Semiconductor device and method of manufacturing the same
A GaN layer and an n-type AlGaN layer are formed over an insulating substrate, and thereafter, a gate electrode, a source electrode and a drain electrode are formed on them. Next, an opening reaching at least a surface of the insulating substrate is formed in the source electrode, the GaN layer and the n-type AlGaN layer. Then, a nickel (Ni) layer is formed in the opening. Thereafter, by conducting dry etching from the back side while making the nickel (Ni) layer serve as an etching stopper, a via hole reaching the nickel (Ni) layer is formed in the insulating substrate. Then, a via wiring is formed extending from an inside the via hole to the back surface of the insulating substrate.
1. A method of manufacturing a semiconductor device, comprising:
forming a compound semiconductor layer over a substrate;
forming a gate electrode, a source electrode and a drain electrode on said compound semiconductor layer;
forming a passivation film covering said gate electrode, said source electrode and said drain electrode;
forming an opening penetrating said passivation film and reaching at least a surface of said substrate in said compound semiconductor layer;
forming a first metal layer containing tantalum (Ta) or tantalum nitride (TaN) in said opening;
forming a conductive layer coupled to said source electrode on said first metal layer in said opening;
conducting dry etching from a back side of said substrate while making said conductive layer serve as an etching stopper so as to form a via hole reaching said conductive layer; and
forming a via wiring extending from an inside of said via hole to a back surface of said substrate.
2. The method of manufacturing a semiconductor device according to claim 1 , wherein a gas containing fluorine is used in conducting said dry etching.
3. The method of manufacturing a semiconductor device according to claim 1 , wherein forming said opening comprises etching said compound semiconductor layer using a gas containing chlorine.
4. The method of manufacturing a semiconductor device according to claim 1 , wherein said conductive layer contains nickel (Ni).
5. The method of manufacturing a semiconductor device according to claim 1 , wherein said substrate contains silicon carbide (SiC).
6. The method of manufacturing a semiconductor device according to claim 1 , further comprising, between forming said conductive layer and forming said via hole, forming a metal mask on the back surface of said substrate.
7. The method of manufacturing a semiconductor device according to claim 6 , wherein said metal mask contains nickel (Ni).
8. The method of manufacturing a semiconductor device according to claim 6 , further comprising, before forming said metal mask, forming a second metal layer on the back surface of said substrate,
wherein said metal mask is formed over said second metal layer.
9. The method of manufacturing a semiconductor device according to claim 8 , wherein said second metal layer contains metal having a melting point higher than titanium (Ti).
10. A method of manufacturing a semiconductor device, comprising:
forming a compound semiconductor layer over an insulating substrate;
forming a gate electrode, a source electrode and a drain electrode on said compound semiconductor layer;
forming a passivation film covering said gate electrode, said source electrode and said drain electrode;
forming an opening penetrating said passivation film and reaching at least a surface of said insulating substrate in said source electrode and said compound semiconductor layer;
forming a first metal layer containing tantalum (Ta) or tantalum nitride (TaN) in said opening;
forming a conductive layer on said first metal layer in said opening;
conducting dry etching from a back side of said insulating substrate while making said conductive layer serve as an etching stopper so as to form a via hole reaching said conductive layer; and
forming a via wiring extending from an inside of said via hole to a back surface of said insulating substrate.
11. The method of manufacturing a semiconductor device according to claim 10 , wherein a gas containing fluorine is used in conducting said dry etching.
12. The method of manufacturing a semiconductor device according to claim 10 , further comprising, between forming said conductive layer and forming said via hole, forming a metal mask on the back of said insulating substrate.
13. The method of manufacturing a semiconductor device according to claim 10 , wherein forming said via wiring comprises forming a copper (Cu) layer.