Wiring glass substrate for connecting a semiconductor chip to a printed wiring substrate and a semiconductor module having the wiring glass substrate
A wiring glass substrate includes a glass substrate formed of glass and having a plurality of holes formed at predetermined positions, bumps so formed as to be connected to a conductive material filling the holes and wirings formed on a surface opposite to a surface having the bumps formed thereon and electrically connecting a plurality of connection terminals arranged in intervals different from intervals of the holes to the conductive material. The shape of the conductive material is porous and porous electrodes are bonded to the inner wall surfaces of the holes by an anchor effect to increase the strength of the glass substrate.
1. A wiring glass substrate for connecting a semiconductor chip to a printed wiring substrate, comprising:
a substrate formed of a first glass and having a plurality of holes formed at predetermined positions wherein a section of each of the holes has a plurality of substantially round or crater-like concave convexities;
bumps formed on an electrically porous conductive material said electrically porous conductive material filling each of said holes, wherein a second glass having a lower softening point than said first glass is inside pores of said electrically porous conductive material or on a surface of said electrically porous conductive material; and
wirings formed on a surface opposite to a surface on which said bumps are formed, for electrically connecting a plurality of connection terminals arranged with intervals different from intervals of said holes to said electrically porous conductive material;
wherein a shape of said conductive material is porous.
2. A wiring glass substrate according to claim 1 , wherein said electrically porous conductive material forms a heat radiation route.
3. A wiring glass substrate according to claim 1 , wherein in each of said holes, a porous electrode being formed by said electrically porous conductive material and an oxide layer or an additional glass layer are arranged therein.
4. A wiring glass substrate according to claim 1 , wherein an oxide film is formed on an entire surface of said substrate, wirings are formed on said oxide film, and a section of said holes connecting said two opposing wiring surfaces is constituted by said oxide film and a porous electrode being formed by said electrically porous conductive material.
5. A wiring glass substrate according to claim 1 , further comprising said second glass having the softening point lower than said first glass on inner wall surfaces of said holes.
6. A wiring glass substrate according to claim 5 , wherein an oxide exists on a surface of said holes.
7. A wiring glass substrate according to claim 6 , wherein said oxide being on inner wall surfaces of said holes and said second glass being on a surface of said oxide.
8. A wiring glass substrate according to claim 6 , wherein a Na compound exists on surfaces of said holes.
9. A wiring glass substrate according to claim 8 , which contains Na and wherein said oxide exists on surfaces or cracks of said holes.
10. A wiring glass substrate according to claim 5 , wherein sizes of two open portions of said through-holes are different and have a taper angle on inner walls of said holes.
11. A semiconductor module having said wiring glass substrate according to claim 1 , wherein said wiring glass substrate having said semiconductor chip mounted thereto is connected to said printed wiring substrate.