Process for making laminate substrate with sintered components
The present disclosure relates to a process to integrate sintered components in a laminate substrate. The disclosed process starts with providing a precursor substrate, which includes a substrate body having an opening through the substrate body, and a first foil layer. Herein, the first foil layer is formed underneath the substrate body, so as to fully cover a bottom of the opening. Next, a sinterable base material is applied into the opening and over the first foil layer, and then sintered at a first sintering temperature to create a sintered base component. A sinterable contact material is applied over the sintered base component, and then sintered at a second sintering temperature to create a sintered contact film. The sintered base component is confined within the opening by the substrate body on sides, by the first foil layer on bottom, and by the sintered contact film on top.
1. A method comprising:
providing a precursor substrate, which includes a substrate body and a first foil layer, wherein:
the substrate body has an opening through the substrate body; and
the first foil layer is formed underneath the substrate body and extends underneath the opening, such that a first portion of the first foil layer fully covers a bottom of the opening;
applying a sinterable base material into the opening and over the first portion of the first foil layer;
applying a sinterable contact material over the sinterable base material;
sintering the sinterable base material at a first sintering temperature to create a sintered base component; and
sintering the sinterable contact material at a second sintering temperature to create a sintered contact film after sintering the sinterable base material, wherein:
the first sintering temperature is lower than the second sintering temperature; and
the sintered base component is confined within the opening by the substrate body on sides, by the first foil layer on bottom, and by the sintered contact film on top.
2. The method of claim 1 further comprising applying a second foil layer over the substrate body, wherein the second foil layer does not extend laterally over the opening.
3. The method of claim 2 wherein the second foil layer is applied after sintering the sinterable contact material to create the sintered contact film.
4. The method of claim 2 wherein the second foil layer is applied before applying the sinterable base material.
5. The method of claim 2 wherein the second foil layer is applied after applying the sinterable contact material and before sintering the sinterable base material to create the sintered base component.
6. The method of claim 2 further comprising planarizing a top surface of the sintered contact film and a top surface of the second foil layer.
7. The method of claim 2 wherein a top surface of the sintered contact film and a top surface of the second foil layer are at a same flat plane.
8. The method of claim 7 further comprising applying a surface finish over the second foil layer and the sintered contact film, wherein the surface finish is one of a group consisting of electroless nickel electroless palladium immersion gold (ENEPIG) finish, bussed nickel gold (NiAu) finish, bussless NiAu finish, and electroless nickel immersion gold (ENIG) finish.
9. The method of claim 7 further comprising applying a first surface finish underneath the first foil layer, and applying a second surface finish over the second foil layer and the sintered contact film, wherein the first surface finish is one of a group consisting of ENEPIG finish, bussed NiAu finish, bussless NiAu finish, and ENIG finish, and the second surface finish is one of the group consisting of ENEPIG finish, bussed NiAu finish, bussless NiAu finish, and ENIG finish.
10. The method of claim 1 further comprising applying a surface finish underneath the first foil layer, wherein the surface finish is one of a group consisting of the group consisting of ENEPIG finish, bussed NiAu finish, bussless NiAu finish, and ENIG finish.
11. The method of claim 1 further comprising planarizing a top surface of the sintered contact film.
12. The method of claim 1 wherein the sintered base component has a dielectric constant between 10 and 500.
13. The method of claim 1 wherein the sintered base component has a relative permeability greater than 5.
14. The method of claim 1 wherein the first sintering temperature is between 150° C. and 250° C., and the second sintering temperature is between 175° C. and 250° C.
15. The method of claim 1 wherein:
the sinterable base material includes ceramic particles mixed with a base binder material, wherein the base binder material has an evaporation temperature between 150° C. and 250° C.; and
the sinterable contact material includes metal particulates mixed with a contact binder material that has an evaporation temperature between 150° C. and 250° C., wherein the evaporation temperature of the contact binder material is higher than the evaporation temperature of the base binder material.
16. The method of claim 15 wherein the ceramic particles are selected from at least one of a group consisting of barium strontium titanate (BST), aluminum nitride, and aluminum oxide.
17. The method of claim 16 wherein the base binder material comprises at least one of a group consisting of methylcellulose, phenolic resins, polyvinyl acetate, polyvinyl alcohol, and polymethyl methacrylate.
18. The method of claim 1 wherein:
the sinterable base material includes ferro-magnetic particles mixed with a base binder material, wherein the base binder material has an evaporation temperature between 150° C. and 250° C.; and
the sinterable contact material includes metal particulates mixed with a contact binder material that has an evaporation temperature between 150° C. and 250° C., wherein the evaporation temperature of the contact binder material is higher than the evaporation temperature of the base binder material.
19. The method of claim 18 wherein the ferro-magnetic particles are selected from at least one of a group consisting of iron, nickel, cobalt, and neodymium.
20. The method of claim 19 wherein the base binder material comprises at least one of a group consisting of zinc/lithium stearates, agar, polyacetal, and water-soluble polyvinyl alcohol.