Wiring board

Abstract

To provide a wiring board which is less likely to be cracked by heat application.SOLUTION: A wiring board 12 comprises: a first insulating layer 1241 which has a first surface and a second surface that is a rear face thereof, and which is provided with a first through-hole R1 extending from the first surface to the second surface; a second insulating layer 1242 which is provided on the second surface, and which is provided with a second through-hole R2 communicating with the first through-hole R1, and a groove G; and a conductor layer including a via part 1244V which embeds the first through-hole R1, a land part 1244L which embeds the second through-hole R2, and a wiring part 1244W which embeds the groove G. In a region located between the land part 1244L and the wiring part 1244W, which is part of a boundary surface between the first insulating layer 1241 and the second insulating layer 1242, a position adjacent to the land part 1244L and a position away from the land part 1244L have different heights.SELECTED DRAWING: Figure 2

Claims

1. In obtaining a composite wiring board by joining a first wiring board as a wiring board for a flip-chip ball grid array and a second wiring board as an interposer by heating, the wiring board used as the second wiring board is: A first insulating layer having a first surface and a second surface which is its back surface, wherein a first through-hole extending from the first surface to the second surface is provided in the first insulating layer, A second insulating layer provided on the second surface, the second insulating layer having a second through hole communicating with the first through hole and a groove, The conductor layer comprises a via portion into which the first through hole is embedded, a land portion into which the second through hole is embedded, and a wiring portion into which the groove is embedded. The region of the interface between the first insulating layer and the second insulating layer located between the land portion and the wiring portion has different heights at positions adjacent to the land portion and positions separated from the land portion. The wiring board is provided with a recess in the first insulating layer that is open on the second surface, and the groove is open at the bottom surface of the recess.

2. The wiring board according to claim 1, wherein the position adjacent to the land portion is at a greater distance from the first surface compared to the position spaced apart from the land portion.

3. The wiring board according to claim 1 or 2, wherein the ratio D / T of the depth D of the recess to the thickness T of the first insulating layer at the position adjacent to the land portion is in the range of 0.5 to 0.

99.

4. The wiring board according to any one of claims 1 to 3, wherein a plurality of wiring portions are present within one of the recesses.

5. The wiring board according to any one of claims 1 to 4, wherein the recess is tapered in a forward direction.

6. The wiring board according to any one of claims 1 to 5, wherein the wiring portion has a constant thickness in the longitudinal direction.

7. The wiring board according to any one of claims 1 to 6, further comprising an insulating resin layer that fills the portion of the groove on the first insulating layer side, wherein the wiring portion fills the portion of the groove that is not filled with the insulating resin layer.

8. A wiring substrate according to any one of claims 1 to 7, further comprising a first metal-containing layer covering the side and bottom surfaces of the conductor layer, wherein the first metal-containing layer contains titanium.

9. The wiring substrate according to claim 8, further comprising a second metal-containing layer interposed between the first metal-containing layer and the conductor layer, the second metal-containing layer being made of the same material as the conductor layer or a metal material having a lower ionization tendency compared to the material of the conductor layer, wherein the second metal-containing layer is made of copper.

10. A composite wiring board comprising a first wiring board and a second wiring board bonded to the first wiring board, wherein the first and second wiring boards are electrically connected to each other via bonding electrodes interposed between them, and the second wiring board is a wiring board according to any one of claims 1 to 9.

11. A composite wiring board according to claim 10, A functional device mounted on the side of the second wiring board opposite to the first wiring board and A packaged device equipped with the following features.

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