Method for Forming Resist Pattern, Method for Producing Circuit Board, and Circuit Board

• US 20090236137A1
• Filed: 05/17/2006
• Published: 09/24/2009
• Est. Priority Date: 05/17/2006
• Status: Active Grant

• Current Assignee: Shinko Electric Industries Company Limited (Fujitsu Limited), Mitsubishi Paper Mills Limited
• Original Assignee: Shinko Electric Industries Company Limited (Fujitsu Limited), Mitsubishi Paper Mills Limited
• Inventors: Kaneda, Yasuo, Toyoda, Yuji, Fukase, Katsuya, Komuro, Toyokazu, Irisawa, Munetoshi, Sakai, Toyoaki
• Granted Patent: US 8,143,533 B2
• Time in Patent Office: Days
• US Class Current: 174/262
• CPC Class Codes: H05K 1/116 Lands, clearance holes or other lay-out details concerning the surrounding of a via
• CPC Class Codes: H05K 2201/09545 Plated through-holes or blind vias without lands
• CPC Class Codes: H05K 2203/0191 Using tape or non-metallic foil in a process, e.g. during filling of a hole with conductive paste
• CPC Class Codes: H05K 2203/0574 Stacked resist layers used for different processes
• CPC Class Codes: H05K 2203/1184 Underetching, e.g. etching of substrate under conductors or etching of conductor under dielectrics; Means for allowing or controlling underetching
• CPC Class Codes: H05K 2203/1394 Covering open PTHs, e.g. by dry film resist or by metal disc
• CPC Class Codes: H05K 3/002 by liquid chemical etching
• CPC Class Codes: H05K 3/108 by semi-additive methods; masks therefor characterised by metallic etch mask H05K3/062; electroplating methods or apparatus H05K3/241
• CPC Class Codes: H05K 3/426 initial plating of through-holes in substrates without metal

Abstract

There are provided a method for forming a resist pattern for preparing a circuit board having a landless or small-land-width through-hole(s) to realize a high-density circuit board, a method for producing a circuit board, and a circuit board. A method for forming a resist pattern, comprising the steps of forming a resin layer and a mask layer on a first surface of a substrate having a through-hole(s), and removing the resin layer on the through-hole(s) and on a periphery of the through-hole(s) on the first surface by supplying a resin layer removing solution from a second surface opposite to the first surface of the substrate, and a method for producing a circuit board using the method for forming a resist pattern, and a circuit board.

Claims

1. A method for forming a resist pattern, comprising the steps of forming a resin layer and a mask layer on a first surface of a substrate having a through-hole(s) and removing the resin layer on the through-hole(s) and on a periphery of the through-hole(s) on the first surface by supplying a resin layer removing solution from a second surface opposite to the first surface of the substrate.

2. The method for forming a resist pattern according to claim 1, wherein the resin layer and the mask layer are integrally formed.

3. The method for forming a resist pattern according to claim 1, wherein the resin layer is a photocrosslinkable resin layer.

4. The method for forming a resist pattern according to claim 1, wherein the substrate having a through-hole(s) is an insulating substrate having a conductive layer on the surface of the substrate and on the inner wall of a through-hole(s).

5. A method for producing a circuit board, comprising the steps of

(a) preparing an insulating substrate having a through-hole(s), which has a first conductive layer on a first surface, on a second surface opposite to the first surface and on an inner wall of the through-hole(s),

(b) covering the first conductive layer and an opening of the through-hole(s) on the first surface with a photocrosslinkable resin layer and a mask layer by forming the photocrosslinkable resin layer and the mask layer on the first surface,

(c) uncovering the first conductive layer on the periphery of the through-hole(s) on the first surface by supplying a photocrosslinkable resin layer removing solution from the second surface and removing the photocrosslinkable resin layer on the through-hole(s) and on a periphery of the through-hole(s) on the first surface,

(d) subjecting the photocrosslinkable resin layer on the first surface to pattern exposure,

(e) covering the first conductive layer and an opening of the through-hole(s) on the second surface with a photocrosslinkable resin layer and a mask layer by forming the photocrosslinkable resin layer and the mask layer on the second surface,

(f) removing the mask layer on the first surface,

(g) uncovering the first conductive layer on the first surface and the first conductive layer on a periphery of the through-hole(s) on the second surface by supplying a photocrosslinkable resin layer removing solution from the first surface and removing an uncured photocrosslinkable resin layer on the first surface and the photocrosslinkable resin layer on the through-hole(s) and on the periphery of the through-hole(s) on the second surface,

(h) subjecting the photocrosslinkable resin layer on the second surface to pattern exposure,

(i) removing the mask layer on the second surface,

(j) uncovering the first conductive layer on the second surface by supplying a photocrosslinkable resin layer removing solution from the second surface and removing an uncured photocrosslinkable resin layer on the second surface,

(k) forming a second conductive layer on the first conductive layer uncovered on the inner wall of the through-hole(s) and the periphery of the through-hole(s) and on the first surface and the second surface by electrolytic plating,

(l) uncovering the first conductive layer on the first surface and the second surface by removing the cured photocrosslinkable resin layers on the first surface and the second surface, and

(m) removing the uncovered first conductive layer by flash etching in this order.

6. The method for producing a circuit board according to claim 5, wherein the step (f) is performed before the step (e).

7. The method for producing a circuit board according to claim 5, wherein the step (f) is performed before the step (d).

8. The method for producing a circuit board according to claim 5, wherein the step (g) comprises the steps of (g1) uncovering the first conductive layer on the first surface by supplying the photocrosslinkable resin removing solution from the first surface and removing the uncured photocrosslinkable resin layer on the first surface and (g2) uncovering the first conductive layer on the periphery of the through-hole(s) on the second surface by supplying the photocrosslinkable resin removing solution from the first surface and removing the photocrosslinkable resin layer on the through-hole(s) and on the periphery of the through-hole(s) on the second surface, and the step (e) is performed between the step (g1) and the step (g2).

9. A circuit board comprising a land conductive layer formed on a periphery of a through-hole(s) of an insulating substrate having the through-hole(s), a circuit conductive layer constituting a circuit wiring on a surface of the insulating substrate, and a conductive layer on an inner wall of the through-hole(s), wherein an outer side surface of the land conductive layer in a part not connected to the circuit conductive layer has an inclination angle smaller than 90 degrees.

10. The circuit board according to claim 9, wherein the outer side surface of the land conductive layer in the part not connected to the circuit conductive layer has an inclination angle of 60 to 80 degrees.

11. The circuit board according to claim 9, wherein a difference between the diameter formed by the outer side surface of the land conductive layer and a diameter of the through-hole(s) when the hole(s) is formed is 0 to 80 μ

m.

12. The circuit board according to claim 9, wherein the inclination angle of the outer side surface of the land conductive layer in the part not connected to the circuit conductive layer is smaller than the inclination angle of a side surface of the circuit conductive layer.

13. The circuit board according to claim 9, wherein a side surface of the circuit conductive layer has the inclination angle of about 90 degrees.

14. The circuit board according to claim 9, wherein the land conductive layer is formed concentrically with the through-hole(s).

15. A method for producing a circuit board, comprising the steps of

(A) preparing an insulating substrate having a through-hole(s), which has a conductive layer on a first surface, on a second surface opposite to the first surface and on an inner wall of the through-hole(s),

(B) covering the conductive layer and an opening of the through-hole(s) on the first surface with a first resin layer and a mask layer by forming the first resin layer and the mask layer on the first surface,

(C) uncovering the conductive layer on a periphery of the through-hole(s) on the first surface by supplying a first resin layer removing solution from the second surface and removing the first resin layer on the through-hole(s) and on the periphery of the through-hole(s) on the first surface,

(D) providing a treatment for provision of resistance against a second resin layer removing solution to the resin layer on the first surface,

(E) removing the mask layer on the first surface,

(F) covering the conductive layer and an opening of the through-hole(s) on the second surface with a second resin layer and a mask layer by forming the second resin layer and the mask layer on the second surface,

(G) uncovering the conductive layer on a periphery of the through-hole(s) on the second surface by supplying a second resin layer removing solution from the first surface and removing the second resin layer on the through-hole(s) and on the periphery of the through-hole(s) on the second surface, and

(H) removing the mask layer on the second surface in this order.

16. A method for producing a circuit board, comprising the steps of

(I) forming an etching resist layer on the uncovered conductive layer,

(J) removing the first resin layer and the second resin layer,

(K) forming a photocrosslinkable resin layers on the first surface and the second surface,

(L) photocrosslinking curing the photocrosslinkable resin layers on the first surface and the second surface in a pattern by pattern exposure,

(M) uncovering the conductive layer in a pattern by removing uncured photocrosslinkable resin layers on the first surface and the second surface,

(N) removing the uncovered conductive layer on the first surface and the second surface by etching with an etchant, and

(O) removing the etching resist layer and the photocrosslinking cured photocrosslinkable resin layer,

in this order, subsequently to the steps (A) to (H) according to claim 15.

17. The method for producing a circuit board according to claim 15, wherein the first resin layer is a photocrosslinkable resin and the treatment for provision of resistance is an exposure treatment.

18. The method for producing a circuit board according to claim 16, wherein the etching resist layer is a metal layer insoluble in the etchant for the conductive layer and is formed by pattern plating.

19. The method for producing a circuit board according to claim 15, wherein the step (E) is performed before the step (D).

20. The method for producing a circuit board according to claim 15, wherein the step (E) is performed after the step (F).

21. A method for producing a circuit board, comprising the steps of

(α

) preparing an insulating substrate having a through-hole(s), which has a conductive layer on a first surface, on a second surface opposite to the first surface and on an inner wall of the through-hole(s),

(β

) covering the conductive layer and an opening of the through-hole(s) on the first surface with a photocrosslinkable resin layer and a mask layer by forming the photocrosslinkable resin layer and the mask layer on the first surface,

(γ

) uncovering the conductive layer on a periphery of the through-hole(s) on the first surface by supplying a photocrosslinkable resin layer removing solution from the second surface and removing the photocrosslinkable resin layer on the through-hole(s) and on the periphery of the through-hole(s) on the first surface,

(δ

) photocrosslinking curing the photocrosslinkable resin layer on the first surface in a pattern by pattern exposure,

(ε

) covering the conductive layer and an opening of the through-hole(s) on the second surface with a photocrosslinkable resin layer and a mask layer by forming the photocrosslinkable resin layer and the mask layer on the second surface,

(ζ

) removing the mask layer on the first surface,

(η

) uncovering the conductive layer on the first surface and the conductive layer on a periphery of the through-hole(s) on the second surface by supplying a photocrosslinkable resin layer removing solution from the first surface and removing an uncured photocrosslinkable resin layer on the first surface and the photocrosslinkable resin layer on the through-hole(s) and on the periphery of the through-hole(s) on the second surface,

(θ

) photocrosslinking curing the photocrosslinkable resin layer on the second surface in a pattern by pattern exposure,

(ι

) removing the mask layer on the second surface,

(κ

) uncovering the conductive layer on the second surface by supplying a photocrosslinkable resin layer removing solution from the second surface and removing an uncured photocrosslinkable resin layer on the second surface,

(λ

) forming an etching resist layer on the conductive layer uncovered on the inner wall of the through-hole(s) and the periphery of the through-hole(s) and on the first surface and the second surface,

(μ

) uncovering the conductive layer on the first surface and the second surface by removing the photocrosslinking cured photocrosslinkable resin layers on the first surface and the second surface,

(ν

) removing the uncovered conductive layer by etching, and

(ξ

) removing the etching resist layer in this order.

22. The method for producing a circuit board according to claim 21, wherein the step (ζ

) is performed before the step (ε

).

23. The method for producing a circuit board according to claim 21, wherein the step (ζ

) is performed before the step (δ

).

24. The method for producing a circuit board according to claim, wherein the step (η

) comprises the steps of (η

1) uncovering the conductive layer on the first surface by supplying a photocrosslinkable resin layer removing solution from the first surface and removing the uncured photocrosslinkable resin layer on the first surface and (η

2) uncovering the conductive layer on the periphery of the through-hole(s) on the second surface by supplying a photocrosslinkable resin layer removing solution from the first surface and removing the photocrosslinkable resin layer on the through-hole(s) and on the periphery of the through-hole(s) on the second surface, and the step (ε

) is performed between the step (η

1) and the step (η

2).