Process control monitors for interferometric modulators
AssigneeIdc, LLC
InventorsWilliam Cummings, Brian Gally
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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.
Claims29
A method for determining the effect of an interferometric modulator manufacturing process on color reflected from interferometric modulators manufactured by the process, comprising:
- manufacturing a plurality of interferometric modulators comprising posts that support a first mechanical membrane;
- manufacturing a process control monitor etalon comprising posts that support a second mechanical membrane, wherein the posts in the process control monitor are present in higher density than the posts in the plurality of interferometric modulators;
- and
- detecting light reflected from the process control monitor etalon, whereby the detected light provides an indication of the depth of an interferometric cavity in the plurality of interferometric modulators.
A process control monitor for monitoring the effect of a process for manufacturing interferometric modulators on the color of light reflected by those interferometric modulators, comprising a test etalon that comprises a higher density of posts supporting a mechanical membrane in the test etalon than in interferometric modulators produced by the process.
A wafer, comprising:
- a plurality of reflective display elements adapted for use in a display;
- and
- a process control monitor that comprises an etalon having a higher density of posts supporting a mechanical membrane than in the plurality of reflective display elements.
A process control monitor, comprising an etalon having a conductive partial mirror and a conductive mechanical membrane comprising a mirror, wherein the mechanical membrane is separated from the partial mirror by a plurality of posts, wherein the density of posts is high enough such that the mechanical membrane cannot collapse toward the partial mirror when a voltage is applied between the partial mirror and the mechanical membrane.
A method of manufacturing a combined micro-electro-mechanical system (MEMS) and process control monitor structure, comprising:
- forming a MEMS structure, wherein forming the MEMS structure includes one or more material deposition and patterning steps, wherein the MEMS structure comprises a first mechanical membrane supported by a first plurality of posts;
- and
- simultaneously forming a process control monitor, wherein forming the process control monitor includes said one or more material deposition and patterning steps, the process control monitor comprising a second mechanical membrane supported by a second plurality of posts, wherein the second plurality of posts are present in a higher density than the first plurality of posts.
A wafer, comprising:
- a plurality of first means for reflecting light for use in a display;
- and
- second means for stably reflecting light having substantially the same color as reflected from at least one of said second means.
A process control monitor produced by a process comprising:
- forming a partial mirror;
- forming a mechanical membrane;
- and
- forming a plurality of posts supporting the mechanical membrane and separating the mechanical membrane from the partial mirror, wherein the density of posts is high enough such that the mechanical membrane cannot collapse toward the partial mirror when a voltage is applied between the partial mirror and the mechanical membrane.
Dependencies are inferred from the claim text.