1. A vacuum filtration apparatus comprising:
a base including an outlet port capable of being adapted to a vacuum source, a filter seal surface disposed above said outlet port, and a pad well,
said pad well containing a substantially vertical side wall and a bottom wall, with the boundary of the top of the side wall of the pad well being coincident with the inner boundary of the filter seal surface, with the bottom wall of the pad well being substantially parallel to the filter seal surface, and disposed entirely below the filter seal surface,
an absorbent pad disposed in said pad well, with the downstream surface of said absorbent pad resting directly on the bottom wall of the pad well,
a filter means, with the downstream surface of the outer periphery of the filter means in direct contact with the filter seal surface of the base, with the outer periphery of the filter means sealed to the vacuum filtration apparatus to prevent the flow of un-filtered liquid between the filter seal surface of the base and the downstream surface of the outer periphery of the filter means, with the portion of the downstream surface of the filter means disposed inside of the filter seal surface of the base disposed above the top surface of the absorbent pad, thereby creating a gap between the portion of the downstream surface of the filter means disposed inside of the filter seal surface of the base and the top surface of the absorbent pad, when both the filter means and the absorbent pad are dry,
a funnel with an open top disposed above the filter seal surface of the base, said funnel forming a reservoir capable of holding un-filtered liquid upstream of the filter means,
with the height of the gap between the downstream surface of the dry filter means and the upstream surface of the dry absorbent pad having a value such that when a differential pressure is applied between the upstream of the filter means, after the filter means has been wetted, and the downstream of the absorbent pad, after the absorbent pad has been wetted, the differential pressure will force a central portion of the wetted filter means downward into a concave dish shape until the downstream surface of the central portion of the wetted filter means is resting flat on the upstream surface of the wetted absorbent pad, with the upstream surface of the central portion of the wetted filter means disposed below the filter seal surface of the base, with the downstream surface of the outer periphery of the wetted filter means resting on the filter seal surface of the base, and with the portion of the downstream surface of the wetted filter means between the central portion and the outer periphery substantially conforming to the side wall of the pad well of the base, so that any wrinkles caused by the swelling of the wetted filter means are removed, without causing the wetted filter means to be stretched by the differential pressure.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A surface acoustic wave device comprising:
a surface acoustic wave substrate;
at least one interdigital electrode disposed on said surface acoustic wave substrate, said at least one interdigital electrode including a first comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, a second comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, and first and second wiring electrode portions which include lead electrodes which are electrically connected to the first and the second comb-like electrode portions, respectively, a plurality of bumps, and bonding pads which are connected to an external environment via the plurality of bumps, the electrode fingers of the first and the second comb-like electrode portions being interdigitated with each other, the first and the second comb-like electrode portions and the first and the second wiring electrode portions including an aluminum film; and
first, second and third metal films which are laminated on each of the first and second wiring electrode portions in the order of the first metal film, the second metal film, and the third metal film, the first metal film being more bondable to aluminum than the second metal film, the third metal film being more bondable to the plurality of bumps than the first metal film, and the second metal film having an ability to suppress the diffusion of metals defining the first metal film and the third metal film.
2. A surface acoustic wave device according to claim 1, further comprising a reaction suppressing film which is disposed between the aluminum film and the first metal film for suppressing a reaction between the aluminum film and a laminate including the second metal film and the third metal film.
3. A surface acoustic wave device according to claim 1, wherein the first metal film comprises at least one material selected from the group consisting of Ti, Cr, Ni, Hf, and alloys thereof.
4. A surface acoustic wave device according to claim 1, wherein the second metal film comprises at least one material selected from the group consisting of Pd, Pt, Ni, Cu, and alloys thereof.
5. A surface acoustic wave device according to claim 1, wherein the third metal film comprises at least one material selected from the group consisting of Ag, Au, and alloys thereof.
6. A surface acoustic wave device according to claim 2, wherein said reaction suppressing film is made of the same material as a material used to form the first metal film.
7. A surface acoustic wave device according to claim 2, wherein said reaction suppressing film is made of an inorganic, insulative material, and wherein the first, second and third metal films are electrically connected to the aluminum film.
8. A surface acoustic wave device according to claim 7, wherein said reaction suppressing film that is made of the inorganic, insulative material is provided with a through hole, via which the first, second and third metal films are electrically connected to the aluminum film.
9. A surface acoustic wave device according to claim 2, wherein said reaction suppressing film comprises at least one material selected from the group consisting of Ti, Cr, and alloys thereof.
10. A surface acoustic wave device according to claim 9, wherein said reaction suppressing film is arranged such that the periphery thereof is outside the periphery of a laminate including the first, second and third metal films.
11. A surface acoustic wave device according to claim 1, wherein the plurality of bumps are made of Au.
12. A surface acoustic wave device according to claim 1, wherein the first, second and third metal films are disposed on the bonding pads and a lead electrode.
13. A surface acoustic wave device according to claim 2, wherein a step is provided between the reaction suppressing film and one of a first laminate including each of the first, second and third metal films, and a second laminate including the second and third metal films.
14. A surface acoustic wave device according to claim 2, wherein the reaction suppressing film extend beyond the peripheries of the wiring electrode portions.
15. A surface acoustic wave device comprising:
a surface acoustic wave substrate;
at least two interdigital electrodes disposed on said surface acoustic wave substrate, each of said at least two interdigital electrodes including a first comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, a second comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, and first and second wiring electrode portions which include lead electrodes which are electrically connected to the first and the second comb-like electrode portions, respectively, a plurality of bumps made of Au, and bonding pads which are connected to an external environment via the plurality of bumps, the electrode fingers of the first and the second comb-like electrode portions being interdigitated with each other, the first and the second comb-like electrode portions and the first and the second wiring electrode portions being defined by an aluminum film; and
a laminate including first, second and third metal films disposed on each of the first and second wiring electrode portions, the first metal film being more bondable to aluminum than the second metal film, the third metal film being more bondable to the plurality of bumps than the first metal film, and the second metal film having an ability to suppress the diffusion of metals defining the first metal film and the third metal film.
16. A surface acoustic wave device according to claim 15, further comprising a reaction suppressing film which is disposed between the aluminum film and the first metal film for suppressing a reaction between the aluminum film and a laminate including the second metal film and the third metal film.
17. A surface acoustic wave device according to claim 15, wherein the first metal film comprises at least one material selected from the group consisting of Ti, Cr, Ni, Hf, and alloys thereof, the second metal film comprises at least one material selected from the group consisting of Pd, Pt, Ni, Cu, and alloys thereof, and the third metal film comprises at least one material selected from the group consisting of Ag, Au, and alloys thereof.
18. A surface acoustic wave device according to claim 16, wherein said reaction suppressing film is made of the same material as a material used to form the first metal film.
19. A surface acoustic wave device according to claim 16, wherein said reaction suppressing film is made of an inorganic, insulative material, and wherein the first, second and third metal films are electrically connected to the aluminum film.
20. A surface acoustic wave device according to claim 19, wherein said reaction suppressing film that is made of the inorganic, insulative material is provided with a through hole, via which the first, second and third metal films are electrically connected to the aluminum film.
21. A surface acoustic wave device according to claim 16, wherein said reaction suppressing film comprises at least one material selected from the group consisting of Ti, Cr, and alloys thereof.
22. A surface acoustic wave device according to claim 21, wherein said reaction suppressing film is arranged such that the periphery thereof is outside the periphery of a laminate including the first, second and third metal films.