Methods of making stackable wiring board having electronic component in dielectric recess
A method of making a stackable wiring board is characterized by positioning an electronic component in a dielectric recess to realize the thickness reduction of the wiring board and sidewalls of the recess can confine the dislocation of the electronic component to avoid misalignment between buildup circuitry and the electronic component. An array of metal posts that provide vertical electrical connections are formed by using the same metal carrier that forms the recess, so that the predetermined distance and relative location between metal posts and pads/bumps of the electronic component can be maintained.
1. A method of making a stackable wiring board, comprising:
providing a metal carrier having substantially parallel first and second surfaces in opposite first and second directions, respectively;
forming a protruded metal platform from the first surface of the metal carrier;
forming a dielectric base covering the protruded metal platform and the remaining first surface of the metal carrier, wherein the dielectric base has a first surface apart from the metal carrier and substantially parallel to the first and second surfaces of the metal carrier and an opposite second surface adjacent to the metal carrier;
forming an array of metal posts over the second surface of the dielectric base by removing a portion of the metal carrier;
forming a recess in the dielectric base by removing the protruded metal platform and a corresponding portion of the metal carrier, wherein the corresponding portion of the metal carrier covers the protruded platform in the second direction, and the recess has a floor that is substantially parallel to the first surface of the dielectric base and a periphery defining interior sidewalls that extend from the floor to the second surface of the dielectric base;
attaching an electronic component in the recess of the dielectric base by an adhesive, wherein the electronic component protrudes out from the recess and is substantially coplanar with the metal posts in the second direction, and the sidewalls of the recess confine the dislocation of the electronic component laterally; and
forming a first buildup circuitry over the first surface of the dielectric base from the first direction and a second buildup circuitry over the electronic component and the metal posts from the second direction, wherein one of the first and second buildup circuitries is electrically coupled to the electronic component, and the first buildup circuitry is electrically connected to the second buildup circuitry and includes conductive vias in the dielectric base.
2. The method of claim 1 , further comprising a step of forming a metal layer on the floor of the recess before the step of attaching the electronic component in the recess, wherein the metal layer is thermally coupled to the first buildup circuitry through additional conductive vias in the dielectric base.
3. The method of claim 1 , further comprising a step of forming an array of auxiliary metal pads from the first surface of the metal carrier before the step of forming the dielectric base, wherein the dielectric base also covers the auxiliary metal pads from the first direction, and the metal posts are formed on the auxiliary metal pads.
4. The method of claim 3 , wherein the auxiliary metal pads have a thickness substantially equal to that of the protruded metal platform.
5. The method of claim 1 , further comprising a step of forming a stiffener that covers the second surface of the dielectric base and sidewalls of the metal posts and the corresponding portion of the metal carrier before the step of forming the recess.