Process control monitors for interferometric modulators
AssigneeIdc, LLC
InventorsWilliam Cummings, Brian Gally
Life of this patent
Estimating the term…
Abstract
Process control monitors are disclosed that are produced using at least some of the same process steps used to manufacture a MEMS device. Analysis of the process control monitors can provide information regarding properties of the MEMS device and components or sub-components in the device. This information can be used to identify errors in processing or to optimize the MEMS device. In some embodiments, analysis of the process control monitors may utilize optical measurements.
Claims34
A method of monitoring the extent of etching of a first material positioned between and adjacent to two layers of other material during manufacturing of a micro-electro-mechanical system (MEMS), comprising:
- manufacturing a process control monitor that comprises the two layers of other material and the first material disposed between and adjacent to the two layers, wherein one of the two layers comprises a hole;
- exposing the hole to an etchant;
- and
- optically detecting a distance from the center of the hole to where the etchant has etched away the first material, whereby the distance is indicative of the extent of etching of the first material.
A wafer, comprising:
- a plurality of structures comprising a sacrificial layer and at least one layer above and adjacent to the sacrificial layer, wherein the structures become interferometric modulators upon removal of the sacrificial layer, wherein the at least one layer above and adjacent to the sacrificial layer comprises a plurality of holes through which an etchant can reach the sacrificial layer;
- and
- a process control monitor also comprising the sacrificial layer and the at least one layer above and adjacent to the sacrificial layer, wherein the at least one layer above and adjacent to the sacrificial layer in the process control monitor comprises multiple holes, wherein the distance between the holes in the process control monitor is greater than the distance between the plurality of holes in said plurality of structures.
A wafer, comprising:
- a plurality of structures comprising a sacrificial layer and at least one layer above and adjacent to the sacrificial layer, wherein the structures become interferometric modulators upon removal of the sacrificial layer, wherein the at least one layer above and adjacent to the sacrificial layer comprises a plurality of holes through which an etchant can reach the sacrificial layer;
- and
- a process control monitor also comprising the sacrificial layer and the at least one layer above and adjacent to the sacrificial layer, wherein the at least one layer above and adjacent to the sacrificial layer in the process control monitor comprises a single hole.
A method of manufacturing a wafer having a micro-electro-mechanical system (MEMS) and a process control monitor structure, the method comprising:
- forming a plurality of structures, wherein forming the plurality of structures includes one or more material deposition and removal steps, wherein the structures comprise a sacrificial layer and at least one layer above and adjacent to the sacrificial layer, wherein the at least one layer above and adjacent to the sacrificial layer comprises a plurality of holes through which an etchant can reach the sacrificial layer;
- simultaneously forming a process control monitor, wherein forming the process control monitor includes said one or more material deposition and removal steps, wherein the process control monitor also comprises the sacrificial layer and the at least one layer above and adjacent to the sacrificial layer, wherein the at least one layer above and adjacent to the sacrificial layer in the process control monitor comprises multiple holes, wherein the distance between the holes in the process control monitor is greater than the distance between the plurality of holes in said plurality of structures;
- and
- exposing the plurality of structures and the process control monitor to an etchant.
A wafer, comprising:
- a micro-electro-mechanical structure (MEMS);
- and
- means for measuring extent of etching of a material removed during manufacturing of the MEMS.
A process control monitor produced by process comprising:
- depositing at least three layers of material on top of each other;
- and
- forming a hole in the top layer of material.
Dependencies are inferred from the claim text.