Low-profile MEMS thermal printhead die having backside electrical connections
First Claim
1. A method of manufacturing a MEMS thermal printhead die on an SOI structure having a top surface, a buried oxide layer, and a mounting surface opposite the top surface, the method comprising steps for:
- (a) forming a plurality of ink-delivery sites on the top surface, wherein each ink-delivery site comprises a plurality of ink-dispensing pores formed through the SOI structure;
(b) forming an ohmic heater adjacent to at least one of the ink-dispensing pores;
(c) forming at least one under-bump metallization (“
UBM”
) pad on the mounting surface; and
(d) forming at least one through-silicon via (“
TSV”
) plug, the TSV plug electrically coupling the ohmic heater to the UBM pad through the thickness of the printhead die.
6 Assignments
0 Petitions
Accused Products
Abstract
A thermal printhead die is formed from an SOI structure as a MEMS device. The die has a printing surface, a buried oxide layer, and a mounting surface opposite the printing surface. A plurality of ink delivery sites are formed on the printing surface, each site having an ink-receiving and ink-dispensing structure. An ohmic heater is formed adjacent to each structure, and an under-bump metallization (UBM) pad is formed on the mounting surface and is electrically connected to the ohmic heater, so that ink received by the ink-delivery site and electrically heated by the ohmic heater may be delivered to a substrate by sublimation. A through-silicon-via (TSV) plug may be formed through the thickness of the die and electrically coupled through the buried oxide layer from the ohmic heater to the UBM pad. Layers of interconnect metal may connect the ohmic heater to the UBM pad and to the TSV plug.
136 Citations
18 Claims
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1. A method of manufacturing a MEMS thermal printhead die on an SOI structure having a top surface, a buried oxide layer, and a mounting surface opposite the top surface, the method comprising steps for:
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(a) forming a plurality of ink-delivery sites on the top surface, wherein each ink-delivery site comprises a plurality of ink-dispensing pores formed through the SOI structure; (b) forming an ohmic heater adjacent to at least one of the ink-dispensing pores; (c) forming at least one under-bump metallization (“
UBM”
) pad on the mounting surface; and(d) forming at least one through-silicon via (“
TSV”
) plug, the TSV plug electrically coupling the ohmic heater to the UBM pad through the thickness of the printhead die. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for manufacturing a printing system utilizing a MEMS thermal printhead die, comprising:
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(a) forming a plurality of ink-delivery sites on a top surface of an SOI structure, wherein each ink-delivery site comprises a plurality of ink-dispensing pores through the SOI structure, (b) forming a plurality of ohmic heaters, each ohmic heater adjacent to a corresponding plurality of ink-dispensing pores; (c) forming one or more under-bump metallization (“
UBM”
) pads on a mounting surface of the SOI structure;(d) forming a plurality of through-silicon via (“
TSV”
) plugs through the SOI structure, each TSV plug electrically coupling one of the ohmic heaters to the one or more UBM pads;(e) dispensing a solder ball onto each of the UBM pads; (f) reflowing the solder balls; (g) contacting the reflowed solder balls to a corresponding complementary pad on a mounting substrate; and (h) curing the solder balls so that the cured solder provides mechanical connection between the printhead die and the mounting substrate, and electrical connection from each said complementary pad to one of the ohmic heaters through the mounting surface of the SOI structure. - View Dependent Claims (10, 11, 12, 13)
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14. A method for attaching a MEMS printhead die to a mounting substrate, comprising:
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forming a plurality of under-bump metallization (UBM) pads on a mounting surface of the printhead die; forming a plurality of complementary pads on the mounting substrate; locating a solder ball onto each of the UBM pads; reflowing the solder balls on the UBM pads to form solder bumps of substantially uniform size; mechanically aligning the UBM pads of the printhead die to the complementary pads of the mounting substrate; preloading the solder bumps between the UBM pads and the complementary pads; and reflowing the solder bumps so that the solder bumps, when cured, mechanically connect the printhead die to the mounting substrate and electrically connect each of the UBM pads to its said complementary pad. - View Dependent Claims (15, 16, 17, 18)
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Specification