JP3493931B2 - Method of forming printed circuit board having inspection electrode - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a printed circuit board having test electrodes used for testing the continuity of a semiconductor device or a printed circuit board. 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 an object to be inspected as is known from a wafer probe or a wiring test. Had gone. In addition, a wiring circuit board for inspection having electrodes is formed on a wiring circuit board having a relatively low wiring density,
The continuity test is performed by taking contact with the printed circuit board, which is the test object, via the anisotropic conductive sheet. In a conventional method for inspecting the continuity of a semiconductor device or a printed circuit board by means of a wafer probe or a wiring inspection, a needle-like inspection electrode is brought into contact with the inspection mark, so that an inspection mark is formed on the object to be inspected. And may cause serious damage such as penetration of an electrode to the device under test. Also, it has been difficult to form a probe for inspection due to an increase in wiring density and high integration. 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. In addition, the use of an anisotropic conductive sheet has a high contact resistance and causes an increase in wiring resistance, which causes a decrease in reliability of a continuity test. The present invention has been made to solve the above problems, without leaving the test marks in the test subject, and to provide a method of forming a wiring circuit board having testing electrodes to accommodate the inspection of fine pitch. [0004] In order to solve the above-mentioned problems in the present invention, a method of forming a printed circuit board having an inspection electrode, comprising the following series of steps, is provided. (A) forming a resist layer 2 on a base substrate 1; (B) forming a through hole 3 in the base substrate 1 and the resist layer 2; (C) At the same time as forming the resist layer 4 on the entire surface including the through hole 3 on the resist layer 2a in which the through hole 3 is formed, the protrusion 5
Forming a . (D) forming a thin-film conductor layer over the entire surface of the resist layer 2a in which the through holes 3 are formed and the base substrate 1a; (E) A plating resist layer 6 is formed on the thin film conductor layer, and is subjected to a patterning process to form a plating resist pattern 6a.
Forming a. (F) A step of forming the wiring conductor layer 7 on the thin film conductor layer by electrolytic plating using the plating resist pattern 6a as a mask. (G) A step of forming a wiring circuit by removing the plating resist pattern 6a and the thin film conductor layer below the plating resist pattern 6a. (H) Base base on which a wiring circuit including wiring conductor layer 7 is formed
Forming an insulating resin layer 8 on the entire surface of the board 1a on the wiring conductor layer 7 side; (I) A step of removing the resist layer 4 and the resist layer 2a in which the through-holes are formed, and forming an inspection electrode 9 having a hemispherical recess at the tip . The printed circuit board having the inspection electrode manufactured by the above-described forming method can cope with a fine pitch that could not be handled until now, and furthermore, a hemispherical recess is formed at the electrode tip. Thus, the contact at the time of inspection is ensured, the resin layer is provided inside the electrode, and the unevenness of the object to be inspected is absorbed by the entire substrate, so that damage to the object to be inspected can be prevented. In addition, the contact resistance can be reduced, and the inspection can be performed without increasing the wiring resistance. A method of forming a printed circuit board having electrodes according to the present invention comprises forming a resist layer 2 on a base substrate 1, and forming through holes 3 in the base substrate 1 and the resist layer 2. To form Next, a resist layer 4 is further formed on the resist layer 2a in which the through holes 3 are formed, and at the same time, a convex portion 5 is formed. Next, a thin-film conductor layer is formed on the base substrate 1a and the resist layer 2a in which the through holes 3 are formed, and a wiring conductor layer 7 and a wiring circuit are formed by a semi-additive method. Further, an insulating resin layer 8 is formed on the printed circuit board including the wiring conductor layer 7, and the inside of the inspection electrode is filled with resin. By removing the resist layer 4 and the resist layer 2a in which the through holes are formed, the inspection electrode 9 having a hemispherical recess at the tip end is formed.
Are formed to produce a printed circuit board having inspection electrodes (see FIGS. 1A to 1I). Hereinafter, we describe details of the method for forming a wiring circuit board having testing electrodes. It is desirable that the base substrate 1 has high chemical resistance and heat resistance and does not undergo thermal expansion or contraction due to a change in temperature. Specifically, polyimide films 20 to 50
Use μm. A resist layer 2 formed on a base substrate 1
Can be used a dry film resist generally known as an etching resist. The use of a dry film having a uniform thickness facilitates control of the inspection electrode height. Select the thickness of the dry film according to the inspection electrode height. Laser processing is used to form the through holes 3. Excimer laser processing or short-pulse carbon dioxide laser processing can be used for laser processing. These laser processing methods are desirably selected depending on the size of the inspection electrode to be formed. Inspection electrode diameter is 100-200μm
In the case of (1), carbon dioxide laser processing is suitable, and in the case of 100 μm or less, excimer laser processing is suitable. In the case of laser processing, various shapes of through-holes can be formed by inserting a mask into the optical system, so that various types of electrodes can be manufactured. After forming the through holes 3, a resist layer 4 is formed on the resist layer 2a in which the through holes 3 are formed. The resist layer 4 forms a convex portion 5 at a portion where the through hole 3 is in contact with the resist layer 4, and controls the shape of the tip portion of the inspection electrode by the convex portion 5. In the case where the resist layer 4 is formed by, for example, a film bonding method, the protrusions 5 control the amount and shape of the protrusion by adjusting the heating and pressing conditions during bonding. This resist layer 4 can be formed by laminating a dry film resist. After forming the resist layer 4, a wiring conductor layer 7 is formed by a semi-additive method. In the semi-additive method, after a thin film conductor layer is formed on the entire surface of a substrate, a plating resist 6 is formed, a patterning process is performed to form a plating resist pattern 6a, a wiring conductor layer 7 is formed by electrolytic plating, and a plating resist pattern 6a is formed. And a method of forming a wiring circuit by removing the thin film conductor layer below the plating resist pattern 6a. The thin film conductor layer below the plating resist pattern 6a is removed by soft etching. An insulating resin layer 8 is formed on the entire surface of the substrate on which the wiring circuit including the wiring conductor layer 7 is formed on the wiring conductor layer 7 side ,
The resin is filled inside the inspection electrode. The edge resin layer 8 can be formed by screen printing or spin coating of a thermosetting epoxy resin or a polyimide resin. As the resin characteristics, those having flexibility so that the unevenness of the substrate can be absorbed when the electrodes are in contact with each other are preferable. This can be improved by dispersing the rubber filler in the resin. Further, a dry film type permanent resist may be used. After forming the insulating resin layer 8, the resist layer 4
By removing the resist layer 2a in which the through-holes are formed, it is possible to form the printed circuit board having the test electrodes on which the test electrodes 9 having the hemispherical recesses are formed. An embodiment will now be described with reference to FIGS. 1 (a) to 1 (i).
This will be described in detail with reference to FIG. Example 1 A 30 μm thick polyimide film is used for the base substrate 1. A dry film (DFR: manufactured by Hitachi Chemical Co., Ltd.) is laminated on a base substrate 1 by a laminator to form a resist layer 2. Lamination conditions: lamination temperature: 100 ° C, lamination speed: 1 m
/ Min (see FIG. 1A). Next, through holes 3 having a diameter of 50 μm were formed in the base substrate 1 and the resist layer 2 using an excimer laser processing machine (see FIG. 1B). Excimer laser processing conditions were an energy density of 1.0 J / cm ² . A dry film (DFR: manufactured by Hitachi Chemical Co., Ltd.) is further laminated on the resist layer 2a in which the through holes 3 are formed by a laminator to form a resist layer 4 and a projection 5 (FIG. 1 (c)). reference). The bonding conditions at this time are as follows: roll temperature: 100 ° C., roll pressure: 3 kg / cm
^{Was 2} . Copper was sputtered by sputtering over the entire surface of the base substrate 1a and the resist layer 2a in which the through holes 3 were formed, thereby forming a thin-film conductor layer (not shown). The thickness of the thin film conductor layer was 3000 °. Further, a photosensitive resist (PMER: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied using a spin coater to form a plating resist 6 (FIG. 1).
(D)). Next, the plating resist 6 is patterned to form a plating resist pattern 6a (FIG. 1).
(E)). Next, a copper wiring conductor layer 7 having a thickness of 10 μm is formed on the thin film conductor layer by electrolytic copper plating using the plating resist pattern 6a as a mask (see FIG. 1 (f)), and the plating resist pattern 6a is removed. Then, the thin film conductor layer below the plating resist pattern 6a was removed by soft etching to form a wiring circuit (see FIG. 1 (g)). Next, a thermosetting epoxy resin is coated on the printed circuit board including the wiring conductor layer 7 by screen printing to form an insulating resin layer 8 having a thickness of 30 μm, and the inside of the inspection electrode is filled with resin ( FIG. 1 (h)). Further, after the insulating resin is completely cured, an alkaline solution (5
% Sodium hydroxide solution) to remove the resist layer 4 and the resist layer 2a in which the through-holes are formed, thereby obtaining a printed circuit board on which the test electrode 9 having a hemispherical recess at the tip is formed (FIG. 1 (i)). <Embodiment 2> After forming a resist layer 2 on a base substrate 1 in the same process as in Embodiment 1, 100 μm was formed using a carbon dioxide gas laser.
A through hole 3 of φ was formed. Further, the resist layer 4, the plating resist pattern 6
a, of forming a wiring conductor layer 7 and the insulating resin layer 8, the resist layer 2a resist layer 4 and the through holes are formed by removing, inspection electrodes 9 the tip portion has a hemispherical recess formed
A printed circuit board having the inspection electrodes obtained was obtained. By using the printed circuit board having the inspection electrodes manufactured by the forming method of the present invention, it is possible to cope with fine pitches which could not be dealt with up to now, and to provide the electrode tip portion. By forming a hemispherical recess in the test piece, contact with the test object can be reliably obtained even if the electrode is inclined during the test. Further , conduction can be achieved without damaging the substrate to be inspected at the time of contact with the substrate to be inspected. Also book
According to the forming method of the present invention, variation in the electrode height can be reduced , so that the contact accuracy with the substrate to be inspected can be increased. Since the printed circuit board itself absorbs the unevenness of the object to be inspected, an anisotropic conductive sheet is not required unlike the related art. As a result, the inspection can be performed without low contact resistance and no increase in wiring resistance. 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. 1 (a) to 1 (i) are partial cross-sectional views showing forming steps of one embodiment of a method for forming a printed circuit board having test electrodes according to the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 1/06-1/073 G01R 31/02 H01L 21/3205 H01L 21/66 H05K 3/00

Claims (1)

(57) [Claim 1] A method for forming a printed circuit board having an inspection electrode, comprising the following series of steps. (A) forming a resist layer (2) on a base substrate (1); (B) forming a through hole (3) in the base substrate (1) and the resist layer (2); (C) Forming a resist layer (4) on the entire surface including the through hole (3) on the resist layer (2a) in which the through hole (3) has been formed, and simultaneously forming the convex portion (5). the step of. (D) forming a thin-film conductor layer on the entire surface of the resist layer (2a) in which the through-holes (3) are formed and the base substrate (1a); (E) forming a plating resist layer (6) on the thin-film conductor layer and patterning to form a plating resist pattern (6a); (F) forming a wiring conductor layer (7) on the thin film conductor layer by electrolytic plating using the plating resist pattern (6a) as a mask; (G) a step of forming a wiring circuit by removing the plating resist pattern (6a) and the thin film conductor layer below the plating resist pattern (6a). (H) base forming a wiring circuit including the wiring conductor layer (7)
Forming an insulating resin layer (8) on the entire surface of the substrate (1a) on the side of the wiring conductor layer (7) . (I) a step of removing the resist layer (4) and the resist layer (2a) in which the through-holes are formed, and forming a test electrode (9) having a hemispherical recess at the tip .