Method of manufacturing a device with a cavity
The invention relates to a micro-device with a cavity, the micro-device comprising a substrate, the method comprising steps of: A) providing the substrate, having a surface and comprising a sacrificial oxide region at the surface; B) covering the sacrificial oxide region with a porous layer being permeable to a vapor HF etchant, and C) selectively etching the sacrificial oxide region through the porous layer using the vapor HF etchant to obtain the cavity. This method may be used in the manufacture of various micro-devices with a cavity, i.e. MEMS devices, and in particular in the encapsulation part thereof, and semiconductor devices, and in particular the BEOL-part thereof.
1. A method of manufacturing a Microelectromechanical Systems (MEMS) device with an element that is moveable in operational use of the MEMS device, the MEMS device comprising a substrate, the method comprising:
providing the substrate comprising a first sacrificial oxide region, the substrate comprising the element embedded between the first sacrificial oxide region and a second sacrificial oxide region in contact with the first sacrificial oxide region
covering the first sacrificial oxide region with a porous material to form a porous layer, the porous material being permeable to a vapor HF etchant, and
releasing the element by selectively etching the first and second sacrificial oxide regions through the porous layer using the vapor HF etchant;
wherein the porous layer comprises a non-densified carbon doped oxide.
2. The method of claim 1 , wherein covering the first sacrificial oxide region with the porous layer is not followed by a plasma treatment of the porous layer before the selectively etching.
3. The method of claim 1 , further comprising:
between the step of providing the substrate and the step of covering the first sacrificial oxide region, covering the substrate with a packaging cap layer and patterning the packaging cap layer to form a release hole in the packaging cap layer over the porous layer;
wherein selectively etching, includes etching the porous layer through the release hole.
4. The method of claim 1 , wherein the method omits a packaging cap layer under the porous layer.
5. The method of claim 3 , wherein the step of patterning the packaging cap layer includes forming the release hole directly above the element.
6. The method of claim 1 , further including:
applying a plasma treatment to the porous layer after releasing the element; and
forming a sealing layer over the porous layer.
7. A method of manufacturing a Microelectromechanical Systems (MEMS) device with an element that is moveable in operational use of the MEMS device, the MEMS device comprising a substrate, the method comprising:
providing the substrate comprising a first interconnect layer, the first interconnect layer comprising a first sacrificial oxide region, the substrate comprising the element embedded between the first sacrificial oxide region and a second sacrificial oxide region in contact with the first sacrificial oxide region;
covering the first sacrificial oxide region with a porous material to form a first porous layer, the porous material being permeable to a vapor HF etchant, the porous material comprising a non-densified carbon doped oxide; and
releasing the element by selectively etching the first and second sacrificial oxide regions through the porous layer using the vapor HF etchant.
8. The method of claim 7 , further comprising:
creating a second interconnect layer over the first interconnect layer, wherein the second interconnect layer comprises the second sacrificial oxide region;
covering the second sacrificial oxide region with a second porous layer, wherein the first and second sacrificial oxide regions are separated by the second porous layer, further wherein the second porous layer is permeable to a vapor HF etchant; and
selectively etching the first and second sacrificial oxide regions through the first and second porous layers using the vapor HF etchant.
9. The method of claim 7 , wherein covering the first and second sacrificial oxide regions is not followed by plasma treatment of the first and second porous layers before the selectively etching.
10. The method of claim 7 , wherein covering the first and second sacrificial oxide regions is not preceded by plasma treatment of the first or second sacrificial oxide regions.
11. The method of claim 7 , wherein the selectively etching comprises a single etch step to etch both the first and second sacrificial oxide regions.
12. A method of manufacturing a Microelectromechanical Systems (MEMS) device with an element that is moveable in operational use of the MEMS device, the MEMS device comprising a substrate, the method comprising:
providing the substrate comprising a first sacrificial oxide region, the substrate comprising the element embedded between the first sacrificial region and a second sacrificial region in contact with the first sacrificial region;
covering the first sacrificial region with a porous layer being permeable to a vapor HF etchant; and
releasing the element by selectively etching the first and second sacrificial regions through the porous layer using the vapor HF etchant;
wherein the porous layer comprises a non-densified carbon doped oxide.
13. The method of claim 12 , wherein covering the first sacrificial region with the porous layer is not followed by a plasma treatment of the porous layer before the selectively etching.
14. The method of claim 12 , further comprising:
between the step of providing the substrate and the step of covering the first sacrificial region, covering the substrate with a packaging cap layer and patterning the packaging cap layer to form a release hole in the packaging cap layer over the porous layer;
wherein selectively etching, includes etching the porous layer through the release hole.
15. The method of claim 12 , wherein the first and second sacrificial regions include oxides.