JP2001022099A - Exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the execution of exposure with high accuracy in the exposure of a multilayered substrate. SOLUTION: This exposure device irradiates a copper foil mark mask mark E with an X-ray from a lower side by an X-ray tube bulb 2 and picks up the image of the copper foil mark R by an X-ray CCD camera 3. The image of the mask mark E of the mask M is picked up by a visible light CCD camera 4 and is subjected to image processing by an image processing device 7. The alignment of the multilayered substrate K and the mask M is executed by driving a stage 9 in such a manner as to align the centers of the copper foil mark R and the mask mark E. The surface of the conductive layer C of the multilayered substrate K is printed with the circuit patterns of the mask M by the exposure from an exposure light source L when the alignment ends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an exposure apparatus.

[0002]

2. Description of the Related Art In recent years, as products have become lighter, thinner, shorter, smaller, and more sophisticated, as represented by mobile phones, printed circuit boards have been ever-increasing in definition. In particular, for the purpose of increasing the number of electronic components mounted on a substrate, a substrate called a build-up method, which eliminates a hole formed on the entire surface of the substrate conventionally called a through hole, has begun to appear on the market. As shown in FIG. 3, this is a method in which a resin insulating layer and a copper pattern are alternately and sequentially formed on and under an inner layer plate called a core substrate. Since conduction between layers is performed at the time of copper plating, a hole on the substrate surface is formed. Will be equal to nothing. Here, when forming the pattern of the buildup layer formed above and below the core substrate,
To ensure the mutual positional relationship between the formed pattern on the core substrate and the pattern on the buildup layer, it is necessary to align the alignment mark on the core substrate with the alignment mark provided on the photomask for the buildup layer. is there. However, before the pattern of the build-up layer is formed, the entire surface is covered with copper foil, and the alignment marks on the core substrate are not normally visible.

[0003]

Conventionally, in order to make the above-mentioned alignment marks on the substrate readable, when plating the build-up layer, a portion corresponding to the mark on the core substrate is not plated. Then, a method such as peeling off after plating with a mask with a tape or the like is adopted. Alternatively, as another method, there is a method in which holes are used as marks on a core substrate without using a pattern. In this method, when applying the resin insulation layer of the build-up layer, it is necessary to prevent the resin from entering the core substrate or remove the resin that entered the core substrate so that the hole is not covered during the next plating. In any case, the processing is troublesome and is a bottleneck in improving the efficiency of the processing step. An object of the present invention is to solve the above-mentioned problems of the prior art.

[0004]

In order to achieve the above object, the present invention relates to an exposure apparatus for a multi-layer substrate, wherein an insulating layer and a conductive layer having a conductive pattern are alternately formed on the substrate. And a mark provided on at least one of the layers, and an optical system for reading the mark through another layer. Even if the mark is covered with another layer by the above configuration, the mark can be read by an optical system that can read through the layer. Therefore, the mark can be used for alignment between the mask and the multilayer substrate. Further, the present invention provides an exposure apparatus for a multi-layer substrate in which an insulating layer and a conductive layer on which a conductive pattern is drawn are alternately formed on a substrate, wherein a substrate alignment mark for alignment provided on at least one layer of the multi-layer substrate is provided. An X-ray optical system for reading the substrate alignment mark through another layer, and visible light optics for reading a mask alignment mark drawn on a mask on which a pattern to be exposed on the multilayer substrate is drawn. System, and information on the substrate alignment mark from the X-ray optical system, and an alignment device that performs alignment between the mask and the multilayer substrate based on information on the mask alignment mark from the visible light optical system,
It is characterized by having. The substrate alignment mark is read by the X-ray optical system, the mask alignment mark is read by the visible light optical system, and the alignment between the substrate and the mask is performed by the positioning device based on the information. In a preferred embodiment, the X-ray optical system includes a light source device that irradiates at least the substrate alignment mark portion with X-rays from one surface side of the multilayer substrate, and a substrate alignment mark by the X-rays from another surface side. An X-ray imaging device for imaging. Further, the visible light optical system has a visible light imaging device for imaging the mask alignment mark. If the positional relationship between the X-ray imaging device and the visible light imaging device is known, the alignment between the substrate alignment mark and the mask alignment mark can be performed by image processing. In addition, if the optical axes of the X-ray imaging device and the visible light imaging device are aligned, the position can be more easily adjusted by image processing.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the stage 9 is XYZ
The multi-layer substrate K mounted on the stage 9 can be moved to perform alignment with the mask M. . FIG. 1 is a diagram showing only the left half, and the same configuration is also provided on the right side, but is omitted in the figure.

[0006] As shown in FIG.
A conductive layer C1 is formed on the substrate, and an insulating resin layer I is further formed thereon.
1 and a conductive layer C2 is formed thereon. The conductive layer C-1 is formed on the back surface of the core substrate S.
The number of these layers is arbitrary, and a multilayer may be formed on both the front and back surfaces of the core substrate S.

After copper plating is performed on the insulating resin layer I, the pattern of the mask M is exposed by exposure from an exposure light source L by this exposure apparatus, and a circuit pattern is formed by photoetching in a later step. It is configured to be a conductive layer C. Then, an insulating resin layer I is further formed on the conductive layer C, and a similar process is repeated to form a multilayer substrate K. The conductive layers C are electrically connected by via holes, but the via holes are omitted in the drawing.

At the end of the core substrate S, a copper foil mark R as a substrate alignment mark is formed. The mask M is formed by the copper foil mark R and the mask mark E on the mask M.
And the multilayer substrate K is aligned.

An X-ray power source 1 and an X-ray tube 2 are installed below the stage 9 so that the X-rays are irradiated on the copper foil mark R on the core substrate S through the through hole 90 of the stage 9. Have been. An X-ray CCD camera 3 is provided above the core substrate S and the mask M at a position substantially facing the X-ray tube 2, and is configured to project the copper foil mark R.

The mask mark E on the mask M is projected by the visible light CCD camera 4 via the half mirror 5. The ring illumination 6 is a ring-shaped illumination, which illuminates the mask mark E and converts the reflected light into visible light C.
It is configured to allow the CD camera 4 to read.

The image signals of the X-ray CCD camera 3 and the visible light CCD camera 4 are image-processed in an image processing device 7,
The stage 9 is driven by the alignment device 8 based on the image-processed image signal so that the centers of the copper foil mark R and the mask mark E coincide with each other, so that the multilayer substrate K and the mask M are aligned. It is configured. The positioning by the positioning device 8 may be performed automatically, or may be performed manually while the operator views the image from the image processing device 7.

An X-ray CCD camera 3 and a visible light CCD
The position of the camera 4 is a position where the optical axes coincide, and this positional relationship is physically fixed so that the X-ray CCD camera 3 and the visible light CCD camera 4 can move together. At least the positional relationship between the positions of the X-ray CCD camera 3 and the visible light CCD camera 4 needs to be known. If the optical axes do not match, the image processing device 7 or the alignment device is determined based on the known positional relationship. 8 needs to be corrected.

In the structure described above, when the pattern drawn on the mask M on the conductive layer C2 is exposed, the X-ray tube 2 transmits through the insulating resin layer I1 and the conductive layer C2 and passes through the half mirror 5. The incoming X-ray is received by the X-ray CCD camera 3 to image the copper foil mark R. At the same time, an image of the mask mark E on the mask M reflected by the half mirror 5 is picked up by the visible light CCD camera 4. The images of the copper foil mark R and the mask mark E are image-processed by the image processing device 7, and the stage 9 is controlled and adjusted by the positioning device 8 so that the centers of the copper foil mark R and the mask mark E coincide with each other.
The multilayer substrate K moves. When the positioning is completed, the X-ray CCD camera 3, the visible light CCD camera 4, the half mirror 5 and the ring illumination 6 are retracted to predetermined positions, and then the stage 9 is moved in the direction of the mask M, and the mask M and the multilayer The substrate K is brought close to the exposure light source L at a predetermined position.
And the pattern on the mask M is printed on the conductive layer C2. By the above operation, accurate positioning can be performed, and as a result, exposure with high precision can be performed.

In the above embodiment, the case where the multilayer substrate K is moved has been described. However, a configuration in which the mask M is moved is also possible. Further, both the mask M and the multilayer substrate K may be moved. In the embodiment shown in FIG. 1, copper plating exists at the position of the conductive layer C2 corresponding to the position of the copper foil mark R. However, when the conductive layer C has a multilayer structure, it is necessary to remove the copper plating by etching. It is desirable to accurately capture the image of the foil mark R.

In the above embodiment, the case where the position of the mask M is aligned with the copper foil mark R of the core substrate S has been described. However, the position may be aligned with the lower conductive layer C. For example, as shown in FIG. 2, when the pattern is exposed on the conductive layer C3, the copper foil mark R is used instead of the copper foil mark R1.
2 may be used for positioning. In such a case, the copper foil mark R1 and the copper foil mark R
It is desirable to form them at a shifted position. This is the same when, for example, forming the copper foil mark R on the front and back of the core substrate S, and it is desirable to shift the position on the front and back.

As described above, according to the above-described embodiment, the images of the copper foil mark R and the mask mark E can be accurately taken at the time of pattern exposure of the multilayer substrate K.
And the mask M can be aligned with high accuracy, and as a result, exposure with high accuracy can be obtained.

[0017]

As described above, according to the exposure apparatus of the present invention, highly accurate positioning can be performed when exposing the multilayer substrate K, and as a result, exposure can be performed with high accuracy.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing an example of an embodiment of forming a copper foil mark R according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a method of forming a multilayer substrate K.

[Explanation of symbols]

1: X-ray power supply, 2: X-ray tube, 3: X-ray CCD camera, 4: visible light CCD camera, 5: half mirror, 6:
Ring illumination, 7: image processing device, 8: alignment device,
9: Stage, 90: Through-hole.

Continuing from the front page (72) Inventor Wataru Nakagawa 3-4-30 Shiba-koen, Minato-ku, Tokyo F-term in Adtech Engineering Co., Ltd. (Reference) 2H097 CA15 GA45 KA05 KA12 KA13 KA20 KA28 LA09 5F046 AA04 AA26 BA02 EA04 EB01 EB02 ED01 FA01 FA08 FA10 FC04 FC07

Claims (3)

[Claims] 1. An exposure apparatus for a multi-layer substrate in which an insulating layer and a conductive layer having a conductive pattern drawn thereon are alternately formed on a substrate, wherein a mark provided on at least one layer of the multi-layer substrate and another mark are provided. An exposure system comprising: an optical system for reading through a layer. 2. An exposure apparatus for a multi-layer substrate in which an insulating layer and a conductive layer having a conductive pattern drawn thereon are alternately formed on a substrate, wherein a substrate alignment mark for positioning is provided on at least one layer of the multi-layer substrate. An X-ray optical system for reading the substrate alignment mark through another layer; and a visible light optics for reading a mask alignment mark drawn on a mask on which a pattern to be exposed on the multilayer substrate is drawn. And a positioning device for performing positioning of a mask and a multilayer substrate based on information of a substrate alignment mark from the X-ray optical system and information of a mask alignment mark from the visible light optical system. Exposure apparatus characterized by the above-mentioned. 3. A light source device for irradiating at least the substrate alignment mark portion from one surface side of the multilayer substrate with the X-ray optical system, and imaging the substrate alignment mark with the X-rays from the other surface side. An X-ray imaging device; wherein the visible light optical system has a visible light imaging device for imaging the mask alignment mark; and a positional relationship between the X-ray imaging device and the visible light imaging device is known. Item 3. An exposure apparatus according to Item 2.