JP3180004B2 - Exposure film alignment method and alignment apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for aligning a pair of exposure films for transferring a pattern on both sides of a substrate.

[0002]

2. Description of the Related Art In a so-called double-sided printed circuit board in which patterns (circuit patterns) are formed on both front and back sides, for example,
Photosensitive dry film resist is stuck on the front and back surfaces of a substrate consisting of a double-sided copper-clad laminate, and a transfer exposure film on which a pattern is drawn is placed on top of each other. Then, a method of transferring the pattern of the exposure film to both the front and back surfaces of the substrate by exposing the resist to light is adopted.

Since the patterns on both the front and back surfaces of the substrate need to be aligned with each other, before transferring the pattern to the substrate using an exposure apparatus, it is necessary to dispose the substrate between the two exposure films. The positions of the patterns on both exposure films are matched. Such alignment of the pattern positions of the pair of exposure films may be performed using an alignment mechanism provided in the exposure apparatus itself, or may be performed using an alignment apparatus that aligns the exposure film separately from the exposure apparatus. .

Each exposure film is fixed to a colorless and transparent plate such as an acrylic plate or a glass plate with an adhesive tape, or, when the plate is an acrylic plate, is attached to a suction groove formed in the plate. The plate is sucked, sucked and fixed, and each plate is supported by a frame. As for a pair of frames supporting the plate, one frame (fixed frame) is fixed and the other frame (movable frame) is movable.

On the other hand, the aligning device includes moving means for moving the moving frame in a plane substantially parallel to the plate along the x-axis and y-axis orthogonal coordinate axes, and rotating means for rotating the moving frame in the plane. When,
A pair of CCD cameras for capturing alignment marks of each exposure film, which will be described later, and a moving frame necessary for capturing images captured by these CCD cameras and aligning the alignment marks of both exposure films from the captured images. A calculation control means for determining the amount of movement and the amount of rotation and the respective directions is provided.

In the above-mentioned conventional aligning apparatus, since the positions of the respective patterns cannot be directly aligned when the substrate is disposed between the two exposure films, the patterns of the pair of exposure films as shown in FIG. Alignment mark 9a composed of a black circle of φ2 at a diagonal position of the periphery around the portion where the circle is formed, and a donut-shaped alignment mark 9 having a white circle of φ2 at the center of the black circle of φ5
b, and each alignment mark 9a, 9a,
9b is imaged, and the arithmetic and control means obtains the amount of movement and the amount of rotation required to superimpose the alignment mark 9b on the outline of the alignment mark 9b and their respective directions,
Further, the moving means and the rotating means are controlled by the arithmetic and control means, and the moving frame is moved and rotated in the respective directions of the determined moving amount and the rotating amount, thereby indirectly exposing the two exposure films 1a and 1b. The position of the pattern is consistent. There is an exposure apparatus having a pattern matching function and mechanism using such alignment marks 9a and 9b.

[0007]

In the above-mentioned conventional alignment method and alignment apparatus, it is possible to obtain a sufficient accuracy in alignment of the positions of the alignment marks 9a and 9b of the exposure films 1a and 1b, The alignment accuracy of the pattern positions of the exposure films 1a and 1b depends on the positional accuracy when the alignment marks 9a and 9b are provided on the exposure films 1a and 1b, and the alignment marks 9a and 9b and the patterns correspond to the exposure films 1a and 1b. Are formed separately and independently from each other, the position accuracy of the alignment marks 9a and 9b with respect to the pattern cannot be sufficiently secured, and as a result, the positions of the patterns of the exposure films 1a and 1b cannot be accurately aligned. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an exposure film alignment method and an alignment method capable of accurately aligning the positions of the patterns of each exposure film on both front and rear surfaces. It is to provide a device.

[0009]

According to a first aspect of the present invention, there is provided an exposure film aligning method for aligning positions of a pair of exposure films for transferring a pattern to both front and back surfaces of a substrate. A plurality of reference marks provided in the pattern of each exposure film are aligned without disposing a substrate between both exposure films, and provided outside the pattern of each exposure film in a state where the reference marks are aligned. After measuring the amount of misalignment between the plurality of alignment marks, and once aligning the alignment marks of both exposure films with the substrate disposed between the two exposure films, the reference marks of both exposure films are compared based on the amount of misalignment. , The relative position of each exposure film is corrected so as to match.

According to a second aspect of the present invention, there is provided an exposure film aligning apparatus for aligning the positions of a pair of exposure films for transferring a pattern on both front and back surfaces of a substrate. A plurality of reference marks are provided in the pattern of the film and a plurality of alignment marks are provided outside the pattern, and at least one of the exposure films is movably and rotatably held in a plane substantially parallel to the pattern surface, so that both the exposure films are formed. Displacement means for displacing the relative position, imaging means for imaging the reference mark and the alignment mark from a direction substantially orthogonal to the pattern surface of the exposure film, and reference marks for both exposure films based on the image taken by the imaging means; Control means for determining the amount of displacement such that the alignment marks are aligned with each other and controlling the displacement means. Is based on the amount of displacement required to align the alignment marks when the reference marks are aligned without the substrate between the two exposure films, and the alignment marks are aligned by positioning the substrate between the two exposure films It is characterized in that the relative position of both exposure films is displaced by controlling the displacement means from the state in which the exposure films are made.

[0011]

According to the first aspect of the present invention, a plurality of reference marks provided in the pattern of each exposure film are aligned without disposing a substrate between the two exposure films, and the reference marks are aligned. After measuring the amount of misalignment between a plurality of alignment marks provided outside the pattern of each exposure film, and once aligning the alignment marks of both exposure films with the substrate disposed between the two exposure films, based on the amount of misalignment described above. Since the relative position of each exposure film is corrected so that the reference marks of both exposure films are aligned with each other, the front and back of the substrate generated when the alignment marks provided outside the patterns of both exposure films are aligned The misalignment of the pattern of the exposure film with respect to both sides is determined based on the fiducial mark that has high positional accuracy with respect to the pattern because it is provided in the pattern There are can be corrected, the position of the pattern of the exposed film for both surfaces of the substrate can provide a consistent method for accurately alignable exposed film.

According to a second aspect of the present invention, a plurality of reference marks are provided in the pattern of each exposure film, and a plurality of alignment marks are provided outside the pattern, so that at least one of the exposure films is placed in a plane substantially parallel to the pattern surface. Displacing means for displacing the relative positions of the two exposure films while holding them movably and rotatably, imaging means for imaging fiducial marks and alignment marks from a direction substantially perpendicular to the pattern surface of the exposure film, and imaging means Control means for determining a displacement amount such that the reference marks or alignment marks of both exposure films are aligned based on the captured image of the both exposure films and controlling the displacement means, wherein the control means arranges the substrate between the two exposure films. Based on the amount of displacement required to align the alignment marks when the fiducial marks are aligned without Since the relative position of the two exposure films is displaced by controlling the displacement means from the state where the alignment marks are aligned with the substrate arranged between the exposure films, the alignment provided outside the patterns of the two exposure films The misalignment of the pattern of the exposure film with respect to the front and back surfaces of the substrate caused when the marks are aligned,
An exposure film alignment device that can be corrected based on a reference mark that has a high positional accuracy with respect to the pattern because it is provided in the pattern, and that can accurately align the position of each exposure film pattern with respect to the front and back surfaces of the substrate. Can be provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic block diagram showing a matching device according to the present embodiment. As in the conventional example, a movable frame 3 for supporting a plate 2 made of a colorless and transparent acrylic plate to which a pair of exposure films 1a and 1b are fixed, and a fixing frame. The frame 4 and the moving frame 3 are moved along the x-axis and the y-axis orthogonal coordinate axes in a plane substantially parallel to the plate body 2, and the moving frame 3 is rotated in the plane to move the moving frame 3 with respect to the fixed frame 4. A displacement mechanism 5 for displacing the relative position of the moving frame 3 and a pair of Cs for imaging the exposure films 1a and 1b from a direction substantially orthogonal to the plate 2 of the moving frame 3;
CD cameras 6 ₁ and 6 ₂ , a light source 7 for illuminating the exposure films 1 a and 1 b from the side of the fixed frame 4, and a displacement mechanism 5 based on images taken from the CCD cameras 6 ₁ and 6 ₂
And a control unit 8 that controls the position of the moving frame 3 by controlling the position of the moving frame 3.

Although the detailed structure and illustration of the displacement mechanism unit 5 are omitted, the displacement mechanism unit 5 has a well-known structure used in a conventional alignment device and exposure device, and is arranged on the x-axis and the y-axis of a rectangular coordinate system. The moving frame 3 can be moved along,
The moving frame 3 can be rotated around a certain point as a reference point. The control section 8 includes a microcomputer, and has CCD cameras 6 ₁ and 6 _2.
Coordinates (x, y) of an arbitrary point in the image taken from
The angle θ of the point with respect to the orthogonal coordinate axis (x-axis or y-axis) is obtained, and the coordinates and angles of a plurality of points are subjected to arithmetic processing such as four arithmetic operations and primary conversion.

[0015] As shown in FIG.
Although a pair of alignment marks 9a and 9b are provided on each of the reference marks 10a and 10b in the pattern of the exposure films 1a and 1b, the reference marks 10a and 10b are provided in the present embodiment. Is provided. These reference marks 10a and 10b are originally used as a reference for positioning at the time of perforation after the pattern is transferred to the substrate. The shape of the reference marks 10a and 10b may be any shape as long as it is easy to determine the degree of overlap between them.
Even if it is a simple black circle, the alignment marks 9a and 9b
It may have the same shape as.

Next, the exposure film 1 in this embodiment
The matching method of a and 1b will be described. First, moving frame 3
After fixing each of the exposure films 1a and 1b to the plate 2 of the fixed frame 4 by the method described in the conventional example, the two are brought close to each other without disposing the substrate between the moving frame 3 and the fixed frame 4. In this situation, the moving frame 3 is moved and rotated by the displacement mechanism unit 5 to displace the relative position of the moving frame 3 with respect to the fixed frame 4, so that the exposure films 1a and 1b are exposed as shown in FIG.
The reference marks 10a and 10b provided at the same location are aligned with each other. Note that such reference marks 10a, 1
The alignment of the displacement mechanisms 5b is performed by appropriately displaying images from the CCD cameras 6 ₁ and 6 _{2 on} a display device or the like.
Is performed visually while operating manually, or alignment marks 9a and 9b in a conventional alignment device are used.
May be automatically performed in the same manner as in the case of the matching. Here, in a state where the reference marks 10a and 10b are aligned with each other, as shown in FIG. 3, the respective alignment marks 9a and 9b of the exposure films 1a and 1b are displaced due to positional accuracy with respect to the pattern. On the other hand, as shown in FIG. 2, the reference marks 10a and 10b
1b, for example, CAD
Since the pattern can be formed in the pattern at the same time as designing the pattern using the system, the reference marks 10a,
The positional accuracy for the pattern 10b is so high that it cannot be compared with those of the alignment marks 9a and 9b. Accordingly, the accuracy of the alignment of the pattern positions of the exposure films 1a and 1b in the state where the reference marks 10a and 10b are aligned as described above is extremely high.

Next, in the control unit 8, each alignment mark 9 of both exposure films 1a and 1b in the above state is
The orthogonal coordinates A, B, C, and D of a and 9b and the vertical dimension of the portion where the pattern is drawn (the size corresponding to the vertical size of the substrate) are obtained, and the vertical size of the portion where the pattern is drawn is obtained. Thus, the rectangular coordinate system in which the rectangular coordinates A, B, C, and D are obtained is shift-converted to the rectangular coordinate system in the moving frame 3 centered on the reference point of the rotation as shown in FIG. Here, the drawing position of the pattern on the exposure films 1a and 1b changes according to the size of the drawing range of the pattern. The fixed position of the exposure films 1a and 1b with respect to the moving frame 3 and the fixed frame 4 is also changed. There is variation. Moreover, as shown in FIGS. 5A and 5B, the exposure films 1a,
Depiction position of the pattern relative 1b, since it is based on the one side of the rectangular pattern delineation range M _1, M _2, M _3, depicting a range of patterns M _1, M _2, M ₃ dimensions (the dimensions of the substrate) The pattern description range M ₁ , M ₂ , M
The center of ₃ does not always coincide with the centers of the exposure films 1a and 1b. Thus, as described above, the dimensions of the pattern description ranges M ₁ , M ₂ , and M ₃ (the dimensions of the substrate) are obtained, and the rectangular coordinate system is shifted to the rectangular coordinate system of the moving frame 3 so as to obtain the difference in the substrate dimensions. Alignment marks 9a, 9b in the orthogonal coordinate system of the moving frame 3 (orthogonal coordinate system centered on the rotation center of the moving frame 3) regardless of
And the orthogonal coordinates of the reference marks 10a and 10b can be obtained. All the rectangular coordinates in the following description are in the rectangular coordinate system of the moving frame 3.

Next, as shown in FIG.
a, the coordinates A of the alignment marks 9a, 9b of 1b,
From B, C, and D, the midpoint P ₁ (x _P1 , y _P1 ) of the line segment AB, the angle θ ₁ between the x axis and the line segment AB, and the mid point P _{2 of the} line segment CD
(X _P2 , y _P2 ) and the angle θ ₂ between the x axis and the line segment CD are obtained by the control unit 8, and further, the angle θ ₀ (= θ ₂ −θ ₁ ) formed by the two line segments AB and CD is obtained. calculate. Then, the midpoint P ₂ (x _P2 , y) of the line segment CD is obtained by the primary conversion represented by the following equation.
Point and the _P2) is rotated by theta ₀ around the origin Q ₂ (x _q2,
y _q2 ).

[0019]

(Equation 1)

Then, the obtained point Q _{2 is set} to the midpoint P of the line segment CD.
_The amount of parallel movement (Δx, Δy) that matches with ₂ is represented by Δ
x = x _P2 −x _q2 , Δy = y _P2 −y _q2 Therefore, if the control unit 8 outputs control signals for the movement amounts Δx and Δy and the rotation amount Δθ (= θ ₀ ) with respect to the displacement mechanism unit 5 to displace the relative position of the moving frame 3, As shown in FIG. 6, the alignment marks 9a and 9b of the exposure films 1a and 1b can be aligned. In other words, the alignment marks 9 on both exposure films 1a and 1b
In the state where a and 9b are matched, the movement amounts Δx and Δy
And the corrected movement amount (−Δ
(x, -Δy) and the correction rotation amount (-Δθ), the reference marks 10a, 10b of both exposure films 1a, 1b can be automatically aligned.

That is, as in the prior art, a substrate is disposed between the movable frame 3 on which the exposure films 1a and 1b are fixed and the fixed frame 4, respectively, and the movable frame 3 is moved relative to the fixed frame 4 as shown in FIG. And then temporarily shift both exposure films 1
After the alignment marks 9a and 9b are aligned with each other, the position of the moving frame 3 is displaced by the correction movement amount and the correction rotation amount, and the substrate is disposed between the exposure films 1a and 1b. Thus, the reference marks 10a and 10b are aligned with each other, and as a result, as shown in FIG. 3, the positions of the patterns of the exposure films 1a and 1b can be aligned with high accuracy. If the moving frame 3, the fixed frame 4 and the substrate are conveyed and exposed to the exposure unit of the exposure apparatus while maintaining the state in which the reference marks 10a and 10b are aligned, position alignment can be performed with high precision. The peeled pattern can be transferred to both sides of the substrate. Or,
The light source for exposure or the like may be moved in the above-mentioned alignment state, and the light source and the like may be arranged so as to face the movable frame 3 and the fixed frame 4 to perform exposure.

In this embodiment, the case where the aligning device is separate from the exposure device has been described. However, even when the aligning device (or the aligning function) is added to the exposure device, the technical features of the present invention can be improved. It goes without saying that ideas can be applied.

[0023]

According to the first aspect of the present invention, there is provided an exposure film aligning method for aligning a pair of exposure films for transferring a pattern on both sides of a substrate, wherein the substrate is disposed between the two exposure films. Without aligning multiple reference marks provided in the pattern of each exposure film, measure the amount of misalignment between multiple alignment marks provided outside the pattern of each exposure film while the reference marks are aligned. After aligning the alignment marks of the two exposure films once with the substrate disposed between the two exposure films, the relative positions of the respective exposure films are adjusted so that the reference marks of the two exposure films are aligned based on the amount of deviation. The position of the alignment marks provided outside the patterns on both exposure films. The positional deviation of the pattern of the optical film can be corrected based on a reference mark having a high positional accuracy with respect to the pattern because it is provided in the pattern, and the position of the pattern of each exposure film with respect to both the front and back surfaces of the substrate can be accurately determined. There is an effect that an alignable exposure film alignment method can be provided.

According to a second aspect of the present invention, there is provided an exposure film aligning apparatus for aligning the positions of a pair of exposure films for transferring a pattern on both front and rear surfaces of a substrate, wherein a plurality of reference films are included in each exposure film pattern. A mark is provided and a plurality of alignment marks are provided outside the pattern, and at least one of the exposure films is moved and rotated freely in a plane substantially parallel to the pattern surface to displace the relative positions of the two exposure films. Means, an imaging means for imaging the reference mark and the alignment mark from a direction substantially perpendicular to the pattern surface of the exposure film, and a method for aligning the reference marks or the alignment marks of both exposure films based on the image taken by the imaging means. Control means for determining the displacement amount and controlling the displacement means, wherein the control means controls the distance between the two exposure films. Based on the amount of displacement required to align the alignment marks when the reference marks are aligned with no alignment marks, the displacement means is controlled from the state where the substrate is positioned between the two exposure films and the alignment marks are aligned. Since the relative positions of the two exposure films are displaced, the misalignment of the pattern of the exposure film with respect to the front and back surfaces of the substrate caused when the alignment marks provided outside the patterns of the two exposure films are aligned. , An exposure film alignment device that can be corrected based on a fiducial mark having a high positional accuracy with respect to the pattern because it is provided in the pattern, and that can accurately align the position of each exposure film pattern with respect to the front and back surfaces of the substrate. There is an effect that can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing one embodiment of the present invention.

FIGS. 2A and 2B are plan views showing the exposure film in the above.

FIG. 3 is an explanatory diagram for explaining the operation of the above.

FIG. 4 is an explanatory diagram for explaining the operation of the above.

FIG. 5 is an explanatory diagram for explaining the operation of the above.

FIG. 6 is an explanatory diagram for explaining the operation of the above.

FIG. 7 is an explanatory diagram for explaining the above operation.

[Explanation of symbols]

1a, 1b exposed film 2 plate body 3 moving frame 4 fixed frame 5 displacement adjusting mechanism 6 _1, 6 ₂ CCD camera 7 light source 8 controller 9a, 9b alignment marks 10a, 10b the reference mark

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F ^7/ 20-7/24 G03F 9/00-9/02 H01L 21/027

Claims (2)

(57) [Claims] An exposure film alignment method for aligning the positions of a pair of exposure films for transferring a pattern to both front and back surfaces of a substrate, wherein each exposure film is disposed without disposing the substrate between the two exposure films. A plurality of reference marks provided in the pattern are aligned with each other, and the amount of displacement between the plurality of alignment marks provided outside the pattern of each exposure film is measured in a state where the reference marks are aligned. After aligning the alignment marks of both exposure films once in a state where is arranged, it is necessary to correct the relative positions of the respective exposure films based on the above-mentioned shift amounts so that the reference marks of both exposure films are aligned. Characteristic exposure film alignment method. 2. An exposure film aligning apparatus for aligning positions of a pair of exposure films for transferring a pattern on both front and back surfaces of a substrate, wherein a plurality of reference marks are provided in the pattern of each exposure film. A plurality of alignment marks provided outside, a displacing means for displacing a relative position of the two exposure films by holding at least one of the exposure films movably and rotatably in a plane substantially parallel to the pattern surface, and an exposure film Imaging means for imaging the reference mark and the alignment mark from a direction substantially orthogonal to the pattern surface of the exposure film; and obtaining a displacement amount such that the reference marks or the alignment marks of both exposure films are aligned based on the image taken by the imaging means. Control means for controlling the displacement means, wherein the control means does not arrange the substrate between the two exposure films. Based on the amount of displacement required to align the alignment marks when the reference marks are aligned with each other, the displacement means is controlled from the state where the alignment marks are aligned by positioning the substrate between the two exposure films. An exposure film aligning apparatus characterized by displacing a relative position of a film.