Semiconductor structure and manufacturing method thereof
The present disclosure provides a semiconductor structure, including a first semiconductor device having a first surface and a second surface, the second surface being opposite to the first surface, a semiconductor substrate over the first surface of the first semiconductor device, and a III-V etch stop layer in contact with the second surface of the first semiconductor device. The present disclosure also provides a manufacturing method of a semiconductor structure, including providing a temporary substrate having a first surface, forming a III-V etch stop layer over the first surface, forming a first semiconductor device over the etch stop layer, and removing the temporary substrate by an etching operation and exposing a surface of the III-V etch stop layer.
1. A method of fabricating a semiconductor structure, comprising:
providing a first substrate comprising a semiconductor material and having a first surface and a second surface, the second surface being opposite to the first surface;
growing a III-V etch stop layer over and in contact with the first surface of the first substrate, wherein the growing the III-V etch stop layer does not intentionally dope the III-V etch stop layer;
forming a device layer on the III-V etch stop layer, wherein the forming the device layer includes:
forming a sensing region interfacing the III-V etch stop layer; and
forming an isolation region on each side of the sensing region;
bonding a second substrate to the first substrate including the device layer;
removing the first substrate while the second substrate is bonded to the device layer, wherein the removal includes:
thinning the first substrate by grinding the first substrate; and
after the thinning, etching the semiconductor material of the thinned first substrate to expose a surface of the III-V etch stop layer; and
forming a layer on the exposed surface of the III-V etch stop layer.
2. The method of claim 1 , wherein the forming the device layer includes forming a multilayer interconnect (MLI) including a plurality of conductive features disposed in an interlayer dielectric (ILD).
3. The method of claim 2 , wherein the bonding the second substrate to the device layer includes forming an interface between the second substrate to the ILD of the device layer.
4. The method of claim 1 , wherein the growing the III-V etch stop layer comprises growing undoped gallium phosphide (GaP).
5. The method of claim 1 , wherein the bonding the second substrate to the first substrate including the device layer includes forming an interface between the device layer and the second substrate.
6. The method of claim 1 , wherein the sensing region is a light-sensing region and the forming the layer on the exposed surface includes forming a color filter aligned with the light-sensing region.
7. The method of claim 6 , further comprising:
forming a lens over the color filter.
8. The method of claim 7 , wherein a light sensing region is disposed within the device layer vertically aligned with the III-V etch stop layer, the color filter and the lens.
9. The method of claim 1 , wherein the etching the semiconductor material is selective between the semiconductor material and the III-V etch stop layer such that the etching is stopped at a surface of the III-V etch stop layer.
10. The method of claim 1 , wherein the etching includes a basic etchant of tetramethylammonium hydroxide (TMAH).
11. The method of claim 1 , wherein the providing the first substrate a trilayer of the semiconductor material, an oxide, and another semiconductor material.
12. The method of claim 1 , wherein the thinning the first substrate includes a wet etching process followed by at least one of a coarse grinding and a fine grinding.
13. The method of claim 1 , wherein the removing the first substrate further comprises: prior to the grinding, performing a wet etching using hydrochloric acid, nitric acid, and acetic acid.
14. A method of fabricating a semiconductor structure, comprising:
providing a first substrate comprising silicon and having a first surface and a second surface, the second surface being opposite to the first surface;
growing an undoped gallium phosphide (GaP) layer over and in contact with the first surface of the first substrate, wherein the first surface is silicon;
forming a device layer on the undoped GaP layer;
bonding a second substrate to the first substrate including the device layer;
removing the first substrate while the second substrate is bonded to the device layer, wherein the removal includes:
thinning the first substrate by grinding the first substrate; and
after the thinning, etching the silicon of the thinned first substrate to expose a surface of the undoped GaP layer; and
forming a layer on the exposed surface of the undoped GaP layer.
15. The method of claim 14 , wherein the forming the device layer includes: forming a light-sensing region, a plurality of transistors, and a multilayer interconnect (MLI), wherein the light-sensing region interfaces the undoped GaP layer.
16. The method of claim 14 , wherein the forming the layer on the exposed surface of the undoped GaP layer includes depositing a dielectric material directly on the exposed surface.
17. The method of claim 16 , further comprising:
forming a through silicon via extending through the dielectric material and the undoped GaP layer.
18. A method of fabricating a semiconductor structure, comprising:
providing a first substrate comprising a stack of a semiconductor material, another semiconductor material, and an oxide, wherein the first substrate has a first surface of the semiconductor material and a second surface of the oxide, the second surface being opposite to the first surface, wherein the semiconductor material and the another semiconductor material have a different dopant concentration;
growing a III-V etch stop layer over and in contact with the first surface of the first substrate, wherein the growing the III-V etch stop layer does not intentionally dope the III-V etch stop layer;
forming a device layer on the III-V etch stop layer;
bonding a second substrate to the first substrate including the device layer;
removing the first substrate while the second substrate is bonded to the device layer, wherein the removal includes:
thinning the first substrate by grinding the first substrate to remove the oxide and the another semiconductor material; and
after the thinning, etching the semiconductor material of the thinned first substrate to expose a surface of the III-V etch stop layer; and
forming a layer on the exposed surface of the III-V etch stop layer.
19. The method of claim 18 , wherein the growing the III-V etch stop layer over and in contact with the first surface of the first substrate includes growing an undoped gallium phosphide (GaP) layer in contact with the first surface of the semiconductor material, the semiconductor material being silicon.
20. The method of claim 18 , wherein the forming the device layer includes: forming a light-sensing region, a plurality of transistors, and a multilayer interconnect (MLI), wherein the light-sensing region interfaces the III-V etch stop layer.