Process of forming an electronic device including a polymer support layer
A process can be used to allow processing of thin layers of a workpiece including dies. The workpiece can include a base substrate and a plurality of layers overlying the base substrate. The process can include forming a polymer support layer over the plurality of layers; thinning or removing the base substrate within a component region of the workpiece, wherein the component region includes an electronic device; and singulating the workpiece into a plurality of dies after thinning or removing the base substrate. In another aspect, an electronic device can be formed using such process. In an embodiment, the workpiece may have a size corresponding to a semiconductor wafer to allow wafer-level, as opposed to die-level, processing.
1. A process comprising:
providing a workpiece having a first major surface and a second major surface opposite the first major surface, wherein the workpiece includes:
a base substrate; and
a plurality of layers overlying the base substrate, wherein the plurality of layers is closer to the first major surface than the second major surface;
forming a spacer structure overlying the plurality of layers;
forming a first polymer support layer along the first major surface of the workpiece and over the spacer structure, wherein no trench is formed within the substrate between forming the spacer structure and forming the first polymer support layer;
removing at least 50% of a thickness of the base substrate within a component region of the workpiece, wherein:
the component region includes an electronic device,
during removing at least 50% of the thickness of the base substrate, all of the spacer structure is covered by the first polymer support layer, and
after removing at least 50% of the thickness of the base substrate, a combined thickness of the workpiece and the first polymer support layer within the component region is at least 30 microns; and
singulating the workpiece into a plurality of dies after removing at least 50% of the thickness of the base substrate.
2. The process of claim 1 , wherein the first polymer support layer is permanently attached to the first major surface.
3. The process of claim 1 , further comprising removing at least a portion of the first polymer support layer to expose the spacer structure after removing at least 50% of the thickness of the base substrate.
4. The process of claim 1 , further comprising forming a second polymer support layer along the second major surface after removing at least 50% of the thickness of the base substrate and before singulating the workpiece.
5. The process of claim 3 , wherein:
providing the workpiece comprises providing the workpiece, wherein the base substrate is a wafer and has a diameter in a range of 200 mm to 400 mm,
forming the spacer structure comprises forming electrically conductive members that are electrically connected to terminals of a high electron mobility transistor, wherein the electrically conductive members have a height of at least 30 microns,
forming the first polymer support layer comprises:
forming a molding compound along the first major surface of the workpiece; and
curing the molding compound to form the first polymer support layer,
removing the portion of the first polymer support layer comprises grinding away the molding compound to expose the electrically conductive members,
removing at least 50% of a thickness of the base substrate comprises removing at least 80% of the thickness of the base substrate within the component region of the workpiece, wherein after removing at least 80% of the thickness of the base substrate, a combined thickness of the workpiece and the first polymer support layer within the component region has a thickness in a range from 75 microns to 300 microns.
6. The process of claim 1 , further comprising forming a heat sink along the second major surface of the workpiece after removing at least 50% of the thickness of the base substrate.
7. The process of claim 1 , wherein:
the base substrate is a monocrystalline Group 14 wafer, and
the plurality of layers includes a heterojunction between semiconductor layers within the component region, wherein the heterojunction has a corresponding two-dimensional charge carrier gas.
8. A process comprising:
providing a workpiece having a first major surface and a second major surface opposite the first major surface, wherein the workpiece includes:
a base substrate; and
a plurality of layers overlying the base substrate, wherein the plurality of layers is closer to the first major surface than the second major surface;
forming a polymer support layer along the first major surface of the workpiece;
removing at least 50% of a thickness of the base substrate within a component region of the workpiece, wherein:
removing the at least 50% of the thickness of the base substrate is performed using a first removal technique and a second removal technique that is different from the first removal technique,
the first removal technique is terminated before the polymer support layer is exposed, and
the component region includes an electronic device, and after removing at least 50% of the thickness of the base substrate, a combined thickness of the workpiece and polymer support layer within the component region is at least 30 microns; and
singulating the workpiece into a plurality of dies after removing at least 50% of the thickness of the base substrate.
9. The process of claim 8 , wherein the plurality of layers further includes a bond pad, and the process further comprises selectively removing a portion of the first polymer support layer to expose the bond pad.
10. The process of claim of 8 , wherein the second removal technique removes the base substrate selectively to the polymer support layer.
11. The process of claim of 8 , wherein the first removal technique includes grinding away a portion of the base substrate and is terminated before any material other than the base substrate is exposed along the second major surface of the workpiece.
12. The process of claim of 11 , wherein the second removal technique includes etching the base substrate, wherein etching the substrate is performed after the first removal technique.
13. The process of claim 8 , wherein after using the first removal technique and before using the second removal technique, the polymer support layer is not exposed along the second major surface.
14. The process of claim 8 , further comprising forming a spacer structure over the plurality of layers before forming the polymer support layer.
15. A process comprising:
providing a workpiece having a first major surface and a second major surface opposite the first major surface, wherein the workpiece includes:
a base substrate including a monocrystalline Group 14 wafer; and
a plurality of layers overlying the base substrate, wherein the plurality of layers is closer to the first major surface than the second major surface, and the plurality of layers is part of a high-electron mobility transistor;
forming a first polymer support layer along the first major surface of the workpiece;
removing at least a portion of the base substrate within a component region of the workpiece to expose a layer within the plurality of layers, wherein after removing at least a portion of the base substrate, a combined thickness of the workpiece and the first polymer support layer within the component region is at least 30 microns; and
singulating the workpiece into a plurality of dies after removing at least a portion of the base substrate,
wherein a portion of the first polymer support layer remains in a finished device.
16. The process of claim of 15 , wherein when singulating the workpiece is performed, within the component region, the base substrate has a thickness less than 75 microns.
17. The process of claim of 15 , wherein removing at least a portion of the base substrate is performed such that all of the base substrate is removed before singulating the workpiece.
18. The process of claim of 15 , further comprising forming a second polymer support layer along the second major surface after removing at least a portion of the base substrate and before singulating the workpiece.
19. The process of claim 18 , further comprising reducing a thickness of the first polymer support layer after forming the second polymer support layer and before singulating the workpiece.
20. The process of claim 18 , further comprising:
forming a spacer structure over the plurality of layers before forming the first polymer support layer; and
removing at least a portion of the first polymer support layer after forming the second polymer support layer and before singulating the workpiece.