JP3562166B2 - Method of forming printed circuit board having inspection electrode - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing an inspection jig substrate used for conducting a continuity inspection of a semiconductor device or a printed circuit board.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a continuity test of a semiconductor device or a printed circuit board, a continuity test is performed by bringing a needle-shaped test electrode into contact with an electrode portion of a test object, as is known from a wafer probe or a wiring test. In the case of a wiring circuit board having a relatively low wiring density, a wiring circuit board for inspection having electrodes is formed, and a contact with a wiring circuit board to be inspected is taken through an anisotropic conductive sheet to conduct a continuity test. Is going.
[0003]
[Problems to be solved by the invention]
In a conventional method for inspecting the continuity of a semiconductor device or a printed circuit board by a wafer probe or a wiring inspection, a needle-like inspection electrode is brought into contact with the inspection electrode, so that there is a possibility that an inspection mark is left on the object to be inspected and damaged. Also, due to an increase in wiring density and higher integration, it has become difficult to form a probe for inspection. The method using an inspection substrate can cope with an object to be inspected having a pitch of about 200 μm due to the conductive pitch of the anisotropic conductive sheet and the like, but cannot cope with an inspection with a finer pitch than that. The present invention has been made to solve the above problems, provides a method of forming a wiring circuit board having testing electrodes having improved inspection electrodes and forming method corresponding to the inspection of fine pitch.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem in the present invention, in the test electrode connected to the wiring circuit, the surface area decreases as the shape of the test electrode approaches the electrode tip, and the tip is flat. A printed circuit board having an inspection electrode is provided. By adopting the above structure, it is possible to respond to fine pitches that could not be handled until now, and by flattening the tip of the electrode, it is possible to prevent damage to the test object at the time of inspection. Can be.
[0005]
According to the first aspect of the present invention, there is provided a method for forming a printed circuit board having an inspection electrode, comprising the following series of steps.
(A) forming an insulating resin layer on a base substrate;
(B) forming an opening in the insulating resin layer;
(C) forming a conductor electrode in the opening;
(D) forming a conductor thin film layer on the conductor electrode and the insulating resin layer;
(E) forming a second insulating resin layer on the conductive thin film layer;
(F) forming a second opening in a wiring pattern in the second insulating resin layer;
(G) forming a conductor layer in the second opening of the second insulating resin layer to form a wiring circuit;
(H) forming a third insulating resin layer on the wiring circuit and the second insulating resin layer;
(I) forming a test electrode and a printed circuit board by removing the base substrate, the insulating resin layer, and the conductive thin film layer other than the conductive electrode portion;
Through these steps, a printed circuit board having an inspection electrode with a fine pitch and a smooth electrode tip can be formed.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
In the structure of the printed circuit board having the inspection electrodes according to the present invention, an insulating resin layer 12 is formed on a base substrate 11 and an opening 13 is formed. Next, a conductor electrode 14 is formed in the opening 13. Further, a conductive thin film layer 15 and a second insulating resin layer 16 are formed on the entire surface of the substrate. A second opening 17 having a wiring pattern is formed in the second insulating resin layer 16. Further, a conductor layer is formed in the second opening 17, and a wiring circuit 18 is formed. A third insulating resin layer 19 is formed on the wiring circuit 18 and the second insulating resin layer 16a. Thereafter, the printed circuit board having the inspection electrodes of the present invention is obtained by removing the base substrate 11, the insulating resin layer 12a, and the conductive thin film layer 15 other than the conductive electrodes 14 (see FIG. 1).
Hereinafter, a printed circuit board having an inspection electrode and a method for forming the same will be described.
[0007]
Since the base substrate 11 is used as a plating electrode for forming the conductor electrode 14, a metal plate having conductivity and smoothness is preferable, and specifically, a copper plate having a thickness of 0.2 to 1.0 mm. And iron / nickel alloy plates can be used.
[0008]
Next, an insulating resin layer 12 is formed on the base substrate 11 (see FIG. 1A). The insulating resin layer 12 is not particularly limited as long as it is an insulating resin layer, and is selected according to a method of forming the opening 13 in a later step. When the openings 13 are formed by photolithography, it is necessary to select a material having photosensitivity and good resolution depending on the electrode pitch. In this case, a dry film resist may be selected. The use of a dry film having a uniform thickness facilitates control of the electrode height.
[0009]
Next, an opening 13 is formed in the insulating resin layer 12 (see FIG. 1B). As a method for forming the opening 13, a photolithography method, a laser processing method, or the like can be used. The method can be appropriately selected depending on the opening diameter of the opening, shape controllability, processing accuracy, and the like. Processing methods are preferred.
In the case of laser processing, since the insulating resin layer 12 does not particularly require photosensitivity, a wide range of materials can be selected. Excimer laser processing or short-pulse carbon dioxide laser processing can be used for laser processing. It is not particularly limited to these, and any material can be used as long as it can remove an organic substance. Further, it is desirable to select a processing method depending on the processing accuracy of the opening (in this case, the opening diameter). When the opening diameter is 100 to 200 μm, carbon dioxide laser processing is good, but when the opening diameter is 100 μm or less, excimer laser processing is suitable. In the case of laser processing, various shapes of openings can be formed by inserting a mask into the optical system, and thus the electrode shape can be selected.
[0010]
Next, a conductor electrode 14 is formed in the opening 13 (see FIG. 1C). Examples of the method for forming the conductor electrode 14 include an electrolytic plating method, an electroless plating method, a printing method using a conductive paste or an injection method, and the reproducibility of the shape of the conductor electrode 14 and the reliability of electrical conduction with the printed circuit board. Can be appropriately selected and used. Here, the conductor electrode 14 is formed by an electrolytic plating method excellent in shape reproducibility and conduction reliability.
Further, there is an electrode structure in which a gold plating layer 24 is formed at the tip of a conductor electrode in order to improve the contact reliability of the inspection electrode (see FIG. 2B).
[0011]
Next, the conductor thin film layer 15 is formed on the substrate surface (see FIG. 1D). As a method for forming the conductive thin film layer 15, a sputtering method, an evaporation method, an electroless plating method, an electrolytic plating method, or the like can be used.
[0012]
Next, a second insulating resin layer 16 for forming a wiring circuit is formed on the conductive thin film layer 15 (see FIG. 1E). The second insulating resin layer 16 is roughly classified into two types, a photosensitive insulating resin layer and a non-photosensitive insulating resin layer, and is appropriately selected depending on a processing method in a later step. As a method for forming the insulating resin layer, a resin solution or a photosensitive resin solution containing a thermosetting epoxy resin or a polyimide resin as a main component is screen-printed, spin-coated, roll-coated, or laminated by dry film. It is formed.
[0013]
Next, a second opening 17 having a wiring pattern is formed in the second insulating resin layer 16 (see FIG. 1F). As a method for forming the second opening 17, a photolithography method, a laser processing method, or the like can be applied.
[0014]
Next, a conductor layer is formed in the second opening 17 by electrolytic plating using the base substrate as an electrode, and a wiring circuit 18 is formed (see FIG. 1G).
[0015]
Next, a third insulating resin layer 19 is formed (see FIG. 1H). The third insulating resin layer may be the same as the insulating resin layer and the second insulating resin layer. However, the third insulating resin layer absorbs irregularities of the object when the electrodes come into contact with the object. It is desirable that the insulating resin layer 19 has flexibility. Specifically, improvement can be seen by adding a rubber filler to the above resin.
[0016]
Next, the base substrate 11 is removed by etching. Further, the insulating resin layer 12a is removed, and the conductor thin film layer 15 other than the portion 15a in contact with the conductor electrode 14 is removed by etching, thereby forming the inspection electrode 20 and the printed circuit board 40 (FIG. 1 ( i)).
Through these steps, a printed circuit board having the inspection electrode of the present invention can be formed.
[0017]
【Example】
Hereinafter, embodiments will be described in detail with reference to the drawings.
<Example 1>
As the base substrate 11, a copper plate having a thickness of 0.2 mm is used. A dry film (DFR: manufactured by Hitachi Chemical Co., Ltd.) was formed on a base substrate 11 by lamination, and was cured by heating to form an insulating resin layer 12 (see FIG. 1A).
[0018]
Next, an opening 13 having a diameter of 50 μm was formed in the insulating resin layer 12 using an excimer laser processing machine (see FIG. 1B). The conditions for the excimer laser processing were an energy density of 1.0 J / cm ² .
[0019]
Next, the opening 13 is subjected to electrolytic copper plating (electrolytic copper plating bath: copper sulfate 20 g / l, sulfuric acid 70 g / l, hydrochloric acid 50 ppm, current density 2 A / dm ² ) using the base substrate 11 as a plating electrode. 14 was formed (see FIG. 1C).
[0020]
Next, copper was sputtered on the surface of the substrate, followed by electrolytic copper plating to form a conductive thin film layer 15 (see FIG. 1D). The copper sputtered layer was formed to a thickness of about 3000 °, and was further subjected to electrolytic copper plating to form a conductor thin film layer 15 having a thickness of 1 to 3 μm.
[0021]
Next, a thermosetting epoxy resin solution was screen-printed on the conductive thin film layer 15 to form a coating film, and then heat-cured to form a second insulating resin layer 16 (see FIG. 1E).
[0022]
Next, the second insulating resin layer 16 was processed into a wiring pattern by excimer laser processing to form a second opening 17 (see FIG. 1F).
[0023]
Next, electrolytic copper plating (electrolytic copper plating bath: copper sulfate 20 g / l, sulfuric acid 70 g / l, hydrochloric acid 50 ppm, current density 2 A / dm ² ) is performed on the second opening 17 using the base substrate 11 as a plating electrode. Then, a wiring circuit 18 was formed (see FIG. 1F).
After the wiring circuit 18 is formed, the surface of the wiring circuit 18 is blackened (oxidized), whereby the adhesion to the third insulating resin layer 19 to be formed next can be improved.
[0024]
Next, a thermosetting epoxy resin solution was screen-printed to form a coating film, and then heat-cured to form a third insulating resin layer 19 having a thickness of 50 μm (see FIG. 1 (g)).
[0025]
Next, after the base substrate 11 was removed by etching, the insulating resin layer 12a was peeled and removed with a predetermined peeling liquid. Further, the conductor thin film layer 15 other than the portion 15a in contact with the conductor electrode 14 was removed by etching to produce the test electrode 20 and the printed circuit board 40 (see FIG. 1 (i)).
Through these steps, a wiring board having the inspection electrodes of the present invention was obtained.
[0026]
<Example 2>
In the same process as in Example 1, a 0.2 mm thick Cu plate was used as the base substrate 21, and a plating resist (PMER: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was coated on the base substrate 21 by spin coating. The layer 22 was formed (see FIG. 2A). Next, an opening 23 having a diameter of 30 μm was formed using an excimer laser processing machine. The processing conditions were the same as in Example 1.
Next, a gold plating layer 24 of 1 μm was formed by electrolytic gold plating on the bottom of the opening 23 using the base substrate 21 as an electrode (see FIG. 2B).
[0027]
Further, the conductive electrode 25, the conductive thin film layer 26, and the second insulating resin layer 27 are formed in the same process as in the first embodiment, and the second insulating resin layer 27 is processed into a wiring pattern to form the second opening 28. Then, a wiring circuit 29 was formed in the second opening by electrolytic copper plating, and a third insulating resin layer 30 was formed (see FIGS. 2C to 2H).
[0028]
Lastly, in the same process as in Example 1, the base substrate 21 was removed by etching, and then the insulating resin layer 22a was peeled off by a predetermined peeling liquid. Further, the conductive thin film layer 26 other than the portion 26a in contact with the conductive electrode 25 was removed by etching to produce the test electrode 31 and the printed circuit board 50 having the gold plating layer 24 formed at the tip of the conductive electrode 25. (See FIG. 2 (i)).
Through these steps, a printed circuit board having the test electrodes of Example 2 could be obtained.
[0029]
【The invention's effect】
By using the printed circuit board having the inspection electrode of the present invention, electrical continuity can be obtained without damaging the substrate to be inspected at the time of contact with the substrate to be inspected. In addition, in the method of forming an inspection electrode according to the present invention, there is no variation in the height of the inspection electrode, so that the contact accuracy can be increased. Since the substrate itself absorbs the unevenness of the object to be inspected, an anisotropic conductive sheet is not required unlike the related art. This makes it possible to cope with a test object having a fine pitch. In addition, since the shape of the electrode can be set relatively freely, the degree of freedom in designing the substrate can be improved as compared with the related art.
[Brief description of the drawings]
FIGS. 1A to 1I are partial cross-sectional views illustrating a manufacturing process of a printed circuit board having an inspection electrode according to a first embodiment of the present invention.
FIGS. 2A to 2I are partial cross-sectional views illustrating manufacturing steps of a printed circuit board having an inspection electrode according to a second embodiment of the present invention.
[Explanation of symbols]
11, 21 ... base substrates 12, 22 ... insulating resin layers 12a, 22a ... insulating resin layers 13, 23 with openings formed ... openings 14, 25 ... conductor electrodes 15, 26 ... conductor thin film Layers 15a, 26a: Conductive thin film layers 16, 27 etched; Second insulating resin layers 16a, 27a: Second insulating resin layers 17, 28 with second openings formed: Second openings 18, 29 wiring circuits 19, 30 third insulating resin layers 20, 31 inspection electrodes 24 gold plating layers 40, 50 wiring circuit board

Claims (1)

A method for forming a printed circuit board having an inspection electrode comprising the following series of steps.
(A) forming an insulating resin layer on a base substrate;
(B) forming an opening in the insulating resin layer;
(C) forming a conductor electrode in the opening;
(D) forming a conductor thin film layer on the conductor electrode and the insulating resin layer;
(E) forming a second insulating resin layer on the conductive thin film layer;
(F) forming a second opening in a wiring pattern in the second insulating resin layer;
(G) forming a conductor layer in the second opening of the second insulating resin layer to form a wiring circuit;
(H) forming a third insulating resin layer on the wiring circuit and the second insulating resin layer;
(I) forming a test electrode and a printed circuit board by removing the base substrate, the insulating resin layer, and the conductive thin film layer other than the test electrode portion;

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