Method of forming a semiconductor device
View Patent ↗A semiconductor device is formed as part of an integrated circuit. The semiconductor device, which is formed in an active semiconductor layer, is surrounded by a guardian that provides a diffusion barrier against contaminants and also provides assistance in avoiding dishing above the semiconductor device during chemical mechanical polishing. The dielectric that is above the semiconductor device and inside the guardian is etched to form an opening that receives one of an optical fiber, an electromagnetic signal source, or an electromagnetic signal load. The remaining dielectric is in layers that are of substantially uniform thickness. The guardian is built up in layers that are part of a normal integrated circuit process. These include contact layers, via layers, and interconnect layers.
1. A method for making a semiconductor device, comprising:
providing a semiconductor substrate having an active semiconductor layer;
forming a semiconductor device in a first portion of the active semiconductor layer and forming one of a waveguide and detector in a second portion of the active semiconductor layer adjacent the first portion, wherein the semiconductor device includes regions of alternating low index of refraction and high index of refraction material form an optical grating;
forming a first dielectric layer over the semiconductor substrate;
forming a first metal layer substantially around and adjacent to the semiconductor device in the first portion of the active semiconductor layer while leaving a portion of the first dielectric layer over the semiconductor device in the first portion of the active semiconductor layer and over the waveguide or detector in the second portion of the active semiconductor layer, wherein the first metal layer includes a circular shape having one or more discontinuities, further wherein a minimal proximity of the first metal layer to the semiconductor device in the first portion of the active semiconductor layer and the waveguide or detector in the second portion of the active semiconductor layer is selected to substantially eliminate any undesirable optical interference between the same;
forming a second dielectric layer over the semiconductor layer; and
forming a second metal layer over and substantially aligned to the first metal layer and to surround an area overlying the semiconductor device in the first portion of the active semiconductor layer, the second metal layer further including a circular shape without having a discontinuity.
2. The method of claim 1 , further comprising:
etching the portion of the first dielectric layer and the second dielectric layer over the semiconductor device in the first portion of the active semiconductor layer to form an opening over the semiconductor device in the first portion of the active semiconductor layer.
3. The method of claim 2 , wherein the first metal layer is a contact layer.
4. The method of claim 2 , wherein the first metal layer is a via layer.
5. The method of claim 2 , wherein the first metal layer is an interconnect layer.
6. The method of claim 2 , further comprising placing one of an optic fiber, or a heterogeneous electromagnetic source, or a heterogeneous electromagnetic load in proximity of the opening.