Methods for depositing, releasing and packaging micro-electromechanical devices on wafer substrates
First Claim
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1. A method for forming a MEMS device, comprising:
- providing a first semiconductor wafer having electrodes thereon;
providing a second transparent wafer;
providing a sacrificial layer on the second wafer;
forming a plurality of MEMS elements on the sacrificial layer wherein MEMS are deflectable elements;
releasing the plurality of MEMS devices by etching away the sacrificial layer;
mixing one or more spacer elements into an adhesive or providing one or more spacer elements separately from the adhesive for separating the wafers during and after aligning the first and second wafers and bonding;
applying the adhesive to one or both of the first and second wafers;
bonding the first and second wafers together with the spacer elements therebetween so that the first and second wafers are held together in a spaced apart relationship as a wafer assembly;
wherein the aligning comprises aligning each deflectable element on the second wafer with at least one electrode on the first wafer singulating the wafer assembly into individual dies; and
wherein a plurality of light blocking masks are formed on the second wafer;
wherein when the wafer assembly is singulated into wafer assembly dies, a light blocking mask is disposed on a second wafer portion within each wafer assembly die.
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Abstract
A method for forming a MEMS device is disclosed, where a final release step is performed just prior to a wafer bonding step to protect the MEMS device from contamination, physical contact, or other deleterious external events. Without additional changes to the MEMS structure between release and wafer bonding and singulation, except for an optional stiction treatment, the MEMS device is best protected and overall process flow is improved. The method is applicable to the production of any MEMS device and is particularly beneficial in the making of fragile micromirrors.
51 Citations
56 Claims
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1. A method for forming a MEMS device, comprising:
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providing a first semiconductor wafer having electrodes thereon;
providing a second transparent wafer;
providing a sacrificial layer on the second wafer;
forming a plurality of MEMS elements on the sacrificial layer wherein MEMS are deflectable elements;
releasing the plurality of MEMS devices by etching away the sacrificial layer;
mixing one or more spacer elements into an adhesive or providing one or more spacer elements separately from the adhesive for separating the wafers during and after aligning the first and second wafers and bonding;
applying the adhesive to one or both of the first and second wafers;
bonding the first and second wafers together with the spacer elements therebetween so that the first and second wafers are held together in a spaced apart relationship as a wafer assembly;
wherein the aligning comprises aligning each deflectable element on the second wafer with at least one electrode on the first wafersingulating the wafer assembly into individual dies; and
wherein a plurality of light blocking masks are formed on the second wafer;
wherein when the wafer assembly is singulated into wafer assembly dies, a light blocking mask is disposed on a second wafer portion within each wafer assembly die. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method for making a micromirror array device, comprising:
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providing a first semiconductor wafer;
providing a second transparent wafer;
forming circuitry and a plurality of electrodes on or in the first wafer;
forming a plurality of deflectable elements on second wafer;
applying an adhesion reducing agent and/or a getter to one or both of the wafers;
aligning the first and second wafers;
bonding the first and second wafers together to form a wafer assembly, wherein a plurality of light blocking masks are formed on the second wafer;
wherein when the wafer assembly is singulated into wafer assembly dies, a light blocking mask is disposed on a second wafer portion within each wafer assembly die;
separating the wafer assembly into individual wafer assembly dies. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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Specification