JP5324206B2 - Alignment method, photomask and wafer - Google Patents

Description

  The present invention relates to an alignment method in photolithography technology.

  Conventionally, an optical lithography technique is known as a technique for manufacturing a semiconductor element such as a large-scale integrated circuit (LSI). This photolithographic technique is to apply a photosensitive organic material called photoresist onto a semiconductor wafer such as silicon or gallium arsenide, and use an exposure device called a photostepper, photoscanner, photoaligner, etc. This pattern is printed on the photoresist. By developing this photoresist and selectively etching the wafer directly under the photoresist, an electronic circuit is formed on the wafer.

  In such a photolithographic technique, when a pattern drawn on a photomask is printed on a photoresist by an exposure apparatus, it is necessary to accurately align the wafer and the photomask. In particular, when the electronic circuit has a laminated structure, if the position of the wafer and the photomask is misaligned, a connection failure occurs between the lower layer circuit and the upper layer circuit, so accurate alignment is important. It is.

Techniques for performing this alignment can be roughly classified into two.
The first is an alignment technique for producing an extremely small submicron electronic circuit typified by a large scale integrated circuit, which is performed using an exposure apparatus called a photostepper or a photo scanner. This exposure apparatus transfers a very small pattern onto a photoresist by reducing projection exposure while moving a large photomask on which a pattern several times (4 times, 5 times) larger than the actual size is moved on the wafer. (For example, refer nonpatent literature 1.). In this case, alignment must be performed at least in two places, between the photomask and the exposure apparatus, and between the exposure apparatus and the wafer, and must be performed with high accuracy in order to produce an extremely small electronic circuit. I must. For this reason, conventionally, the entire system is controlled while monitoring all related components with a highly accurate interferometer. Therefore, since the apparatus configuration becomes large-scale, the operation is complicated and the cost is high.

  On the other hand, the second is an alignment technique for producing a relatively large electronic circuit that requires an accuracy of about 1 μm, and uses an exposure apparatus called a contact aligner or a 1 × pattern transfer machine. Is to be done. In this case, a simple cross mark is formed on the wafer, and a mark surrounding the cross mark is formed on the photomask, and the gap between the marks when viewed from the distance direction of the wafer and the photomask. Is performed by moving the stage on which the wafer is mounted while the operator observes the mark with the naked eye using a magnifying glass. Therefore, since the second alignment technique can be realized with a simpler apparatus configuration than the first alignment technique, the operation is simple and the cost can be reduced.

Tadakawa Tadahiro et al., “Innovation of ULSI Lithography Technology”, 1st edition, Science Forum, Inc., November 10, 1994, p. H.264

  However, in the second alignment technique described above, the accuracy largely depends on the appearance of the mark. Therefore, depending on the performance of the magnifier and the physical condition of the operator, it is difficult to achieve the alignment with the desired accuracy. there were.

  Accordingly, an object of the present invention is to provide an alignment method, a photomask, and a wafer that can realize more accurate and simple alignment.

  In order to solve the above-described problem, an alignment method according to the present invention is based on a first mark formed on a photomask and a second mark formed on a wafer. And aligning the photomask and the wafer by relatively translating the wafer optically arranged in parallel, wherein the first mark comprises a light transmitting window, The second mark constitutes a reflection part that reflects light, and the first mark and the second mark are formed in a rectangular shape having a diagonal line parallel to the moving direction, and are reflected by the second mark. The photomask and the wafer are aligned based on the amount of reflected light transmitted through one mark.

  In the above alignment method, a plurality of first marks and second marks may be formed. The first mark and the second mark may be formed on a straight line. Furthermore, the first mark and the second mark may be formed on the circumference of a concentric circle.

A photomask according to the present invention is a photomask used in the alignment method, and includes the first mark.
In addition, a wafer according to the present invention is a wafer used for the alignment method and includes the second mark.

  According to the present invention, the first mark is composed of a window that transmits light, the second mark constitutes a reflecting portion that reflects light, and the first mark and the second mark are diagonal lines parallel to the moving direction. The wafer is aligned with the photomask by aligning the photomask and the wafer based on the amount of reflected light that is reflected by the second mark and transmitted through the first mark. If the relative movement is made, the portion where the first mark and the second mark overlap changes in a quadratic function, so the amount of reflected light transmitted through the first mark also changes. Based on this change, By aligning the wafer and the photomask, more accurate and simple alignment can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Configuration of exposure apparatus>
FIG. 1 is a diagram schematically showing an internal configuration of an exposure apparatus that uses the alignment method according to the present embodiment. The exposure apparatus shown in FIG. 1 is used for exposure, with a stage 1 having a placement surface 11 on which a wafer 3 is placed, a support portion (not shown) that opposes and places a photomask 2 substantially parallel to the placement surface. A light source (not shown). In such an exposure apparatus, a wafer 3 coated with a resist is placed on a placement surface 11 of a stage 1 movable in the X direction and the Y direction, and the wafer 3 is exposed through the photomask 2 to thereby form the photomask 2. The formed pattern 21 is transferred to a resist. After the exposure, when the wafer 3 is immersed in a developing solution to remove excess resist, a pattern 31 corresponding to the pattern 21 of the photomask 2 is formed on the wafer 3.
In the following description, one direction along the plane of the mounting table 11 is the X direction, a direction along the plane of the mounting table 11 and orthogonal to the X direction is the Y direction, a direction orthogonal to the X direction and the Y direction, That is, the distance direction between the stage 1 and the photomask 2 is the Z direction. Further, in the X direction, the direction from left to right with respect to the paper surface of FIG. 1 is positive, in the Y direction, the direction from the near side to the back with respect to the paper surface of FIG. 1 is positive, and in the Z direction, the paper surface of FIG. The direction from bottom to top is positive.

  The photomask 2 has a substantially rectangular shape in plan view, and is composed of a photomask on which a predetermined pattern 21 is formed. For example, the photomask 2 has a length in the X direction of 120 [mm] and a length in the Y direction of 120 [mm]. In such a photomask 2, as shown in FIG. 2, a pair of alignment portions 22 are formed in the vicinity of the substantially central portions of both sides along the Y direction. The alignment unit 22 is formed by an electron beam drawing apparatus or the like. Details of the alignment unit 22 will be described later.

  The wafer 3 is a wafer on which a predetermined circuit such as a silicon wafer is formed. For example, the wafer 3 is composed of a silicon wafer having a diameter of 100 [mm]. In such a wafer 3, as shown in FIG. 3, a pair of alignment portions 32 are formed in the vicinity of the edge portion of the wafer 3 so as to sandwich an area where a predetermined pattern 31 is formed. The alignment unit 22 is formed by an electron beam drawing apparatus or the like. Details of such an alignment unit 32 will be described later.

<Configuration of alignment unit>
Next, the configuration of the alignment units 22 and 32 will be described with reference to the configuration.

<< Configuration of Positioning Unit 22 >>
As shown in FIG. 4, the alignment portion 22 formed on the photomask 2 is formed of concentric circles of the center 200, and the first to fourth circles 201 to 204 whose diameter increases by a predetermined length, The first to twentieth line segments 211 to 230 made of line segments corresponding to the radius of the circle 204, the intersection of the first to fourth circles 201 to 204 and the first to twentieth line segments 211 to 230, or It comprises a plurality of window portions 240 formed in the vicinity of the intersection. For example, the diameter of the fourth circle 201 is 50 [μm], and the interval between the first to fourth circles 201 to 204 is 10 [μm].

Here, the first line segment 211 is a line segment extending from the center 200 in the positive direction of the X direction to the circumference of the fourth circle 204, and the second to fifth line segments 212 to 215 are The first line segment 211 is formed by rotating the first line segment 211 counterclockwise and clockwise by 5 ° and 10 ° with the center 200 as the rotation center.
The sixth line segment 216 includes a line segment extending from the center 200 to the circumference of the fourth circle 204 in the positive direction of the Y direction, and the seventh to tenth line segments 217 to 220 are the center. The first line segment 211 is formed by rotating the first line segment 211 counterclockwise and clockwise by 5 ° and 10 ° with 200 as the rotation center.
The eleventh line segment 221 is a line segment extending from the center 200 in the negative X direction to the circumference of the fourth circle 204, and the twelfth to fifteenth line segments 222 to 225 are center lines. The eleventh line segment 211 is formed by rotating the eleventh line segment 211 by 5 ° and 10 ° counterclockwise and clockwise about 200 as the rotation center.
The sixteenth line segment 226 is a line segment extending from the center 200 to the circumference of the fourth circle 204 in the negative direction of the Y direction, and the seventeenth to twentieth line segments 227 to 230 are the center. The sixteenth line segment 226 is formed by rotating the sixteenth line segment 226 counterclockwise and clockwise by 5 ° and 10 °, respectively, with 200 as the rotation center.

  Moreover, the window part 240 consists of an opening which has a rectangular shape with a diagonal along the X direction and the Y direction. For example, the reflecting portion 340 has a square shape with a side of 2 [μm]. Note that the window 240 is not limited to an opening as long as light is transmitted. For example, a portion corresponding to the window 240 may be shaved thinner than the surroundings.

Such a window part 240 is formed in the position shown below.
First, a line segment along the X direction or the Y direction, that is, the first line segment 211, the sixth line segment 216, the eleventh line segment 221, the sixteenth line segment 226, and the first to fourth circles 201. In the intersection with -204, the window part 240 is formed so that this intersection and the intersection of a diagonal line may correspond.
In addition, with respect to the intersection of the nth line segment and the first to fourth circles 201 to 204 clockwise and counterclockwise from the first line segment 211 or the eleventh line segment 221 with respect to the center 200, The window 240 is formed so that the intersection of the diagonal lines is located at a position of 0.1 × n [μm] in the direction away from the first line segment 211 or the eleventh line segment 221 along the Y direction from the intersection. Is done.
Similarly, the intersection of the nth line segment and the first to fourth circles 201 to 204 clockwise and counterclockwise from the sixth line segment 216 or the sixteenth line segment 226 with respect to the center 200 is as follows. The window 240 is arranged such that the intersection of the diagonal lines is located at a position of 0.1 × n [μm] in the direction away from the sixth line segment 216 or the sixteenth line segment 226 along the X direction from the intersection point. It is formed.

  For example, as shown in FIG. 5, the intersection of the first circle 201 and the second circle 202 and the second line segment 212 is 0.1 [μm] away from the intersection in the positive direction of the Y direction. A window 240 is formed at the position where the intersections of the diagonal lines coincide.

  In any case, the window 240 has a rectangular shape with diagonal lines along the X direction and the Y direction, regardless of the position where it is formed.

<< Configuration of Positioning Unit 32 >>
As shown in FIG. 6, the alignment portion 32 formed on the wafer 3 includes first to fourth circles 301 to 304 that are concentric circles of the center 300 and have a diameter that increases by a predetermined length, and a fourth circle. At the intersections of the first to twentieth line segments 311 to 330 made of line segments corresponding to the moving radius of 304, the first to fourth circles 301 to 304, and the first to twentieth line segments 311 to 330. The reflection part 340 is formed. For example, the diameter of the fourth circle 301 is 50 [μm], and the interval between the first to fourth circles 301 to 304 is 10 [μm].

Here, the first line segment 311 is composed of a line segment extending from the center 300 in the positive direction of the X direction to the circumference of the fourth circle 304, and the second to fifth line segments 312 to 315 are The first line segment 311 is formed by rotating the first line segment 311 counterclockwise and clockwise by 5 ° and 10 °, respectively, with the center 300 as the rotation center.
The sixth line segment 316 includes a line segment extending from the center 300 in the positive direction of the Y direction to the circumference of the fourth circle 304, and the seventh to tenth line segments 317 to 320 are the center. The first line segment 311 is formed by rotating the first line segment 311 counterclockwise and clockwise by 5 ° and 10 ° about the rotation center 300, respectively.
The eleventh line segment 321 is a line segment extending from the center 300 to the circumference of the fourth circle 304 in the negative direction of the X direction, and the twelfth to fifteenth line segments 322 to 325 are center lines. The eleventh line segment 311 is formed by rotating the eleventh line segment 311 counterclockwise and clockwise by 5 ° and 10 °, respectively, with 300 as the rotation center.
The sixteenth line segment 326 is a line segment that extends from the center 300 in the negative direction of the Y direction to the circumference of the fourth circle 304, and the seventeenth to twentieth line segments 327 to 330 are center lines. The sixteenth line segment 326 is composed of line segments obtained by rotating the sixteenth line segment 326 counterclockwise and clockwise by 300 and 300 respectively.

  In addition, the reflection unit 340 has a configuration in which a diagonal line has a rectangular shape along the X direction and the Y direction and reflects light. For example, the reflecting portion 340 has a square shape with a side of 2 [μm]. Such a reflection part 340 is formed in a layer different from the surroundings, or a part corresponding to the reflection part 340 is cut or the periphery of the reflection part 340 is cut so that the reflectance is higher than the surroundings. Although formed, the reflection realized by this is not necessarily specular.

  The reflection part 340 is formed such that the intersection of the diagonal lines coincides with the intersection of the first to fourth circles 301 to 304 and the first to twentieth line segments 311 to 330. For example, as shown in FIG. 7, a reflection portion 340 is formed at the intersection of the first circle 301 and the second circle 302 and the second line segment 312 so that the intersection of the diagonal lines coincides with this intersection. ing.

  In any case, the reflecting portion 340 has a rectangular shape with diagonal lines along the X direction and the Y direction, regardless of the position where it is formed.

  The alignment unit 22 and the alignment unit 32 described above are formed such that the distance between the centers 200 of the alignment units 22 is equal to the distance between the centers 300 of the alignment units 32. For example, the distance is 60 [mm].

<Positioning operation>
Next, an alignment operation between the photomask 2 and the wafer 3 in the exposure apparatus according to the present embodiment will be described. This alignment means an operation for positioning the alignment portion 22 of the photomask 2 and the alignment portion 32 of the wafer 3 at the same position when viewed from the Z direction.

  First, the wafer 3 is mounted on the mounting surface 11 of the stage 1. At this time, the wafer 3 is mounted on the mounting surface 11 after the rotation direction is adjusted based on an orientation flat portion 33.

  When the wafer 3 is placed, the user performs rough alignment between the photomask 2 and the wafer 3. This is because the stage 1 is moved in the X or Y direction while visually confirming the photomask 2 and the wafer 3 so that the alignment portion 22 of the photomask 2 and the alignment portion 32 of the wafer 3 are aligned in the Z direction. This is done by moving it. By such rough adjustment, the alignment portion 22 of the photomask 2 and the alignment portion 32 of the wafer 3 can be aligned with an accuracy of several tens [μm].

  When coarse adjustment is performed, coarse adjustment more precise than this coarse adjustment is performed. This rough adjustment is performed for each of the X direction and the Y direction.

  First, when performing coarse adjustment in the X direction, the user moves the stage 1 in the X direction while observing the alignment portion 22 of the photomask 2 with the naked eye or a magnifying glass in a state in which the wafer 3 is irradiated with visible light. Let The reflection unit 340 of the alignment unit 32 formed on the wafer 3 reflects the irradiated visible light toward the photomask 2, so that any of the reflection units 340 and any of the window portions 240 are in the Z direction. When aligned, the user can observe the reflected light from the reflecting portion 340 from the window portion 240. Thereby, the alignment part 22 of the photomask 2 and the alignment part 32 of the wafer 3 can be arranged at substantially the same position in the Z direction.

  At this time, the user is a window group composed of window portions 240 formed at or near the intersections of the first to fifth line segments 211 to 215 of the alignment unit 22 and the first circle 201 (FIG. 4). Note the symbol a). As shown in FIG. 6, the reflecting portions 340 are densely arranged in the Y direction in the alignment portion 32 of the wafer 3. In particular, a reflection portion group (indicated by symbol α in FIG. 6) composed of the reflection portion 340 formed at the intersection of the first to fifth line segments 311 to 315 and the first circle 301 corresponding to the window portion group a. ), The reflecting portions 340 are arranged more closely in the Y direction than the reflecting portion group formed at the intersections with the second to fourth circles 302 to 304. Therefore, when the wafer 3 is moved in the X direction, at least a part of any one of the window parts 240 in the window part group a and at least a part of any one of the reflection parts 340 in the reflection part group α are Z. It will be lined up in the direction. When the reflected light is observed from any of the window portions 240 in the window group a, the user adjusts the amount of movement of the stage 1 in the X direction so that the reflected light looks bright to some extent. When the reflected light appears bright to some extent, the coarse adjustment in the X direction is terminated.

  Next, rough adjustment in the Y direction is performed. In this case, as in the case of the coarse adjustment in the X direction, the stage 1 is moved in the Y direction while looking through the alignment portion 22 of the photomask 2 while irradiating the wafer 3 with visible light.

  At this time, the user is a window group composed of windows 240 formed at or near the intersection of the sixth to tenth line segments 216 to 220 of the alignment unit 22 and the first circle 201 (FIG. 4). (Indicated by the symbol b). As shown in FIG. 6, the reflecting portions 340 are densely arranged in the X direction in the alignment portion 32 of the wafer 3. In particular, a reflection portion group (indicated by reference symbol β in FIG. 6) composed of a reflection portion 340 formed at the intersection of the first to fifth line segments 311 to 315 and the first circle 301 corresponding to the window portion group b. ), The reflecting portions 340 are arranged more closely in the X direction than the reflecting portion group formed at the intersections with the second to fourth circles 302 to 304. Therefore, when the wafer 3 is moved in the Y direction, at least a part of any one of the window parts 240 in the window part group b and at least a part of any one of the reflection parts 340 in the reflection part group β are Z. It will be lined up in the direction. When the reflected light is observed from any of the window portions 240 in the window group b, the user adjusts the amount of movement of the stage 1 in the Y direction so that the reflected light looks bright to some extent. When the reflected light appears to be bright to some extent, the coarse adjustment in the Y direction is terminated.

  When coarse adjustment is completed, fine adjustment is performed last. This fine adjustment is performed for each of the X direction and the Y direction.

  First, fine adjustment in the X direction is performed. At this time, the user is a window formed of the window 240 formed at or near the intersection of the sixth to tenth line segments 216 to 220 of the alignment unit 22 and the second to fourth circles 202 to 204. Note the subgroup (indicated by symbol c in FIG. 4). This window portion group corresponds to the reflection portion group (indicated by reference numeral γ in FIG. 6) in the alignment portion 32 of the corresponding wafer 3, that is, the sixth to tenth line segments 316 to 320 and the second to fourth circles. The position of the stage 1 in the Y direction is adjusted so that the reflecting portion group γ composed of the reflecting portions 340 formed at the intersections with 302 to 304 matches in the Z direction. Specifically, the stage 1 so that the window part 240 on the sixth line segment 216 in the window part group c and the reflection part 340 on the sixth line segment 316 in the reflection part group γ coincide with each other in the Z direction. The position in the Y direction is adjusted. Since these are formed along the X direction at the same interval and in the same shape, they can be matched. Therefore, the user can observe the reflected light from all the window portions 240 on the first line segment 211 in the window group c, and the position of the stage 1 in the Y direction so that the amount of the reflected light is maximized. Adjust.

  Here, the window part 240 and the reflection part 340 have a rectangular shape with diagonal lines along the X direction or the Y direction. Therefore, if the stage 1 is moved in the X direction or the Y direction when the window part 240 and the reflection part 340 overlap with each other in the Z direction, the amount of reflected light from the reflection part 340 that can be observed in the window part 240 is secondary. It changes functionally. This phenomenon will be described with reference to FIG.

Assuming that the length of one side of the window 240 and the reflection part 340 is L, when these exactly match, the area S _all of the overlapping portion is L × L. On the other hand, if it is deviated by Δx in the X direction from the strictly matched state, the area S ₁ where the window portion 240 and the reflecting portion 340 overlap is expressed by the following equation (1).

S ₁ = (L−Δx / 2 ^1/2 ) × (L−Δx / 2 ^1/2 )
^{= L × L-2 1/2 ×} L × Δx + Δx 2/2 ··· (1)

As described above, the area S ₁ where the window 240 and the reflecting portion 340 overlap is expressed by a quadratic function of Δx. Therefore, when the stage 1 is moved in the X direction or the Y direction, the area S ₁ changes in a quadratic function, so the amount of reflected light that can be observed from the window 240 also changes in a quadratic function. Since the amount of light changes in a quadratic function in this way, the user can detect the change in the amount of light more sensitively, and as a result, the stage 1 is more easily positioned at a position where the amount of reflected light is maximized. Can be adjusted.

  Moreover, the window part 240 contained in the window part group c is formed so that it may shift | deviate along an X direction as it leaves | separates from the 6th line segment 216. FIG. For this reason, the light quantity observed from the window part 240 of the window part group c will change for every set of the window parts 240 arranged in the Y direction. Therefore, when the window part 240 on the sixth line segment 216 coincides with the corresponding reflection part 340 in the Z direction, the maximum light amount is detected from those window parts 240, but the sixth line segment 216 The first light amount lower than the maximum light amount from the window 240 in the vicinity of the seventh line segment 217 and the ninth line segment 219, which are adjacent line segments, is two adjacent to the sixth line segment 216. A second light amount that is lower than the first light amount is detected from the window 240 in the vicinity of the eighth line segment 218 and the tenth line segment 210. Therefore, the position of the stage 1 is finely adjusted so that the amount of light detected from the set of window portions 240 arranged in the Y direction decreases as the distance from the sixth line segment 216 decreases.

  As described above, according to the present embodiment, the amount of light observed from the window 240 changes for each set of the windows 240 arranged in the Y direction, so that the user detects the change in the amount of light more sensitively. As a result, the position of the stage 1 can be easily adjusted to a position where the amount of reflected light is maximized.

  When fine adjustment in the X direction is completed, the user performs fine adjustment in the Y direction by the same method. In this case, the user has a window made of the window 240 formed at or near the intersection of the first to fifth line segments 211 to 215 of the alignment unit 22 and the second to fourth circles 202 to 204. Note the subgroup (indicated by d in FIG. 4). This window portion group corresponds to a reflection portion group (indicated by reference numeral δ in FIG. 6) in the alignment portion 32 of the corresponding wafer 3, that is, first to fifth line segments 311 to 315 and second to fourth circles. The position of the stage 1 in the X direction is adjusted so that the reflecting portion group δ composed of the reflecting portions 340 formed at the intersections with 302 to 304 matches in the Z direction.

  When the fine adjustment in the X direction and the Y direction is thus performed, the alignment unit 22 of the photomask 2 and the alignment unit 32 of the wafer 3 are located at the same position in the Z direction.

  As described above, according to the present embodiment, the window part 240 and the reflection part 340 are formed in a rectangular shape having a diagonal line parallel to the moving direction, and reflected by the reflection part 340 and transmitted through the window part 240. When the wafer 3 is moved relative to the photomask 2 by aligning the photomask and the wafer based on the amount of light, the portion where the window 240 and the reflecting portion 340 overlap is expressed as a quadratic function. Since the amount of reflected light that can be observed from the window 240 also changes in a quadratic function, the user can more sensitively detect the change in the amount of light, and the amount of reflected light can be more easily detected. Since the position of the stage 1 can be adjusted to the maximum position, as a result, more accurate and simple alignment can be realized.

  In addition, according to the present embodiment, by providing a plurality of window portions 240 and reflection portions 340, even when the shapes of the window portions 240 and the reflection portions 340 vary depending on the processing accuracy, the average value of the amount of reflected light By adjusting the position of the stage 1, the positioning can be performed with high accuracy.

  Further, according to the present embodiment, by providing the window 240 and the reflector 340 on a straight line, the alignment unit 22 of the photomask 2 and the alignment unit 32 of the wafer 3 are located at the same position in the Z direction. In this case, reflection is performed from all of the window portions 240 (the first line segment 211, the sixth line segment 216, the eleventh line segment 221 and the window portion 240 on the sixteenth line segment 226) arranged on a straight line. Light will be observed. As a result, the visibility becomes high for the user, so that the alignment can be performed with higher accuracy.

  Furthermore, according to the present embodiment, the alignment portions 22 and 32 have a concentric shape, so that the visibility by the user is higher than in the conventional case having a simple cross shape. When the photomask 2 and the wafer 3 are roughly adjusted, alignment can be easily performed.

  In the present embodiment, the window 240 and the reflector 340 are provided on the four concentric circles in the alignment portions 22 and 32. However, the window 240 and the reflector 340 are provided on at least two concentric circles. Thus, an equivalent effect can be obtained.

  In the present embodiment, in the alignment portions 22 and 32, five moving radii are provided for each of the four directions of the positive and negative directions in the X direction and the Y direction. Although the window portion 240 and the reflection portion 340 are arranged in the vicinity, the number of moving diameters is not limited to five, and an equivalent effect can be obtained by providing an odd number of at least three or more.

  In the present embodiment, the position of the stage 1 is adjusted by checking the reflected light from the reflecting part 340 that passes through the window part 240 with the naked eye. A light amount detection device may be provided to detect the amount of reflected light. In this case, an actuator that moves the stage 1 in the X direction and the Y direction may be further provided so that the stage 1 is automatically moved so that the amount of light is maximized. Thereby, alignment can be performed automatically.

  Further, in this embodiment, when coarse adjustment and fine adjustment are performed, the case where adjustment is first performed from the X direction has been described as an example. However, the order can be set freely from either the X direction or the Y direction as appropriate. Can do.

  In the present embodiment, for example, at the time of fine adjustment in the X direction, the intersection of the sixth to tenth line segments 216 to 220 of the alignment unit 22 and the second to fourth circles 202 to 204 or the intersection thereof Although the case where attention is paid to the window portion group including the window portions 240 formed in the vicinity has been described as an example, in addition to the window portion group, the 16th to 20th line segments 226 to 230 of the alignment portion 22 and the second portion. A window group composed of window sections 240 formed at or near the intersection points of the fourth circles 202 to 204 may also be noted. Similarly, at the time of fine adjustment in the Y direction, a window formed at or near the intersection of the first to fifth line segments 211 to 215 of the alignment unit 22 and the second to fourth circles 202 to 204 Although the case where attention is paid to the window group consisting of the portion 240 has been described as an example, the 11th to 15th line segments 221 to 225 and the second to fourth circles 202 of the alignment unit 22 in addition to the window portion group. A window group composed of the window sections 240 formed at or near the intersections of ˜204 may also be noted. By doing so, a change in the amount of light detected from the window 240 can be detected more sensitively, and as a result, the position of the stage 1 is more easily adjusted to a position where the amount of reflected light is maximized. can do.

  The present invention can be applied to various methods and apparatuses for aligning two members as in an exposure apparatus.

It is a figure which shows typically the principal part structure of the exposure apparatus which uses the position alignment method which concerns on this invention. It is a figure which shows the structure of a photomask typically. It is a figure which shows the structure of a wafer typically. It is a figure which shows typically the structure of the position alignment part of a photomask. It is a figure which shows typically the principal part of the alignment part of a photomask. It is a figure which shows typically the structure of the position alignment part of a wafer. It is a figure which shows typically the principal part of the position alignment part of a wafer. It is a figure which shows typically the state with which the photomask and the part of the alignment part of a wafer overlapped.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Stage, 2 ... Photomask, 3 ... Wafer, 11 ... Mounting surface, 21 ... Pattern, 22 ... Positioning part, 31 ... Pattern, 32 ... Positioning part, 33 ... Orientation flat, 200 ... Center, 201-204 ... 1st-4th circle, 211-230 ... 1st-20th line segment, 240 ... window part, 300 ... center, 301-304 ... 1st-4th circle, 311-330 ... 1st-1st 20 line segments, 340 ... reflection part.

Claims (6)

Based on the first mark formed on the photomask and the second mark formed on the wafer, the photomask and the wafer optically arranged in parallel to the photomask are relatively translated. An alignment method for aligning the photomask and the wafer by:
The first mark includes a window that transmits light,
The second mark constitutes a reflection part that reflects light,
The first mark and the second mark are formed in a rectangular shape having diagonal lines parallel to the moving direction of the photomask and the wafer ,
An alignment method comprising aligning the photomask and the wafer on the basis of the amount of reflected light reflected by the second mark and transmitted through the first mark. The alignment method according to claim 1, wherein a plurality of the first marks and the second marks are formed. The alignment method according to claim 2, wherein the first mark and the second mark are formed on a straight line. The alignment method according to claim 3, wherein the first mark and the second mark are formed on a circumference of a concentric circle.   5. A photomask used in the alignment method according to claim 1, wherein the photomask includes the first mark. 6.   A wafer used for the alignment method according to claim 1, wherein the wafer is provided with the second mark.

Images