KR100381673B1 - Multilayer printed circuit board and method for measuring a gap between the layers - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed circuit board and a method for measuring the gap between layers thereof, wherein the amount of deformation of each conductor layer of the inner layer of the multilayer printed circuit board is observed and recorded.

A solid guide mark 22 and a hollow guide mark 23 are formed in the inner and outer conductor layers of the inner double-sided circuit board 61 of the multilayer printed circuit board 60. For example, the hollow guide marks 23-2a formed in the adjacent conductor layers are arranged concentrically on the solid guide marks 22-1b, and the solid and hollow guide marks 22, 23 are arranged concentrically for each adjacent conductor layer. ). A set of solid, hollow guide marks 22 (1a to 5a) and 23 (1b to 5b), which are concentric in three rows and three columns, are arranged in the guide mark frame 21, which is an external shape that enters the field of view of the X-ray camera. do. The guide mark group 20 is arranged at four corners of the multilayer printed circuit board, for example, and one guide mark group acquires the entire guide mark in the frame by one X-ray irradiation. The coordinate value is calculated. The deformation amount of the wiring pattern formed in each conductor layer can be calculated from the coordinate value of the guide mark in four guide mark groups, and a result can be recorded.

Description

MULTILAYER PRINTED CIRCUIT BOARD AND METHOD FOR MEASURING A GAP BETWEEN THE LAYERS}

The present invention relates to a multilayer printed circuit board having a guide mark formed on a conductor layer capable of identifying the interlayer deviation of each conductor layer of the inner layer with high accuracy, and a measuring method suitable for measuring these guide marks.

In recent years, in addition to miniaturization of surface-mount electronic components such as IC chips, resistors, and capacitors, printed circuit boards on which they are mounted are also required to have high density, and are often multilayered. In general use, multilayer printed circuit boards having 4 or 6 layers of conductor layers are used, and high multilayer printed circuit boards having much more layers are used in industrial applications.

The multilayer printed circuit board is composed of two inner and outer conductor layers exposed to the outside and an inner conductor layer of several layers which are not exposed, and an insulating substrate is inserted between the conductor layers, and the conductor layers are bonded by these substrates. .

As a conductor layer of a multilayer printed circuit board, for example, a copper foil having a thickness of about 18 μm is used.

As substrate materials, thermosetting glass and epoxy resins are mainly used, and heat-resistant resins such as glass, polyimide resins, glass and BT resins are also used for high-layer circuit boards.

Since the multilayer printed circuit board having six or more layers merely has a large number of conductors in the inner layer, the manufacturing method of the six-layer multilayer printed circuit board will be briefly described with reference to FIGS. 10 and 11.

Fig. 10 (a) is a perspective view schematically showing the structure of a six-layer circuit board, and (b) is a plan view schematically showing a printing pattern formed on the conductor portion of the double-sided circuit board serving as an inner layer. (c) shows the side view of the jig board used at the time of the layup mentioned later.

Fig. 11 is a cross-sectional view of a six-layer circuit board, in which (a) shows the state before the hot pressing step, and (b) shows the state of becoming one multilayer substrate by being thermally cured and bonded by the hot pressing.

As shown in FIG. 10 (a), the six-layer multilayer circuit board 60 includes prepregs 64 and 64a between the exposed two-layer conductor layer 62 and two inner printed circuit boards 61 serving as inner layers. ) Is formed.

On the double-sided printed circuit board 61 constituting the inner layer, a single circuit board pattern 61a or the like which is a final product (six in the figure) is usually formed on the inner and outer copper foil surfaces by etching.

At least two positioning guide holes 65 are formed in the double-sided circuit board 61 in advance, and patterns 61a and the like on both sides of the inside and outside are formed on the basis of the guide holes 65. 61) The pattern inside and outside is secured to each other in plan view. Thus, the pattern 61a etc. are formed in the two-sided circuit board 61 using the guide hole 65 of the same coordinate position.

The pattern formed on the double-sided printed circuit board 61 serving as an inner layer substrate includes a guide mark 66 (two center portions) or guide marks 66b (for each reference hole) for the reference hole to be used in a later process in addition to the pattern 61a of the single circuit board. A plurality of guide marks 66a indicating the positions of four or more corners and reference holes for identification inside and outside are prepared, and these guide marks are also formed in the etching process.

A plurality of inner layered double-sided printed circuit boards which have been etched are superimposed to properly align the positional relationship of patterns formed on the conductors of the respective circuit boards.

A jig plate 68 having two pins 68a is prepared. The center distance of the pin 68a is equal to the center distance of the guide hole 65 used when forming the pattern 61a on the double-sided printed circuit board 61.

The one-sided double-sided substrate 61 which has been etched is inserted through the pin 68a of the jig plate 68 into the guide hole 65 and placed on the jig plate 68. The substrate material (prepreg) 64a before heating in which the guide hole 65 was drilled is placed thereon. In addition, the other double-sided board 61 is inserted through the pin 68a of the jig plate 68 into the guide hole 65 and is stacked on the jig plate 68. In this step, the two periphery substrates 61 and the outer circumference of the prepreg 64a therebetween are temporarily fixed to complete the layup.

As shown in the cross-sectional view of Fig. 11 (a), when the prepreg 64 and the copper foil 62, which is a conductor material, are placed on both sides of the laid-up two-sided double-sided printed circuit board 61 and pressurized by a hot press, The prepregs 64 and 64a inserted between the copper foil 62 and the double-sided substrate 61 are thermally cured to change into the (insulated) substrate 63, and the adhesion between the conductors is also completed, as shown in FIG. 11 (b). One multilayer printed circuit board 60 is obtained.

Thereafter, a new reference hole corresponding to the inner layer pattern of the multilayer substrate is drilled, and the outermost conductor circuit pattern is etched, the through hole is drilled, etc. based on the new reference hole.

Here, in order to avoid confusion, a positioning hole used for layup is referred to as a guide hole and a positioning hole used in a process after hot pressing is referred to as a reference hole.

As described above, in the pattern formed on the inner layer substrate, a plurality of guide marks 66 and 66a and the like for the reference hole are prepared in addition to the pattern 61a of the single circuit board, and the guide marks are also etched in the etching process. Since the coordinates of these guide marks are determined to have a certain positional relationship with the pattern 61a of the single circuit board, the coordinates of the patterns constituting the electric circuit are found by measuring the positions of these guide marks.

An X-ray (reference hole) perforator is generally used to drill a new reference hole corresponding to the guide mark 66 formed on the inner layer of the multilayer substrate 60.

As described above, both front and rear outer surfaces of the multilayer substrate pressurized and heated by a hot press are covered with a clean conductor layer, and it is impossible to visually clearly see the guide marks formed on the inner layer using visible light.

Currently, the method of measuring the position of the guide mark formed on the inner layer substrate through the multilayer substrate through weak X-rays is common, but various other ultrasonic methods have been studied. As a result, the guide mark position formed on the inner layer substrate can be collectively measured by using something other than visible light.

Usually, guide marks are formed on any one conductor layer of a set of inner layer substrates laid up. At least two guide marks are formed at positions apart from each other so that the deformation state of the inner layer substrate may be described with a specific numerical value.

In recent years, the number of guide marks tends to increase in order to capture deformations of inner layer substrates, and as shown by reference numeral 66b in FIG. 8, guide marks are formed at four corners of one conductor layer to form a deformation state perpendicular to a plane. Allow measurement in two directions. (For example, FIG. 10 shows an example of four guide marks)

Since the inner layer substrate is slightly deformed because it is pressurized by a hot press at the time of manufacture of the multilayer substrate, the guide marks of the inner layer substrate also differ from the initially set coordinates. The distance between the guide marks is often different from the design value.

However, since the reference hole used in the post-process is inserted and used in the pin installed in the jig plate, it is more practical to make the center distance of the reference hole, that is, the reference hole spacing equal to the pin spacing of the jig plate. As such, the method of drilling the reference hole such that the center distance of the reference hole is a predetermined reference hole spacing is referred to as an intermediate point method. The number of reference holes used at the same time may be arbitrarily selected.

In addition, depending on the nature of the jig plate used in the post-process, the position and the number of the guide marks formed on the inner layer substrate and the reference hole actually drilled are often different. In addition, in the case of two reference holes, an additional one reference hole may be added for identification inside and outside, and a few sets of reference holes may be needed depending on the number of subsequent processes due to fear of wear deformation of the reference hole inserted in the pin of the jig plate. This may be perforated beforehand.

Here, the coordinate system used when designing the pattern of the conductor layer of the multilayer printed circuit board is called a design coordinate system. The coordinate values of the guide marks formed on the conductor layer are shown in this design coordinate system, respectively.

Further, assume a machine coordinate system fixed to a floating part such as a housing of a perforator and having a coordinate axis parallel to the direction of motion of the main component.

When the multilayer printed circuit board is set in the perforator and the guide marks are observed by, for example, an X-ray camera, the coordinate values indicated in the machine coordinate system can be obtained as positions on the perforator of each guide mark. By processing this coordinate value statistically, the coordinates of the coordinate origin of the design coordinate system and the most obvious values of the coordinate axis direction can be converted to the coordinates of the reference hole described in the design coordinate system. If the position of the reference hole is indicated in the machine coordinate system, the reference hole can be drilled by moving the spindle equipped with the reference hole drill to this position.

The reference hole perforator has a built-in calculation means for estimating the element of the design coordinate system from the measured value of the guide mark, and for this reason, various calculation methods have been proposed.

Next, referring to FIG. 12, a function of a two-hole midpoint reference hole drill generally used will be described. As the guide marks, for example, two marked with reference numeral 66 in FIG. 10 are measured, and the distances from the center points equidistant from the two guide marks on a straight line connecting two guide mark centers are equal to each reference hole, and The reference hole is drilled so that the center spacing of the reference hole is a predetermined dimension.

FIG. 12A is a plan view through the housing 71a, and FIG. 12B is a perspective view of the housing 71a as viewed from the operator's side. In FIG. 12A, which shows a plane, the movable stand 80 is divided into two or more, or the X movable stand 73 on the right side is omitted. In addition, as described above, the machine coordinate system 50 is a coordinate system in which the origin Om is fixed to the floating part of the drilling machine, and the coordinate axis is defined in parallel in the main direction of motion of the machine. Set the Ym axis and the Zm axis in the vertical direction.

The linear guide 73a and the ball screw 73b are installed on the mount 72 fixed to the enclosure 71a to support the two channel type X movable mounts 73 to be movable. The X-ray generator 74 is fixed to the uppermost portion of the X movable mount 73, and a linear guide 78a and a ball screw 78b are provided at the lower portion to support the Y movable mount 78 so as to be movable.

The two X-moving mounts 73 move in parallel to the Xm axis of the machine coordinate system in opposite directions, and their spacing varies according to the size of the multilayer printed circuit board to be drilled.

The Y movable stand 7 independently moves parallel to the Ym axis of the machine coordinate system, on which the X-ray camera 76 and the spindle 77, which is a drill rotating mechanism, are fixed at predetermined intervals.

The moving table 80 is disposed in the middle of two X moving stands 73 and moves in parallel to the Ym axis of the machine coordinate system. The multilayer printed circuit board (not shown) is placed on the movable table 80 at the position of 80 A by the linear guide 80a and the ball screw 80b disposed near the center of the movable table, and the movable table (b) in FIG. 80) to the puncture position indicated by

X-rays radiated from the X-ray generator tube 74a embedded in the X-ray generator 74 are not shown through holes drilled in the X-axis protective tube 75 and the clampers 75a arranged to be movable at the ends thereof. The guide mark of the multilayer printed circuit board is transmitted to the X-ray camera 76 below.

Since the position (coordinate value by the machine coordinate system) of the X-ray camera 76 is already known, the coordinates of the guide mark can be known by measuring the position on the screen of the guide mark taken by the X-ray camera 76. The coordinates of the two guide marks can be known from the image of the left and right X-ray cameras 76.

The coordinates H1 (X1, Y1) and H2 (X2, Y2) of the reference hole are calculated from the coordinates of these two guide marks.

The Y-moving mount 78 on which the spindle 77 and the X-ray camera 76 are placed moves in the Ym axis direction, so that the spindle 77 occupies the position where the X-ray camera was located. Since the Y-moving platform 78 on which the spindle is placed can move in the Ym-axis direction and can also move in the X-axis direction, the coordinates H1 (X1, Y1) of the reference hole calculated by performing fine adjustment in the Xm-axis direction and the Ym-axis direction ), And drill the drill 77b under the H2 (X2, Y2).

At this time, the clamper 75a disposed at the lower end of the X-ray protective tube 75 is lowered to press the periphery of the perforated portion of the multilayer printed circuit board to prevent movement of the multilayer printed circuit board during the perforation.

In this way, when the two guide marks 66 are observed and drilled through the reference hole, the deformation state of the multilayer circuit board in the range indicated by the diagonal lines in FIG. 10B is reflected, but the change in the direction perpendicular thereto is ignored.

As described above, in recent years, three or more guide marks 66b are formed at four corners of the inner layer substrate, and the reference holes reflecting the state of deformation of the plane are obtained from the total measured values thereof, and correspond to the plurality of guide marks. (Multi mark) A mid-point type punching machine has also been put into practical use.

Recently, as a method of quality assurance, a user of a multilayer printed circuit board has been required to provide quality information of a manufacturing process. As a circuit board manufacturer, it is necessary to measure the distribution of characteristic values of a product at the end of each process, and to preserve the result. The completion inspection of the circuit board should grasp the pattern deformation of the inner layer board more extensively than before and make data.

Therefore, until now, focusing on the conductor layer having the finest pattern and forming a guide mark therein has not been a problem in the manufacture of the multilayer circuit board, but in the future, the quantitative information of the conductor pattern deformation movement is also measured for other conductor layers, and the result It is becoming obligatory to keep it and provide it to users on demand. Since the amount of deformation movement of the conductor pattern represents a deviation between the conductor layers, it is generally referred to as "layer deviation".

Before completion inspection, for example, measuring interlayer disparity between patterns formed in each conductor layer during standard hole drilling after hot pressing process, it is possible to sort out the defects of the multilayer circuit board in the intermediate process. It is also useful as a manufacturer of circuit boards.

By the way, it is necessary to form guide marks in all the conductor layers in order to know the interlayer deviation of each conductor layer, and the total number of marks is double the number of conductor layers as compared with the case of forming guide marks only in the conventional one layer. Forming guide marks of the same size in each conductor layer results in an excessive space for installing the guide marks, and according to the pattern layout of the circuit board, a material having a larger external shape than the conventional one is required, resulting in an increase in raw material costs.

In addition, in order to reduce the error at the time of a measurement, the guide mark was measured as large as possible in the field of view of a camera, and so that the figure center (weight center) of the mark might be in the center of a field of view. Therefore, the measurable guide mark is one per measurement. For this reason, in order to observe these guide marks, the camera equipped with the reference hole perforator needs to move to each guide mark position, and the problem of the increase in machining time due to the increase of the observation time cannot be ignored.

In order to solve the problems as described above, the present invention is a hollow in which the inner side of the contour formed in one conductor layer constituting the inner layer of the multilayer printed circuit board (brighter than the surrounding image when viewed in an image) becomes a roux. A guide mark and a solid guide mark on the inside of the outline formed in the conductor layer adjacent in the substrate thickness direction (which is darker than the surrounding image when viewed in an image) to become a dark portion, and the conductor layer has a guide mark. When viewed in the direction of the substrate thickness, a solid guide mark is disposed inside the outline of the hollow guide mark, and a multilayer printed circuit board is provided in such a size that the outline of the hollow guide mark and the outline of the solid guide mark do not contact each other.

When the conductor layer of the inner layer of the multilayer printed circuit board is viewed in the direction of the thickness of the circuit board, the conductor pattern design of the inner layer of the multilayer printed circuit board coincides with the figure center position of the contour of the hollow guide mark and the contour center of the contour of the solid guide mark. Is placed in the city.

A plurality of guide mark frames having conductors removed are formed in the conductor layer of the multilayer printed circuit board, and the guide mark frames are placed at the same position of each conductor layer, and are viewed in the direction of the substrate thickness of the multilayer printed circuit board. A multi-layer formed in the guide mark frame with at least one set of guide marks formed of a size that fits within the field of view of the receiving part of the observing apparatus for observing the mark, and comprising a solid guide mark and a hollow guide mark disposed inside the hollow guide mark. It is also a printed circuit board.

It is also proposed to arrange a solid guide mark formed on the conductor layer of the inner layer of a specific multilayer printed circuit board in the center of the guide mark frame.

Moreover, it is also possible to define the contour which contains the contour of a hollow guide mark, and to use the annular guide mark which has a round ring shape with two contours in two concentric circles as a hollow guide mark.

A plurality of guide mark frames having conductors removed are formed in the conductor layer of the multilayer printed circuit board, and the guide mark frames are placed at the same position of each conductor layer and are viewed in the substrate thickness direction of the multilayer printed circuit board to observe the guide marks. A guide mark group formed of a size that fits within a field of view of an image receiving unit of an observation device, the guide mark group having at least one set of guide mark sets comprising a solid guide mark and a hollow guide mark disposed inside the hollow guide mark in the guide mark frame; An observation method for observing the interlayer deviation that observes and takes an image of the entire guide mark set in one guide mark group by one observation is proposed.

It is also proposed to calculate the coordinates of all the guide marks in the same guide mark frame on the basis of the position of the guide marks arranged in the center of the visual field.

Furthermore, a method for measuring interlayer deviation is also proposed in which the coordinate position of the inner layer is estimated by using all the coordinate values of the guide marks included in the guide mark group, or a part thereof, to determine the reference hole coordinates.

1 is a schematic diagram showing a guide mark according to an embodiment of the present invention.

2 is a view showing a shape of a guide mark according to an embodiment of the present invention formed on each inner layer substrate and an example of arrangement of a guide mark group formed in the inner layer substrate.

It is a schematic diagram which shows the guide mark observation method by X-ray, and a principle diagram explaining the abnormality of a guide mark image.

4 is a schematic diagram illustrating an image of a guide mark captured by a CCD image pickup device and a principle diagram illustrating an image processing method.

5 is an explanatory diagram of two types of guide marks according to another embodiment of the present invention.

6 is a perspective view of a reference hole perforator for observing a guide mark of the present invention to perform reference hole drilling.

7 is a front view and a side view of the reference hole perforator.

8 is a plan view showing the position of the moving table of the reference hole punch.

Fig. 9 is a projection view of each direction of the X moving mount of the reference hole puncher.

FIG. 10 is a perspective view showing the structure of a multilayer printed circuit board, a plan view, and a schematic diagram of a jig plate used in a hot press process.

11 is a cross-sectional view showing the structure of a multilayer printed circuit board.

12 is a front view and a plan view of a mid-point two-hole reference hole puncher.

* Description of the symbols for the main parts of the drawings *

1: perforator 2: enclosure

3: mount 4: the X-ray generator

4a: X-ray generator 5: X-ray protective tube

5a: Hole 6: X-ray camera

7: spindle 7a: chuck

7b: drill

7c, 9a: air cylinder 8: spindle mount

9: clamper 10: X mobile stand

11: Y mobile unit 12: mobile unit

10a, 11a, 12a: straight guide (LM guide)

10b, 11b, 12b: ball screw

16: Hole punched position (1, 2 holes) 17: Hole punched position (3, 4 holes)

17: worker position (white arrow) 20: guide mark group

21: guide mark frame 22: solid guide mark

23: hollow guide mark 24: torus guide mark

C1, C2, C3: Circles 22A, 23A: Contour

24N: Contour (inside) 24G: Contour (outside)

Subscript: 1, 2, 5 to 5 above the inner layer board

Surface (top) of innerlayer board a, Back surface (bottom) of innerlayer board b

30 X-ray fluorescent multiplication tube 31: fluorescent film

32: photoelectric surface 33: output fluorescent film

34: fluorescent lens system

35 CCD imaging device (charge coupled device) 35: phase

A: anode S: convergence electrode

50: machine coordinate system (Xm.Ym, Zm, machine origin Om)

51: design coordinate system (Ud, Vd, origin Od)

H1, H2: reference hole 60: multilayer printed circuit board

61: double-sided circuit board 61a: pattern of a single circuit board

62: conductor 63: (insulated) substrate

64: prepreg

64a: prepreg (with reference hole) 65: guide hole

66, 66a, 66b, P: Guide mark 67, H: Reference hole

68: lay up jig plate 68a: positioning pin

69: maximum circuit board outline 69a: minimum circuit board outline

70: range of influence Ha: guide mark for identifying inside and outside

As an embodiment of the present invention, the guide marks formed on the respective conductor layers of the multilayer printed circuit board inner layer substrate will be described with reference to FIGS. 1 and 2. Fig. 1 illustrates the case where there are 10 conductor layers forming the inner layer, Fig. 1 (a) is a schematic cross-sectional view of the guide mark portion of each conductor layer, and (b) a guide mark shown in the field of view of the X-ray camera for measurement. 2A shows guide marks 23-1b and 22-1b formed on the conductor layer of the inner layer 2 (the back surface of the double-sided circuit board 61-1 in FIG. 1), and FIG. b) shows the guide marks 23-2a and 22-2a formed in the conductor layer (the surface of the double-sided circuit board 61-2) of the inner layer 3rd layer, respectively.

The multilayer printed circuit board 60 of Fig. 1 is composed of ten inner layers (five double-sided circuit boards 61 for inner layers). Subscripts 1 to 5 are distinguished from the top of FIG. 1 (a), and for convenience, the subscripts a and b are used with the upper side of the drawing as the front side and the lower side as the back side.

Fig. 2C shows an arrangement example of the guide mark groups 20A to 20F in one multilayer printed circuit board 60. Figs.

In addition, other reference numerals are used in common with FIGS. 10 and 11 described above. Reference numeral 62 denotes an outer conductor and 63 an insulating substrate.

As shown in Fig. 1A, for example, the hollow guide mark 23-1b is formed in the substrate thickness direction with respect to the solid guide mark 22-1a formed on the surface of the double-sided circuit board 61-1. It is formed in the adjacent conductor layer in the vertical direction). The solid guide mark 22-1a and the hollow guide mark 23-1b are arranged concentrically in design.

In addition, the solid guide mark 22-1b is formed in the neighborhood of the hollow guide mark 23-1b by the same conductor layer, and is arranged concentrically with the hollow guide mark 23-2a formed in the adjacent conductor layer in the substrate thickness direction. do. Thus, the solid guide mark 22 and the hollow guide mark 23 are formed concentrically between the conductor layers adjacent in the substrate thickness direction, and the double-sided circuit board 61-5 is formed on the conductor layer on the surface of the double-sided circuit board 61-1. The mutual position is related to the conductor layer of the back surface.

In practice, the nine sets of solid guide marks 22 and hollow guide marks 23 are arranged in, for example, three rows and three columns so as to fall within the field of view of an approximately square X-ray camera as shown in Fig. 1 (b).

The multilayer printed circuit board 60 is formed with guide mark frames 21 (21-1a, 21-1b, 21-2a, ..., 21-5b) in which copper foil is removed from each inner conductor layer. It does not block X-rays. These ten guide mark frames 21 overlap to form voids from which unnecessary copper foils are removed, and the solid guide marks 22 and the hollow guide marks 23 disposed therein can be easily observed.

In addition, the presence or absence of copper foil in the outer side of this guide mark frame 21 is irrelevant.

On the X-ray camera image, guide marks formed on each layer are collectively observed as shown in Fig. 1 (b). Examples of the individual conductor layer patterns constituting this image are shown in Figs. 2A and 2B. (A) shows the back surface of the double-sided circuit board 61-1 from the surface, and guide frame 21 -b) shows a hollow guide mark 23-1b and a solid guide mark 22-1b, and (b) depicts the surface of the double-sided circuit board 61-2 to describe the guide mark frame 21. The hollow guide mark 23-2a and the solid guide mark 22-2a which are arrange | positioned inside -2a) are shown.

These shapes are overlapped to form an X-ray image shown in Fig. 1B.

In fact, the part used for calculation as a guide mark is the circular part (darkness in image) in which the copper foil of the center part remained in the solid guide mark 22, and in the case of the hollow guide mark 23, there is no copper foil of the center part (inside). It is a circular part (bright in image).

That is, the solid guide mark 22 is a shape in which the inside of the basic outline is represented by a dark part, and the hollow guide mark 23 is represented by a list in the inside. In principle, the shape of the contour is not particularly limited to any plan view type, but in this example, the contour is described as a concentric circle.

As an example of the practical size, referring to the reference numeral of FIG. 1 (b), one side F of the guide mark frame 21 is about 10 mm, the distance A between the guide marks is about 3 mm, and the solid guide mark 22 The outer diameter is 1.4 mm and the inner diameter of the hollow guide mark 23 is about 2.4 mm.

The size F of the guide mark frame 21 is set to be slightly smaller than the effective field of view of the X-ray camera, and the multilayer printed circuit board which has finished the hot pressing process is somewhat deformed, so that even if the position of each guide mark changes, it is sufficient within the field of view of the X-ray camera. This is the size to go in.

The shape example of the guide mark formed in the both conductor layers of an inner layer board | substrate is shown to FIG. 2 (a), (b). FIG. 2 (a) shows guide marks formed on the conductor layer on the back surface of the inner layer substrate 61-1 of the first sheet from above, and FIG. 2 (b) is adjacent to the conductor layer on the back surface of the inner layer substrate 61-1. The guide mark formed in the surface conductor layer of the inner layer substrate 61-2 is shown, and the center position of the solid guide mark 22-1b and the center position of the hollow guide mark 23-2a are compared. Here, the center means the center of the planar shape that forms the shape of the guide mark, that is, the center of the figure. By comparing the center positions of adjacent guide marks one by one, the position amount of the entire guide marks can be known.

As shown in Fig. 2 (c), the guide mark group for the circuit board 60 is formed in at least two places of 20A and 20B. By observing two guide mark groups, the center position distribution and rotation angle around the center of each conductor layer in the inner layer can be calculated, and the state of deformation near the straight line passing through the guide mark groups 20A and 20B can be reliably identified. have.

Guide mark groups 20C, 20D, 20E, and 20F are arranged at four corners of the circuit board 60, and the four guide mark groups are used to move the design coordinate origin of each conductor layer pattern in the inner layer and the direction of the coordinate axis. By calculating, it is possible to estimate the amount of planar deformation of the conductor layer of each of the multilayer printed circuit board 60.

The coordinate system having the origin Od and orthogonal coordinate axes Ud and Vd written in FIG. 2 (c) is a design coordinate system common to all conductor layers of all inner layers, and the position of the group of guide marks on the design is described in this design coordinate system. .

In addition, although guide marks are formed inside and outside all the double-sided circuit boards 60 in FIG. 1 (a), guide marks may be formed on some specific conductor layers without forming guide marks on all the conductor layers. For example, the interlayer deviation of the pattern inside and outside the double-sided circuit board 61 can be measured by a single inspection of the double-sided circuit board 61 before layup. none.

In addition, the guide mark of the layer can be omitted if the measurement of the deviation between the layers of the conductor layer, which is not important as a matter of understanding with the user, is unnecessary.

Here, the outline | summary of an X-ray generation tube and an X-ray camera is demonstrated with reference to FIG. (A) is a schematic diagram which shows the outline | summary of an X-ray camera, (b) is a schematic diagram explaining mark position and the shape on an X-ray camera output, (c) is a schematic diagram which shows the image position change by the thickness of a subject. to be.

Usually, the X-ray camera 6 incorporates an X-ray fluorescence pipe 30 as a light receiving unit. As shown in FIG. 3A, the X-ray fluorescence pipe 30 has an input target, a convergence electrode S, an anode A, and an output including a fluorescent film 31 having a photoelectric surface 32. The fluorescent film 33 and the like are incorporated.

The X-rays radiated from the X-ray generator tube 4a penetrate the inner layer where the guide marks 66 and the like of the multilayer circuit board 60 as the object are formed, enter the fluorescent film 31, and emit the fluorescent film 31. Is converted into the optical image 36. By this light, photoelectrons are emitted from the photoelectric surface 32 disposed closely to the inner surface of the fluorescent film 31. The output light flux is multiplied by a method such as increasing the acceleration voltage to form an image on the output fluorescent film 33. This image is captured by the CCD imaging device 35 which is a charge coupled device through the optical lens system 34.

In Fig. 3A, L1 is the distance between the X-ray source and the multilayer circuit board 60, and L2 is the distance to the fluorescent film of the X-ray multiplier. Unlike visible light, since X-rays cannot use an optical lens, the shadow is almost similar to the guide mark formed on the image 36 of the fluorescent film 31 and the multilayer circuit board, and the size is [(L2) / ( L1)].

Recently, in order to improve the sensitivity of the CCD image pickup device 35, the CCD image pickup device 35 is placed in close contact with the fluorescent film 31, and the image of the fluorescent film 31 is directly photographed by the CCD image pickup device. An X-ray camera, which is omitted, is also used, but the above relationship holds true.

Referring to Fig. 3B, the relationship between the image position on the fluorescent film and the subject and the image shape will be described. The image Z1 immediately below formed by the X-rays emitted from the X-ray generator tube with respect to the mark B1 having the center of view in the center of the camera's field of view resembles the original mark B1, and its center ( The center of the figure is also the center of view, which is the same position as the original mark B1. In this case, there is no change in the center position irrespective of L1 and L2.

The size of the image Z2 of the mark B2 in which the X-ray is incident at an angle α is changed in size by the previous equation, and the shape of the mark B2 and the image Z2 is not strictly similar to each other due to the small change of the angle α. If the contour shape of the mark B2 is a circle, the image Z2 becomes elliptical. However, the circle center is projected on the ellipse center, and the center position is on the line of the angle α. Even when the guide mark center is not the field of view, it can be corrected by simple proportional calculation by using the center position on the line of the angle α. Thus, the influence of the image distortion by X-ray incidence angle (alpha) can be avoided.

The fluorescent film 31 of the X-ray fluorescence pipe 30 may be spherical, and a slight error is added, but the increase in error is very small.

As exaggerated in Fig. 3 (c), if there are marks inside and outside the multilayer circuit board 60 serving as a subject, the difference appears at the image position by the distance between the marks (substrate thickness of the circuit board) t1 and t2. In practice, the marks B1 and B2 inside and outside are arranged concentrically, but when the X-rays have an incident angle α, the images Z1 and Z2 are not concentric. When the substrate thickness t1 is small, the error amount Q1 is small as shown in the upper half, and when the substrate thickness t2 is large, the error amount Q2 becomes very large as shown in the lower half, and when both guide marks overlap as shown in the exaggeration, the analysis becomes impossible.

As an example, when the maximum distance of the guide marks measured at 200 mm and L2 at 220 mm diagonally is 4.2 mm (22-1a position in Fig. 1 (b)), the angle α becomes about 1.2 ° and the substrate thickness If t1 is 0.2 mm or less, error amount Q1 is less than 5 micrometers, and it will not be a problem at all. When the substrate thickness t1 is about 0.5 mm, the error amount Q1 approaches 0.01 mm around the usage limit. Therefore, this influence can be minimized when comparing between guide marks formed in adjacent conductor layers such that the substrate thickness t1 is minimized.

In addition, the arrangement of the guide marks B1 in FIG. 3 (b) such that the center of the guide marks as the center of view is the field of view can be completely eliminated when the errors are shown in FIGS. 3 (b) and 3 (c).

The guide mark image imprinted on the CCD image pickup device is shown schematically in Fig. 4A1. Fig. 4 (a1) shows one set of guide marks in the guide mark group shown in Fig. 4 (a2) in an enlarged manner. If the brightness of the guide mark imprinted on the CCD imager 35 is binarized to an appropriate threshold value, the entire pixel is classified as either light or dark, and is divided into pixel shapes of the CCD imager 35 to form a mosaic. .

Here, the coordinate origin O is determined at the lower left corner of the image, and the orthogonal X and Y coordinate axes are drawn. For example, counting the number of bright pixels in the i-th pixel column from the origin O along the X-axis (since the number of pixels along the X-axis of the cut-out figure is already known) can also automatically obtain the dark pixel count. Similarly, the number of light and dark pixels of the j-th row of pixels at the origin O along the Y-axis is also known.

As described above with reference to FIG. 1, one set of guide mark images shown in FIG. 4 (a1) is superimposed on two types of guide mark images. This image is separated in software and the center coordinates of the figure are calculated from the number of pixels. Although there are many types of software analysis methods, an example thereof will be described with reference to FIG. 4 (b).

As shown in Fig. 4 (a1) or (b), the figure serving as a reference for calculating the center is the outline 22A which is the outer diameter of the solid guide mark 22 and the outline 23A which is the inner diameter of the hollow guide mark 23. to be.

A partition circle C1 having a diameter slightly larger than the contour line 22A of the solid guide mark 22 is defined, and the sum of the number of dark pixels existing inside the partition circle C1 and each coordinate axis inside the partition circle C1 are defined. Therefore, the moment (distance x weight) related to the origin O is added up. In this case, the distance is represented by the number of pixels from the origin O, and the weight is substituted by the number of dark pixels. For example, in Fig. 4 (a1), the moment of the i-th column along the X axis is [i x (number of dark pixels in the column) = 5 x 3]. When the sum of the moments in the partition circle C1 is divided by the number of dark pixels in the partition circle, the X coordinate of the center of the solid guide mark expressed in the number of pixels can be obtained. Also along the Y axis, for example, the j row moment becomes [8 × 5], and the Y coordinate of the center can be obtained by the same calculation.

Next, a partition circle C2 having a diameter slightly larger than the contour line 23A of the hollow guide mark 23 is defined. In addition, when the process which considers all the inside of the former division circle C1 as a bright pixel simultaneously, the solid guide mark 22 vanishes externally. The center coordinates of the hollow guide mark 23 can be known by calculating the center of the bright pixels in the partition circle C2.

By adding the partitions C1 and C2 in this manner, the centers of the solid guide mark 22 and the hollow guide mark 23 can be calculated independently. When this center calculation is performed for each set of solid and hollow guide marks, the center positions of all the guide marks in one guide mark frame are found and can be converted into the machine coordinate system set in the perforator by simple conversion.

In reality, the number of pixels assigned to one guide mark is much larger than that of Fig. 4A1, and the error in the center calculation is not a problem in practical use. Furthermore, in good multi-layered printed circuit boards, the displacement of the guide mark is small, and there is little fear that the pixels used for the center calculations will come out from the partition circles C1 and C2.

In this way, by combining two figures having the same center position as guide marks and arranging these two guide marks on two adjacent conductor layers, the coordinate difference between them can be calculated by comparing two guide marks for each set. For example, the error can be further reduced compared to the case where the center is calculated for each guide mark.

In addition, as described above, since the center of view of the X-ray camera has the smallest error, the coordinates in the machine coordinate system of this guide mark group are obtained using the guide mark in the center, and the coordinates of all guide marks in the guide mark group are represented by the machine coordinate system. The coordinates can be calculated simply. In order to correct the measured value, an integer numerical value around the X-ray camera determined from the beginning such as the magnification of the image by L1 and L2 shown in Fig. 3A may be input. The data input of the individual circuit boards is almost unnecessary. This ensures high measurement accuracy by observing the guide mark group.

It is also possible to calculate the coordinate values of the machine coordinate system on individual guide marks without using this procedure, but to individually correct the image magnification ratio, the influence of the substrate thickness, the position of the image center in the camera field of view, etc. Since it is necessary to input the numerical value of each board | substrate, it is complicated and the precision falls also considerably.

In the description of FIG. 1, the principle diagrams arranged in the first column of FIG. 1 (a) are folded in three rows and three columns of FIG. 1 (b), but need not be arranged from the upper left in order from the upper conductor layer, and concentric for each adjacent conductor layer. In accordance with the principle of making a solid, hollow guide mark set, the arrangement order may be arbitrarily changed, for example, a solid guide mark formed on the most important conductor layer is disposed at the center portion.

Moreover, as another form of a guide mark, the annular guide mark shown in FIG. 5 can also be used. All of FIG. 5 has shown typically the inside of the guide mark frame 20, and FIG. 5 (a1)-(a3) have shown that the hollow guide mark 23 of FIG. 1 was changed to the toric guide mark 24, 5 (b1) to (b3) show a case where a plurality of annular guide marks 24 are arranged concentrically. 5C is an explanatory diagram in the case where the partition member C3 is newly added and defined in software in addition to the partition members C1 and C2.

As shown in FIG.5 (c), the center can be obtained with the definition of the partition circle C1 about the inner solid guide mark 22 like FIG.4.

In the case of the annular guide mark 24 in which the outer contour of the hollow guide mark 23 is changed from a square to a circle, the annular guide mark 24 is defined by defining the partition circle C2 and treating it with the partition circle C1. May be regarded as a hollow guide mark having its inner diameter as the outline 24N. This case is equivalent to the hollow guide mark 23 in FIG. 1.

Further, a partition circle C3 that is slightly larger than the outer diameter of the toroidal guide mark 24 is defined, and at the same time, a process of considering the inside of the partition circle C2 as a dark pixel is performed to the dark pixels inside the partition circle C3. Calculation of the center is equivalent to a solid guide mark having the outer diameter of the toroidal guide mark 24 as the outline 24G.

In this manner, when the guide mark is a torus, it can be formed on the same basis as the hollow and solid guide marks only by software processing.

In particular, as shown in Fig. 5 (b1), when the outline constituting the guide mark is a concentric circle having a center in the center of the entire field of view, the influence of the error described in Fig. 3 (b) can be improved, so that the guide mark is observed at the time of observation. Can be observed with high accuracy just by paying attention to the center of view of the X-ray camera. If the field of view of the X-ray camera is about 10 mm, even if the line width and the interval equivalent to those of Fig. 1 (b) are employed, the six inner conductor layers can be covered. It can fully cope with the manufacture of general-purpose general purpose multilayer printed circuit boards.

As shown in Figs. 5 (b2) and 5 (b3), the guide marks formed of these concentric rings are also arranged such that adjacent annular rings are formed in the adjacent conductor layer, thereby reducing the influence of the thickness of the inner layer substrate shown in Fig. 3 (c). Can be.

Next, a reference hole perforator capable of observing a multilayer printed circuit board having guide marks formed at four corners as described above (multipoint midpoint method) will be described.

6 is an external perspective view of the perforator 1, and is shown through the enclosure 2. FIG. FIG. 7A is a front view of the perforator 1, and FIG. 7B is a side view. 8 (a) and 8 (b) are plan views in which the position of the movable table 12 of the perforator 1 is changed, and both FIGS. 7 and 8 show the inside of the enclosure 2 through the perspective view.

In addition, the machine coordinate system (origin Om, Xm, Ym, Zm) written in each figure is a coordinate system fixed to the floating part (for example, the enclosure 2 or the mount 3) of the perforator 1, and various machines of a conveying apparatus. The direction of movement of the part is parallel to this coordinate axis. The coordinate values obtained by observing the guide marks of the multilayer board with the X-ray camera or the puncturing coordinates of the reference holes are also basically calculated using this coordinate system.

In addition, the white arrow 17 of FIG. 6 is the operator's position, and the operator stands in the direction of the arrow (the direction of the Ym axis) and inserts a multilayer printed circuit board (not shown) to observe guide marks and perform standard hole drilling. When finished, take out from the punch (1).

In the following description, the multilayer printed circuit board, which is a work piece, observes a group of guide marks 20C, 20D, 20E, and 20F at four corners, as shown in FIG. For example, near 20A and 20B).

The mount 3 is fixed inside the enclosure 2 of the perforator 1. The left and right pairs of X movable mounts 10 are formed in a substantially channel shape, and have a mirror image relationship on the left and right. The X movable mount 10 is supported by a straight guide 10a disposed on the upper end of the mount 3, and is provided with a ball nut 10b and a ball nut attached to the lower surface of the X movable mount 10 engaging with the ball screw 10b. In accordance with the size of the circuit board for puncturing the reference hole, it moves in parallel with the Xm axis in advance and waits at the position where the guide mark can be observed.

And, in order to drive the X movable stand 10 individually, the ball screw 10b is disposed for each X movable stand 10.

The X-ray generator 4 is fixed to the upper portion of the X movable mount 10, and the linear guide 11a is attached to the lower portion. And the Y movable stand 11 is supported by the linear guide 11a. The Y movable stand 11 can be moved in parallel with the Ym axis by the ball screw 11b and the ball nut (not shown) attached to the lower surface of the Y movable stand 11 engaged therewith.

The Y movable stand 11 is formed in a channel shape and an X-ray protective tube 5 is disposed on the upper portion thereof, and as shown in FIG. 7, the air for moving the clamper 9 and the clamper 9 up and down in parallel with it. The cylinder 9a is provided. At the lower part, the spindle 7 and the X-ray camera 6 are fixed.

The movable table 12 on which the multilayer printed circuit board is mounted is supported and driven by a linear guide 12a and a ball screw 12b which are arranged in parallel with the Ym axis and fixed to the center of the housing, and move parallel to the Ym axis. .

The movable table 12 mounts the multilayered printed circuit board that drills the reference hole, which is a workpiece at the 12A position, moves along the Ym axis, and guides the guide mark to the reference hole drilling position.

In addition, a controller for driving the ball screws 10b, 11b, and 12b to control the movement of the X movable stand 10, the Y movable stand 11, and the movable stand 12 is not shown.

Here, as the main configuration of the perforator, the observation device of the guide mark is formed by the X-ray generator 4, the X-ray protective tube 5, and the X-ray camera 6, and drilled by the spindle 7 and the clamper 9 Forming device, X movable platform 10, Y mobile platform 11, mobile platform 12 and linear guides (10a, 11a, 12a) for supporting and driving them, ball screws (10b, 11b, 12b), etc. To form a driving device.

In addition, the control device, not shown, controls the various devices described above in accordance with a series of drilling operations. In addition, the control device calculates the coordinate value from the X-rays of the guide marks observed by the observation device, and calculates the reference hole drilling position from the coordinate value and the design coordinates of the reference hole previously input.

The observation method of the multilayer printed circuit board 60 shown in Fig. 2 (c) in which four guide mark groups 20C, 20D, 20E, and 20F are formed at four corners will be described.

First, the position along the Xm axis of the X movable mount 10 is determined from the external dimensions of the circuit board to be drilled and the coordinate values of the (design) guide mark groups 20C, 20D, 20E, and 20F, and the X movable mount ( 10) move there and wait.

In the 12A position (of FIG. 6) of the movable table 12, the operator places the multilayer printed circuit board 60 at a predetermined position on the movable table 12. The circuit board 60 is temporarily fixed to the movable table 12. The moving table 12 moves to the position where the guide marks 20C and 20D come under the X-ray generating tube 4a built in the X-ray camera 4.

As will be described later, the guide mark groups 20C and 20D are viewed with X-rays and observed with the X-ray camera 6, and the coordinate values of the guide marks 22 and 23 of each conductor layer are measured. The coordinate values are stored in the memory of the control device, not shown.

The table 12 that moves by the distance that the guide mark groups 20E and 2OF come under the X-ray generating tube 4a moves in the Ym direction. Subsequently, X-rays are irradiated to observe the guide mark groups 20E and 20F with the X-ray camera 6, and the coordinate values of the guide marks 22 and 23 of each conductor layer are stored.

Here, although the calculation method is mentioned later, the coordinates of the reference holes H1 and H2 are calculated from the coordinates of the four sets of guide mark groups, the moving table 12 moves to reach the positions of the reference holes H1 and H2, and the spindle (7) moves to the coordinates of the reference holes H1 and H2 to drill the reference holes H1 and H2. Reference holes H1 and H2 are not shown.

With reference to Fig. 9, how the mechanisms mounted on the X and Y movable mounts during the processing will be described.

9 (a) is a front view of the X mobile stand 10 and the Y mobile stand 11 on the left side from the worker position, (b) is a plan view to remove the upper half of the X mobile stand 10, the Y mobile stand ( The upper surface of 11) is shown. (c) and (d) show the X moving mount 10 viewed in the plus direction of the Xm axis, (c) shows the observation of the guide mark with the X-ray camera 6, and (d) the spindle. It shows typically when drilling with.

Observation of the guide mark groups 20C to 20F is performed at the X-ray observation position shown in Fig. 9C. An X-ray protective tube 5 and an X-ray camera 6 come directly under the X-ray generator tube 4a.

The X-axis generator is operated by a command of a control device, not shown, and the X-rays radiated from the X-ray generator tube 4a pass through the hole 5a drilled in the center of the X-ray protective tube. (12) One of the inner layer guide mark groups of the circuit board 60 placed thereon, for example, 20C, is captured by the X-ray camera 6 as an image, and the captured image is transferred to a calculator in the control device, The coordinates of the guide marks 22, 23, 24, etc. are calculated and stored. Usually, two guides are observed twice to observe four guide mark groups, and the coordinates of the reference hole are calculated from the observation data.

Drilling of the reference hole is performed by the drill 7b at the tip of the spindle. At the time of drilling, the movable stand 12 is moved according to the calculated coordinate value of the reference hole, the X movable stand 10 moves to the Xm coordinate axis of the reference hole H1, and the Y movable stand 11 moves to the reference hole H1. Fine adjustment is performed to move to the Ym coordinate axis. Since the Y movable stand 11 is always set based on the center of the X-ray camera 6, the Y-axis movable stand 11 is actually the center of the X-ray camera 6 as shown in FIG. And as much as the distance S between the center of the spindle 7. The spindle 7 is a high speed motor using an air turbine or a high frequency motor as a rotation source. The spindle 7 is mounted with a drill 7b made of cemented carbide through a chuck 7a attached to a rotating shaft, and a reference hole is mounted on a circuit board. Perforate. Although not shown, the feed for drilling the drill 7b is performed by an air cylinder or a servo motor which moves the spindle 7 up and down.

The clamper 9 disposed directly below the spindle 7 is attached to an actuator of the air cylinder 9a, and when lowered, presses the circuit board 60 placed on the movable table 12 to drill the circuit board 60 at the time of drilling. ) To prevent movement.

The above is the mechanical sequence of the perforator for observing the guide mark group and drilling the reference hole based on the observation result.

Next, a method of calculating the position of the inner conductor layer of the multilayer printed circuit board 60 from the observation result of the guide mark group will be described.

When designing the conductor pattern of the inner layer conductor layer of the multilayered printed circuit board 60, it has already been described to set a design coordinate system whose coordinate axes are orthogonal Ud and Vd common to all the inner layer conductor layers. When put into the drilling machine, for example, the Ud axis is determined in parallel with the Xm axis of the machine coordinate system, and the Vd axis is determined in parallel with the Ym axis. At the same time as the conductor pattern, the guide marks are written at predetermined coordinate positions as components of the guide mark group.

In addition, the shape of a guide mark group is shown to FIG. 1 (b), For example, let solid guide mark 22 be a representative guide mark of the layer. From the observation results of the four guide marks 22, the coordinate values described in the machine coordinate system of the four solid guide marks can be known. From the measured values of the four guide marks 22 formed in one conductor layer, it is estimated where the design coordinate systems of Ud and Vd are located and regarded as the arrangement of this conductor layer. In other words, it is only necessary to obtain the coordinate values representing the origin of the design coordinate system in the machine coordinate system and the slope of the Xd axis of the Ud axis.

There are several methods for estimating and calculating the apparent value from statistical measurements, but the center of the design guide is calculated by assuming the observation point (solid guide mark 22) as the unit quality, and the center is floated. From the values and the coordinates of the measured guide marks, a method of obtaining the slope of the Ud axis with respect to the Xm axis is minimized.

A specific example of the calculation procedure is filed in Japanese Patent Application No. Hei 11-293271 by the same applicant, and therefore will be described very schematically here.

Here, in preparation, the center Gd, which regards each guide mark as a unit quality, is calculated from the design coordinates of the solid guide mark described above, and the coordinate axis U is parallel to Ud, and the coordinate axis V is set to Vd, with the center as the origin. The coordinate value of each guide mark is converted into the parallel coordinate system.

The center coordinates are calculated from the measured coordinate values of the actual guide marks, and the measured values are converted into a coordinate system whose coordinate axis is parallel to the machine coordinate system. The slope of the coordinate axis can be obtained from the design coordinate value and the measured value.

In this way, the conductor layer positions of all inner layers are obtained by the origin coordinate values (GXm, GYm) described in the machine coordinate system and the inclination of the coordinate axis (angle α between the Xm axis and the U axis). This is also the interlayer deviation data.

The coordinates of the reference hole described in the design coordinate system are converted into coordinate values of the machine coordinate system from the origin coordinates and the inclinations GXm, GYm, α of the coordinate axis, and the spindle 7 moves and drills at the position.

The position of the reference hole may be calculated using the data of the conductor layers of all the inner layers of one multilayer printed circuit board, or the position of the reference hole may be determined from the data of particularly important conductor layers. Since the displacement of each of the conductor layers of the inner layers, which are usually between the 4th and 10th layers, can be obtained, there are various methods for determining the position of the reference hole therefrom, and these may be determined individually from the characteristics of the actually manufactured circuit board.

The numerical value of the gap between layers of each conductor layer is stored in the memory of the punching machine and can be submitted according to the user's request, which is also useful for quality control of the manufacturer.

Standard hole drilling after hot pressing process is a necessary step in the subsequent process such as pattern etching of the conductor layer on the surface, drilling of through-holes, etc., and cutting the outline on a single circuit board, and the gap between the inner conductor layers during this standard hole drilling process. Can be measured without increasing machining time.

As described above as a reference hole puncher, when only the punching function is removed from the puncher, the measuring device observes guide marks and stores data. Although a large-capacity storage device and a measuring device characterized by high-speed measurement are also independent product fields, measuring means such as X-ray cameras are almost common with the perforator, and the description of the perforator also includes the functional description of the measuring device.

As described above, a plurality of guide marks formed on the inner conductor layer of the multilayer printed circuit board are arranged in the same camera field of view, and all the guide marks in one field of view are simultaneously taken by one X-ray irradiation. The deviation between the layers of the inner conductor layer can be measured. It is very effective to provide production control information according to user's demand without increasing processing time. The manufacturing side can also obtain appropriate intermediate management information in advance, so the economic effect of improving production yield can be expected.

In addition, since guide marks formed between adjacent conductor layers are arranged concentrically, measurement can be minimized by the reduction in measurement accuracy due to the thickness of the inner layer substrate and the insulating substrate.

If the guide mark form which arranged the several annular guide mark concentrically is employ | adopted, it is effective for the measurement of the interlayer shift | deviation of the inner layer conductor layer with a relatively small number of layers.

In addition, as a reference mark perforator for multi-marks, it is possible to evaluate the applicable viscosity at a degree of adding some software in calculating the center position after taking an image.

Claims (11)

A hollow guide mark in which the inside of the contour formed in one conductor layer constituting the inner layer of the multilayer printed circuit board becomes a roll; It is provided with the solid guide mark in which the inside of the contour formed in the conductor layer adjacent to the said one conductor layer in the board | substrate thickness direction becomes a dark part, The solid guide mark is disposed inside the outline of the hollow guide mark when viewed in the substrate thickness direction of the multilayer printed circuit board, and the size of the hollow guide mark and the outline of the solid guide mark do not come into contact with each other. Multilayer printed circuit board. The method of claim 1, When designing the inner conductor pattern of the multilayer printed circuit board so that the figure center position of the contour of the hollow guide mark and the figure center position of the contour of the solid guide mark coincide with each other when viewed in the substrate thickness direction of the multilayer printed circuit board. Arranged multilayer printed circuit board. The method according to claim 1 or 2, Forming a plurality of guide mark frames from which conductors are removed in an inner conductor layer of the multilayer printed circuit board, The guide mark frame is positioned at the same position of each conductor layer, and is formed to have a size that fits within the field of view of the water phase of the observation device for observing the guide mark by seeing in the substrate thickness direction of the multilayer printed circuit board. And a set of at least one guide mark set comprising the solid guide mark and the hollow guide mark disposed inside the hollow guide mark in the guide mark frame. The method of claim 3, And a solid guide mark formed on the inner conductor layer of the specific multilayer printed circuit board in the center of the guide mark frame. The method of claim 2, A multi-layer printed circuit board which defines an outline containing the outline of the hollow guide mark, and uses an annular guide mark having two outlines as two concentric circles as a hollow guide mark. The conductors are removed from the inner conductor layer of the multilayer printed circuit board at the same position of the respective conductor layers, and the conductors are removed to a size within the field of view of the receiving portion of the observing apparatus for observing the guide marks by viewing them in the substrate thickness direction of the multilayer printed circuit board. A plurality of guide mark frame is formed, A guide in which a solid guide mark formed in the conductor layer of one of the inner layers is disposed inside the hollow guide mark formed in the adjacent conductor layer, and at least one set of guide mark sets comprising the solid guide mark and the hollow guide mark are disposed As a method for measuring interlayer deviation of a multilayer printed circuit board having a mark group provided therein, Acquiring images of all the guide mark sets in the one guide mark group by one observation to measure interlayer deviation; Determination of the gap between the layers of the multilayer printed circuit board comprising a. The method of claim 6, And calculating the coordinates of all the guide marks in the same guide mark frame on the basis of the position of the guide marks disposed at the center of the field of view. The method of claim 6, Estimating the coordinate position of the inner layer and determining the reference hole coordinates using all or some of the coordinate values of the guide marks included in the guide mark group. The method of claim 2, And a solid guide mark formed on the inner conductor layer of the specific multilayer printed circuit board in the center of the guide mark frame. The method of claim 3, A multi-layer printed circuit board which defines an outline containing the outline of the hollow guide mark, and uses an annular guide mark having two outlines as two concentric circles as a hollow guide mark. The method of claim 4, wherein A multi-layer printed circuit board which defines an outline containing the outline of the hollow guide mark, and uses an annular guide mark having two outlines as two concentric circles as a hollow guide mark.