JPS5854520B2 - Printed board manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to printed boards, and more particularly to multilayer printed boards improved to reduce crosstalk between signal patterns.

In recent years, with the miniaturization of transistors, ICs, and other electronic components, the wiring density of printed circuit boards has become higher and signal patterns are arranged closer to each other.

Therefore, between signal patterns arranged in parallel in close proximity, the so-called crosstalk phenomenon occurs, such as when the electrical signal of one signal pattern mixes with the adjacent signal pattern, preventing the signal from harming the signal or generating noise. Ru.

In order to prevent such losstalk, the present applicant has already proposed a printed board in which a ground pattern is provided between each signal pattern on the wiring pattern forming plane to isolate each signal pattern from each other.

However, even in such a printed board, crosstalk cannot be completely eliminated, and when a printed board is multilayered, crosstalk between signal patterns on each layer cannot be completely eliminated.

The present invention has been made in view of the above points, and includes a printed board having a ground pattern and a signal pattern, in which part or all of the vicinity of the cross section of the signal pattern is surrounded by the ground pattern via an insulating layer. An object of the present invention is to provide a method for manufacturing a printed circuit board in which the occurrence of crosstalk is reduced.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a first embodiment of a printed board according to the present invention in a general manufacturing process.

First, a grounding copper film 2 is formed on both sides of an insulating substrate 10 (Figure A).

A commercially available double-sided copper clad board may be used for this purpose. Since printed boards are formed on both sides of the substrate 1 in the same manufacturing process, only the upper side of the substrate 1 will be described below.

A photosensitive non-medium resin, that is, a resist 3 capable of electroless plating is coated on the upper side of the copper film 2, leaving grooves 4 for forming an earth pattern (Figure B).

In this case, according to the usual resist coating work process, resist is first applied to the entire surface, and then the groove hole 4 is formed by covering with a pattern film, exposing it to light, baking it, and developing it.

Next, a copper ground pattern 2/ is grown in the groove hole 4 by electrolytic plating to the thickness of the resist 3 (FIG. 0).

Next, a photosensitive non-catalytic resin, that is, an electroless adhesive resist 5 is applied thereon, and a ground pattern forming groove 6 is provided on both ground patterns 21.
, 6 is provided with a signal pattern forming groove 6' (
Figure D).

Next, copper is grown to the thickness of the electroless metal resist 5 by electroless plating in the grooves 6 and 67.

At this time, since the bottom of the signal pattern forming slot 6' is the resist 3 which can be plated electrolessly, plating is possible.

In this way, a ground pattern 2/ that is electrically connected to the signal pattern 2/l and the copper film 2 is formed as shown in Figure E.

The ground pattern 2' is similar to the process shown in the next KB diagram.
Electroless plating resist 3 is applied leaving groove holes 7 at the positions (FIG. F).

Subsequently, a ground pattern 2' is formed in the groove hole 7 by electrolytic plating (Figure G).

Subsequently, a copper film 2'' is formed on the entire surface by electroless plating (Figure H).

In this case, in order to shorten the plating work time, a thin copper film may be formed on the resin by electroless plating, and then copper may be plated and grown by electrolytic plating.

This also applies to the case where electroless plating is performed on the resin in each of the following examples.

As described above, the periphery of the cross section of the signal pattern 2// is connected to the grounding pattern 2' through the insulating material (in this case, the electroless plating resist 3 and the electroless plating resist 5) and the grounding copper conductive to it. Membrane 2,2///V
It can be surrounded more completely than C.

By using a multilayer printed board manufactured by repeating the above steps, crosstalk between signal patterns can be prevented and the reliability of a device using the printed board can be increased.

FIG. 2 is a cross-sectional view of another embodiment of the printed board according to the present invention, showing the valley manufacturing process.

First, a signal pattern 15 is formed on the substrate 1 according to a conventional method, and an uncured resin 16 is applied thereon (FIG. A).

Next, the UTC (
The thin copper film 8 of Ultra Thin Copper) 17 is pressed from above toward the substrate 1 through an elastic material 18 such as rubber (Figure B).

At this time, it is desirable to use a vacuum lamination method to remove air components from the crimped portion.

Therefore, the UTC 17 is curved along the shape of the signal pattern 15 and is bonded to the substrate 1 via the resin 16 (FIG. 0).

Subsequently, the aluminum film 9 of the UTC 17 is removed, and a resist 19 is applied to the necessary portions above the signal pattern 15 (FIG. D).

Next, unnecessary parts of the copper thin film 8 are removed by etching (E
figure).

As described above, a part of the periphery of the cross section of the signal pattern 15 can be surrounded by the ground pattern made of the copper thin film 8.

FIG. 3 is a sectional view of a printed circuit board at each step in another embodiment of the present invention.

A signal pattern 21/and a ground pattern 2' are formed on one side of the board 1, and a ground pattern 2''' is formed on the opposite side (lower side) of the board 10 with a width that covers the gap between the two upper ground patterns. (Figure A).

Each of these pattern forming steps is performed by print etching or the like on a double-sided copper clad board.

Next, another substrate 11 on which an earth pattern 2'' having the same shape as the earth pattern 2'' on the lower side of the substrate 1 is formed is pressure bonded to the substrate 1 coated with an uncured resin 16 (Figure B).

The ground pattern 2'' on this other substrate 1' is formed by print etching or the like on a single-sided copper clad plate.

In this way, as shown in FIG. 0, the periphery of the cross section of the signal pattern 2'' can be surrounded by the valley ground patterns 2', 2'''.

Note that if a resin with a low dielectric constant (for example, polybutadiene, fluorinated resin, polyethylene A, etc.) is appropriately selected and used as the uncured resin 16, the transmission speed can be increased.

This also applies to each of the embodiments disclosed in this specification.

FIG. 4 is a sectional view showing each manufacturing process of a printed board according to another embodiment of the present invention.

First, a signal pattern 21 is formed on the UTC 17, and this is laminated via the prepreg 12 on the substrate 1 in which the groove 20 is formed (Figure A).

Next, leaving the signal pattern 21 buried in the groove 20,
Remove TC17 (Figure B).

Next, the upper surface of this signal pattern 21 is covered with an insulating resin 22 (for example, resist), and a plating layer 23 having a thickness of about 1 to 2 .mu.m is applied to the surface (FIG. 0).

Next, a resist 24 is applied to areas other than the ground pattern forming area (Figure D).

Subsequently, a ground pattern 25 is formed by electrolytic plating,
After removing the resist, the copper film under the resist is removed by etching (Figure E).

In this way, a part of the periphery of the cross section of the signal pattern 21 can be surrounded by the ground pattern 25 via the insulating resin 22.

FIG. 5 is a sectional view showing each manufacturing process of a printed board according to another embodiment of the present invention.

A resist 31 is applied to the copper thin film 8 side of the UTC 17 consisting of the copper thin film 8 and the aluminum film 9, and a ground pattern 29 is formed on the non-coated portion by plating growth (Figure A).

The UTC 17 coated with the resist 31 is laminated on the substrate 1 on which the signal pattern 30 is formed via the prepreg 12 .

After the UTC 17 and the substrate 1 are bonded together by pressure bonding, the aluminum film 9 of the UTC is removed (FIG. 0).

As described above, a part of the periphery of the cross section of the signal pattern 30 can be surrounded by the ground layer made of the copper thin film 8 and the ground pattern 29.

In this case, resist remains in the insulating layer around the signal pattern 30, so the dielectric constant decreases.

FIG. 6 is a sectional view showing each manufacturing process of a printed board according to another embodiment of the present invention.

In this case, the difference from the embodiment shown in FIG. 5 is that the resist is peeled off after forming the ground pattern 29 on the UTC 17, and the substrate 1 on which the UTC 17 and the signal pattern 30 are formed is bonded to a powder resin 32 with a low dielectric constant. It is to join using.

FIG. 7 is a sectional view showing the process of manufacturing the valleys of a printed board according to another embodiment of the present invention.

First, a groove 20 is formed on a substrate which has insulating properties and is soluble or non-dissolvable by light or other treatment by iK laser processing or the like (see Fig. A).

Next, electroless plating and electrolytic plating are applied to the surface of this substrate 10 to form a copper film 2 (Figure B). Next, resin 33 is embedded in the groove 20 in which this copper film 2 is formed, and the entire surface is electroless plated. A copper film 34 is formed (Figure C).

A resist 35 is applied on this copper film 34 in accordance with a pattern (Figure D).

Subsequently, a signal pattern 36/ is formed on the upper part of the resin 33 in the groove 20 by electrolytic plating, and a copper pattern layer which is to become the ground pattern 36 is formed in the middle part of the valley groove 20, and the resist is removed (FIG. E).

Next, copper by the thickness of the copper film 34 formed by electroless plating is removed from the entire surface by etching (FIG. F).

Next, a resist 37 is applied to the entire surface (Figure G).

Next, the resist 37 on the ground pattern 36 is removed by exposing, printing and developing using a pattern film (not shown), leaving the signal pattern 36' buried in the resist 37 (Figure H).

Subsequently, copper is grown on the ground pattern 36 by electrolytic plating, and after reaching the resist 3 f0 surface position, a copper film 39 is formed on the entire surface by electroless plating to make the valley ground patterns 36 conductive (Figure 1). .

Next, unnecessary parts of the copper film 39 are removed by etching (5
figure).

In this manner, the cross section of the signal pattern 36' can be completely surrounded by the copper films 2, 39 and the ground pattern 36.

FIG. 8 is a sectional view showing the process of manufacturing the valleys of a printed board according to another embodiment of the present invention.

Two signal patterns 40 are formed on both sides of the first substrate 1.

A ground pattern 41 wider than the signal pattern 40 is formed on each of the second and third substrates 1/1''.

These eleventh second and third substrates are arranged so that the corresponding signal patterns 40 and ground patterns 41 face each other with the prepreg 12 in between, and are laminated by applying force as shown by the arrow from above and below (Figure A). .

Therefore, the second substrate 1' and the third substrate 1/' are stacked on the first substrate 1 while being curved according to the shape of the signal pattern 40 (FIG. B).

In this way, a portion of the cross-sectional periphery of the signal pattern 40 can be left and surrounded by the ground pattern 41.

FIG. 9 is a sectional view showing each manufacturing process of a printed board according to another embodiment of the present invention.

First, apply V cyst 43 to the top surface of the copper plate 42 (Figure A)
.

Next, cover this upper surface with a pattern film 44 (Figure B),
Remove unnecessary resist areas by exposure, baking, and development (
Figure C).

Next, four grooves 45 are formed in the copper plate 42 by etching (Figure D).

Next, a resin 46 is filled into this groove 45 (Fig. E).

Subsequently, a groove 45' communicating with the groove 45 on the upper surface is formed on the lower surface of the copper plate 42 according to the same process, and a resin 46 is filled in the same manner (FIG. F).

Next, V cyst 43 is applied to both sides of this copper plate 420, covered with a pattern film 44 (Figure G), and after exposure, baking, and development, the remaining resist remains while the surface of the copper plate between the two central resin parts 46 is covered with resist 43. (Figure H).

Subsequently, a copper film 47 is formed over the entire upper and lower surfaces by electroless plating and electrolytic plating (FIG. 1).

Next, a resist 43 is applied onto this copper film 47 and covered with a pattern film 44 (Figure 5), and unnecessary portions of the resist are removed by exposure, baking, and development (Figure K).

Subsequently, a ground pattern 47' is formed by etching (Figure L).

In this way, if the copper plate between the two resin parts 46 in the center is used as a signal pattern 42'' and the copper plate part on the opposite side is used as a ground pattern 42', the signal pattern is completely surrounded by the ground pattern via the insulating layer. It turns out.

In this case, the process after the state shown in Figure H, that is, the state in which four resin parts are formed on the copper plate 42 and the resist 43 is applied to cover the copper plate between the two central resin parts, is as shown in Figure 10. A method may also be used.

That is, a copper film 41'' is formed on both surfaces by electroless plating (Figure I').

Next, a resist 43 is applied to the entire surface and a pattern film 44 is applied.
Cover with / (J' figure) and remove the resist on the ground pattern forming part (K/ figure).

Next, a ground pattern 47' is formed by electrolytic plating (Figure L).

Subsequently, the copper film 47'' formed by the electroless plating performed in the process shown in FIG. 17 above is removed by etching (FIG. L).

In this way, the sea urchin signal pattern can be completely surrounded by the ground pattern as in FIG. 9 (L).

FIG. 11 is a sectional view showing each manufacturing process of a printed board according to another embodiment of the present invention.

A resist 54 is applied according to a pattern on the copper plate 53, and grooves 55 are formed by etching (FIG. A).

An uncured resin 5 with a low dielectric constant is placed in the resist removal groove 55.
6. Fill with polybutadiene, for example (Figure B).

The copper plate 53 thus formed is integrated with the substrate 5T on which the signal pattern 58 is formed by thermocompression bonding (Figure C).

Next, apply a resist 59 to the necessary areas (Figure D), and remove unnecessary copper by etching (Figure E) In this way, about half of the cross-sectional periphery of the signal pattern 58 is coated with the resin 56.
It can be surrounded by a copper plate 53 as a ground pattern via the ground pattern.

FIG. 12 is a sectional view showing each manufacturing process of a printed board according to another embodiment of the present invention.

A signal pattern 48 and an earth land 49 are formed on the substrate 1 (Figure A).

This may be formed using a double-sided copper-clad laminate.

Covering each signal pattern 48 with resist 50 (Figure B)
.

Next, for thickening, a copper film 52 is formed on the entire surface by electroless plating, and a resist 51 is applied to necessary parts (FIG. 0).

The unnecessary copper film is removed by etching and the resist is peeled off (Figure D).

In this way, approximately half of the cross-sectional periphery of the signal pattern 48 can be surrounded by the copper film 52, which is the ground pattern, via the resist 50, which is the insulating layer.

FIG. 13 is a sectional view showing the process of manufacturing the valleys of a printed board according to another embodiment of the present invention.

A signal pattern 61 and a ground land 60 are formed on a substrate 1 made of a copper-clad laminate.

Next, the signal pattern 61 is made of an insulating resin 62 with a low dielectric constant.
5 (Figure B).

Next, a conductive resin 63 is coated on the part to be the ground pattern by screen printing (Figure 0).

As described above, the cross section of the signal pattern 61 can be partially surrounded by the ground pattern.

FIG. 14 is a sectional view showing each manufacturing process of a printed board according to another embodiment of the present invention.

A signal pattern 64 and a ground land 65 are formed on the copper-clad laminate board 1 (Figure A).

On the signal pattern 64 is a resist 66 that can be plated electrolessly.
An electroless metal resist 67 is applied on the earth land 65 (Figure B).

A ground pattern 68 having a thickness of 10 to 20 μm is formed by electroless copper plating (Figure 0).

The electroless metal resist on the ground land 65 is removed (Figure D).

Thereafter, through holes and the like are formed in the earth land 65.

As described above, a part of the periphery of the cross section of the signal pattern 64 can be surrounded by the ground pattern 68 via the insulating resist 66.

FIG. 15 is a sectional view of a printed board showing a valley process in a method for manufacturing a printed board according to another embodiment of the present invention.

First, the substrate 1 is etched by laser processing, resin etching, or other mechanical methods along the positions corresponding to the signal pattern.
A groove 20 is formed in (Figure A).

Next, a copper film 2 as a ground layer is formed on the surface of the substrate 10 including the inner surface of the groove 20 by electroless plating (Figure B).
.

Next, the signal pattern 8 formed on the UTCII copper thin film 8
The UTCII and the substrate 1 are arranged so that / faces the groove 20 of the substrate 1, and the two are pressed together via the prepreg (adhesive sheet) 12 (Figure 0).

Next, the aluminum film 9 of the UTCl 1 is peeled off, and the copper thin film 8 is removed by etching, leaving only the signal pattern 8' in the groove of the substrate 1. Subsequently, a grounding copper film 14 is formed on the surface via the resin 13. (Figure D).

As described above, the periphery of the cross section of the signal pattern 8/ can be surrounded by the ground pattern, leaving only a portion.

FIG. 16 is a sectional view showing the process of manufacturing the valleys of a printed board according to another embodiment of the present invention.

A copper film 2 is formed on the surface of an insulating substrate 10 (Figure A).

A resist 26 is applied leaving the area around the area corresponding to the signal pattern (Figure B).

The copper film in the non-resist coated area is removed by etching, and the resist 26 is further removed (C).

Next, grooves 2γ are formed in the substrate 1 by resin etching (
Figure D).

Next, a copper film 28 is formed by electroless plating and electrolytic plating (Fig. E).

Subsequently, a resist 26 is applied around the groove 27.

Next, unnecessary portions of the copper film 28 are removed by etching to form a ground pattern 28'.

Next, the signal pattern 21 formed on the UTCl7 is placed in the groove 2γ.
The UTCl 7 and the substrate 1 are stacked with the prepreg 12 interposed therebetween (Figure H).

After thermocompression bonding of UTC17 and substrate 1, signal pattern 2
UTC is removed leaving only 1 inside the ground pattern 28' (Figure ■).

As described above, a part of the periphery of the signal pattern 21 (7) Fr surface can be surrounded by the ground pattern 28'.

As explained above, in the printed board according to the present invention, the ground pattern is formed so as to surround all or part of the cross section of the signal pattern, so crosstalk development between each signal pattern is greatly reduced, and signal transmission is improved. Reliability is greatly increased.

In addition, by repeating each manufacturing method of the printed board according to the present invention explained based on each drawing, or by stacking the manufactured printed board in multiple stages to make it multilayered and used as a multilayer printed board, the crosstalk phenomenon can be eliminated. The effect is even more pronounced.

[Brief explanation of the drawing]

FIGS. 1 to 16 are printed board cross-sectional views sequentially illustrating each step of each method for manufacturing a printed board according to the present invention. 1, 1', 1'', 57...Substrate, 2
', 25, 28' 29, 36, 41, 42', 47',
68...Earth pattern, 2", 8', i5, 2
1, 30, 36'. 40.42", 48, 58, 61, 64... Signal pattern, 2.2"', 28, 34, 39, 47°4
7”', 52...Copper film, 3.66...
Resist capable of electroless plating, 4, 6... Groove for forming ground pattern, 5, 67... Resist capable of electroless plating, 6/... Groove for forming signal pattern Hole, 7... Slot, 10.19, 24, 26,
31,35,37゜43.50,5L 54,59・
...Register, 11.17...UTC,
12...Prepreg, 13.16,22,33
, 46, 56, 62... Resin, 63...
・Conductive resin.

Claims (1)

[Claims] 1 (a) Step of forming a first layer made of earth metal on a substrate: (b) Applying a resist on the first layer, and forming at least two earth patterns on this resist. (c) forming a second layer by plating and growing an earth pattern metal conductive to the first layer in the groove of the resist up to the surface position of the resist; (d) forming a second layer;
a step of applying a resist on the layer, providing ground pattern forming grooves continuous to both ground patterns of the second layer in the resist, and further providing a signal pattern forming groove in an intermediate portion between these two grooves; (e) forming a third layer by plating and growing each pattern metal in each groove of the resist up to the surface position of the resist; (f) applying a resist on the third layer;
Step of providing a continuous ground pattern forming groove only at a position corresponding to the ground pattern of the layer; Q: Plating and growing the ground pattern metal in the groove of the resist coated on the third layer up to the resist surface position. A method for producing a printed board, comprising: (h) forming a fifth layer made of a ground metal for making each of the ground patterns of the fourth layer conductive with each other. 2(a) A step of growing an earth pattern plating conductive to the metal surface layer using a resist on a thin plate having a metal surface layer; (b) A step of forming a signal pattern on a substrate different from the thin plate; ( C) removing the resist from the thin plate on which the earth pattern has been formed; (d) laminating the thin plate from which the resist has been removed on the substrate via an insulating material; 3(a) Forming at least two grooves on one side of the copper plate; (b) Filling the grooves with insulating resin; (c)
Step of forming a groove on the opposite side of the copper plate so that the corresponding grooves communicate with each other; (d) Filling the groove formed on the opposite side with an insulating resin; (e) Step of filling the groove formed on the opposite side with an insulating resin; A step of covering the exposed copper between both grooves on both surfaces of the copper plate with a resist, and surrounding the copper plate between the grooves with an insulating material; (f) After applying the resist, both sides of the copper plate are electrically connected to the copper plate outside the grooves. forming a ground metal layer;
A method for manufacturing a printed board consisting of: