Semiconductor device package and method of manufacture
View Patent ↗A structure and method to improve saw singulation quality and wettability of integrated circuit packages ( 140 ) assembled with lead frames ( 112 ) having half-etched recesses ( 134 ) in leads. A method of forming a semiconductor device package includes providing a lead frame strip ( 110 ) having a plurality of lead frames. Each of the lead frames includes a depression ( 130 ) that is at least partially filled with a material ( 400 ) prior to singulating the strip.
1. A method, comprising:
providing a lead frame strip that has a bottom surface and a top surface, the lead frame strip including a plurality of lead frames, wherein the lead frame strip includes at least one depression in the lead frame strip, the at least one depression sized such that it does not cause an opening to occur between the bottom surface and the top surface, wherein the at least one depression becomes, after singulation of the lead frame strip into individual lead frames, at least one recess at a corner of an end of a lead of a lead frame;
filling the at least one depression with a material other than a solder wettable material; and
singulating the lead frame strip into individual lead frames while the at least one depression is substantially filled with the material.
2. The method of claim 1 , wherein the material is not removed after the step of singulating.
3. The method of claim 1 , including, prior to the step of filling the at least one depression with the material:
encapsulating the strip with a mold compound.
4. The method of claim 1 , including, after the step of filling the at least one depression with the material:
encapsulating the strip with a mold compound.
5. The method of claim 2 , including, after the step of singulating, steps of:
producing a semiconductor device package including an individual lead frame; and
mounting the semiconductor device package to a support,
wherein the material remains in the recess until the semiconductor device package is mounted to the support.
6. The method of claim 1 , in which the material is a material from a group consisting of: an adhesive material, a thermoplastic material and a polymer material.
7. The method of claim 6 , in which the material is the polymer material.
8. The method of claim 7 , wherein the polymer material is a polyvinylpyrrolidone polymer, and wherein the polyvinylpyrrolidone polymer is made one of rigid and at least semi-rigid by exposing the polyvinylpyrrolidone polymer to ultra-violent light.
9. The method of claim 1 , wherein the material is soluble in water that is above room temperature.
10. The method of claim 9 , in which the material is a thermosetting polymer material.
11. The method of claim 1 , in which the material is polyimide, and in which the polyimide is removed, using acetone, after singulating.
12. The method of claim 6 , wherein the material is fluidic during the step of filling, and wherein the material is one of rigid and at least semi-rigid during the step of singulating.
13. The method of claim 12 , wherein the material is made fluidic by heating to a temperature higher than room temperature.
14. The method of claim 12 , wherein the material is made one of rigid and at least semi-rigid by cooling to room temperature.
15. The method of claim 6 , wherein the material is removed from the individual lead frames after the step of singulating.
16. A lead frame strip, comprising:
a plurality of lead frames each of which includes:
an outer frame structure defining a central opening;
a die pad disposed within the central opening; and
a plurality of leads attached to the outer frame and extending inward toward the die pad in spaced relation to each other,
wherein each lead of one lead frame extends outward from its die pad and is integral with a lead that extends outward from a die pad of an adjacent lead frame,
wherein each of the leads includes an elongated partially-etched depression having a middle portion and two end portions, each of the two end portions becoming, after singulation of the lead frame strip into individual lead frames, a recess at a corner of an end of a lead, and wherein the elongated partially-etched depression is filled with a material prior to singulation.
17. The lead frame strip of claim 16 , wherein the material is solder.
18. A method, comprising:
providing a lead frame strip that has a bottom surface and a top surface, the lead frame strip including a plurality of lead frames;
etching at least one depression in the lead frame strip, the etching limited such that it does not create an opening between the bottom surface and the top surface, wherein the at least one depression becomes, after singulation of the lead frame strip into individual lead frames, at least one recess at a corner of an end of a lead of a lead frame;
filling the at least one depression with a removable material that is soluble in water that is above room temperature; and
singulating the lead frame strip into individual lead frames while the at least one depression is substantially filled with the material.
19. The method of claim 18 , wherein the removable material is a removable material from a group consisting of:
an adhesive material, a thermoplastic material and a thermosetting polymer material.