MANUFACTURING PROCESS FOR A SURFACE-MOUNT METAL-CAVITY PACKAGE FOR AN OSCILLATOR CRYSTAL BLANK
First Claim
1. A method for making a metal surface-mount package comprising:
- etching half-etched cavities into a mounting surface of a metal sheet substrate, the half-etched cavities reaching only partially and not completely through the metal sheet substrate to an opposite surface to the mounting surface;
filling the half-etched cavities with an insulator;
forming drilled vias within the half-etched cavities wherein side edges of the drilled vias are insulator and not metal, wherein bottoms of the drilled vias reach the metal sheet substrate;
forming a contact metal layer on the bottoms of the drilled vias;
filling the drilled vias with via metal;
forming and patterning metal over the via metal and over the mounting surface to form external metal pads on the mounting surface, the external metal pads electrically contacting the via metal and the contact metal layer;
forming inner cavities in the opposite surface that each reach the contact metal layer for at least two of the drilled vias filled with via metal;
placing conductive epoxy on the contact metal layer within the inner cavities;
placing a die onto the conductive epoxy, wherein electrodes on the die make contact with the conductive epoxy; and
sealing the die within the inner cavity by covering the inner cavity with a cover;
whereby the die is packaged in the metal surface-mount package with external metal pads on the mounting surface for surface mounting the metal surface-mount package to a printed-circuit board (PCB).
4 Assignments
0 Petitions
Accused Products
Abstract
A surface-mount package for an oscillator crystal blank is made from a metal sheet substrate. Half-etched cavities are formed on one side of the sheet. The half-etched cavities are filled in with an insulator. The center of the insulator is drilled until metal is reached, leaving insulator on the sidewalls of the resulting drilled via. The bottom of the drilled via is plated with a contact metal such as nickel-gold, and then the entire drilled via is filled in with metal such as copper to form via-metal. An external metal surface-mount pad is formed on the surface of each via-metal. The metal sheet is flipped over, and a larger inner cavity etched through until the contact metal over the via-metal is reached. Conductive epoxy is placed on the contact metal, and electrodes on the crystal blank are attached to conductive epoxy.
21 Citations
20 Claims
-
1. A method for making a metal surface-mount package comprising:
-
etching half-etched cavities into a mounting surface of a metal sheet substrate, the half-etched cavities reaching only partially and not completely through the metal sheet substrate to an opposite surface to the mounting surface;
filling the half-etched cavities with an insulator;
forming drilled vias within the half-etched cavities wherein side edges of the drilled vias are insulator and not metal, wherein bottoms of the drilled vias reach the metal sheet substrate;
forming a contact metal layer on the bottoms of the drilled vias;
filling the drilled vias with via metal;
forming and patterning metal over the via metal and over the mounting surface to form external metal pads on the mounting surface, the external metal pads electrically contacting the via metal and the contact metal layer;
forming inner cavities in the opposite surface that each reach the contact metal layer for at least two of the drilled vias filled with via metal;
placing conductive epoxy on the contact metal layer within the inner cavities;
placing a die onto the conductive epoxy, wherein electrodes on the die make contact with the conductive epoxy; and
sealing the die within the inner cavity by covering the inner cavity with a cover;
whereby the die is packaged in the metal surface-mount package with external metal pads on the mounting surface for surface mounting the metal surface-mount package to a printed-circuit board (PCB). - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
8. (canceled)
-
19. A manufacturing process comprising:
-
applying a first resist to a mounting surface of a metal sheet and patterning the first resist to form first openings to the metal sheet;
etching half-etched cavities in the first openings on the mounting surface of the metal sheet;
removing the first resist and applying an insulator onto the mounting surface so that the insulator fills the half-etched cavities to form filled cavities;
drilling holes within the half-etched cavities so that the holes are surrounded by the insulator but have a depth sufficient to reach metal under the filled cavities;
filling the holes with metal to form via-metal-filled holes;
applying a metal layer to the mounting surface and patterning the metal layer into external pads on the mounting surface, wherein the external pads connect to the via-metal-filled holes;
applying a second resist to a second surface opposite the mounting surface of the metal sheet and patterning the second resist to form second openings to the metal sheet;
etching die cavities that are larger than the half-etched cavities in the second openings on the second surface of the metal sheet;
wherein the die cavities are sufficiently deep to reach the metal in the via-metal-filled holes;
applying conductive epoxy into the die cavities in the second surface, the conductive epoxy placed onto the metal in the via-metal-filled holes exposed inside the die cavities;
placing die within the die cavities so that each die contacts at least two via-metal-filled holes through the conductive epoxy; and
sealing the die cavity and separating the metal sheet into metal packages that contain die in the die cavities, but are mounted to printed-circuit boards by the external pads on the mounting surface.
-
-
20. An annular-shaped manufacturing process comprising:
-
applying a first resist to a mounting surface of a metal sheet and patterning the first resist to form first openings to the metal sheet;
etching half-etched cavities in the first openings on the mounting surface of the metal sheet;
removing the first resist and applying an insulator onto the mounting surface so that the insulator fills the half-etched cavities to form filled cavities;
wherein the half-etched cavities are annular shaped surrounding a metal island, and the metal island within the annular shape forms via-metal-filled holes;
applying a metal layer to the mounting surface and patterning the metal layer into external pads on the mounting surface, wherein the external pads connect to the via-metal-filled holes;
applying a second resist to a second surface opposite the mounting surface of the metal sheet and patterning the second resist to form second openings to the metal sheet;
etching die cavities that are larger than the half-etched cavities in the second openings on the second surface of the metal sheet;
wherein the die cavities are sufficiently deep to reach the metal in the via-metal-filled holes;
applying conductive epoxy into the die cavities in the second surface, the conductive epoxy placed onto the metal in the via-metal-filled holes exposed inside the die cavities;
placing die within the die cavities so that each die contacts at least two via-metal-filled holes through the conductive epoxy; and
sealing the die cavity and separating the metal sheet into metal packages that contain die in the die cavities, but are mounted to printed-circuit boards by the external pads on the mounting surface.
-
Specification