.

FIG. 13 is a diagram showing an example of an array in the case of 4-pattern connection.

FIG. 14 is a flowchart showing manufacturing steps of a semiconductor device.

FIG. 15 is a diagram showing an example of a manufacturing process of an X-ray mask structure.

FIG. 16 is a diagram showing an example of a manufacturing process of an X-ray mask structure.

[Explanation of symbols]

71 to 102 patterns for various alignments 111 alignment detection system 112 alignment detection system 114 slit aperture 115 reticle 116 reticle large 117 reticle large drive system 118 reticle holder 119 mirror 120 lens system 121 mirror 122 mirror 123 lens system 124 focus detection System 125 Focus detection system 126 Control system 127 X-ray mask that is the exposed object 128 Tilt stage 129 X, Y large 130 Illumination light beam 132 Length measuring machine that measures the movement of reticle large 133 Length measuring device that measures the movement of the X-ray mask Machine 137 Rotation stage 138 Imaging system 141a Diffraction grating pattern 141b Diffraction grating pattern 150 Scribe line 151-182 Various arrays Pattern 11 silicon wafer 12 X-ray transparent film 13 Cr deposited film 14 Au deposited film 15 Resist 16 Heavy metal deposited by plating 17 Reinforcement frame 18 Adhesive 19 Magnetic material 21 Silicon wafer 22 X-ray transparent film 23 Etching Stopper layer 24 X-ray absorber film 25 Resist 26 Mask frame 27 Adhesive 28 Magnetic substance

Front page continued (72) Inventor Hiro Maehara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. A method for manufacturing a mask, comprising forming a mask pattern by using a plurality of original plates and transferring the patterns of these original plates side by side in a predetermined positional relationship on a substrate by scanning reduction exposure. . 2. A mask according to claim 1, wherein each original plate is provided with a predetermined detection mark, and the patterns of each original plate are arranged in a predetermined positional relationship based on the detection of the detection mark. Production method. 3. The method of manufacturing a mask according to claim 1, wherein the mask is an X-ray mask. 4. The method of manufacturing a mask according to claim 1, wherein the exposure is performed with light in a wavelength range of ultraviolet rays or X-rays. 5. A mask manufactured by the manufacturing method according to claim 1. 6. A means for transferring an original pattern onto a substrate by scanning reduction, a means for detecting a predetermined detection mark of the original, and a plurality of original patterns in a predetermined positional relationship based on the detection of the detection mark. An apparatus for manufacturing a mask, characterized in that it has means for arranging them side by side and transferring them to a substrate.