Vacuum fixture

{
  "publication_number": "US10707652B1",
  "country": "US",
  "kind": "B1",
  "title": "Vacuum fixture",
  "abstract": "An example method includes stacking a plurality of laser diode bars proximate an alignment plate. Each respective laser diode bar has a front edge through which the respective laser diode bar emits light. The alignment plate has a first side that provides a common plane for aligning the front edges of the laser diode bars and a second side opposite the first side. The alignment plate has a plurality of microholes extending between the first and second sides. The method also includes applying suction to the plurality of laser diode bars through the plurality of microholes. The suction draws the front edges of the laser diode bars against the first side of the alignment plate such that the front edges of the laser diode bars are aligned in the common plane. Conductive plates used to clamp the plurality of laser diodes therebetween may be aligned in a similar fashion.",
  "claims": [
    "1. A system comprising: an alignment plate comprising: a first side that provides a common plane for aligning a respective front edge of each of a plurality of stacked semiconductor dies, wherein each respective semiconductor die in the plurality of stacked semiconductor dies has an upper surface and a lower surface that are perpendicular to the respective front edge; a second side opposite the first side; and a plurality of microholes extending between the first and second sides; and a suction fixture comprising: a connector configured to connect to a source of suction; and a cavity defined within the suction fixture and in fluid communication with the connector; wherein the suction fixture is configured to interface with the alignment plate to position the cavity proximate (i) the second side of the alignment plate and (ii) the plurality of microholes to apply suction to the plurality of stacked semiconductor dies through the plurality of microholes.",
    "2. The system of claim 1, wherein the plurality of microholes comprise a set of parallel linear arrays of microholes, wherein each linear array of microholes is at an angle with respect to the upper and lower surfaces of the semiconductor dies.",
    "3. The system of claim 1, wherein the plurality of stacked semiconductor dies is a plurality of laser diode bars, and wherein each respective laser diode bar in the plurality of laser diode bars is configured to emit light through the respective front edge.",
    "4. The system of claim 1, wherein the alignment plate comprises a planar PCB substrate configured to matingly engage with the suction fixture to create a seal between (i) the second side of the PCB and (ii) the cavity to direct the suction through the plurality of microholes.",
    "5. The system of claim 3, wherein at least the first side of the planar PCB substrate is coated in a metal layer that defines the common plane.",
    "6. The system of claim 1, wherein the cavity is a first cavity, wherein the connector is a first connector, wherein the alignment plate further comprises a plurality of macroholes positioned below the plurality of microholes, and wherein the suction fixture further comprises: a second connector configured to connect to the source of suction; and a second cavity defined within the suction fixture and in fluid communication with the second connector, wherein the suction fixture is further configured to interface with the alignment plate to position the second cavity proximate the plurality of macroholes to apply suction through the first plurality of macroholes to a substrate on top of which the semiconductor dies are to be stacked.",
    "7. The system of claim 6, wherein an opening size of the microholes is between 100 microns and 250 microns and wherein an opening size of the macroholes is between 500 microns and 2000 microns."
  ],
  "description_excerpt": "A laser diode is an electrically pumped semiconductor laser in which the active laser medium is formed by a PN or PIN junction of a semiconductor diode. Several laser diodes may be included on a single semiconductor substrate to form a laser diode bar. The laser diodes may be oriented in the same direction on the substrate to form an edge or facet from which light is emitted. The laser diode bars can be stacked between two conductive substrates, with the emitting edges oriented in the same direction, to form a two-dimensionally emitting surface. The laser diode bar stack may be used for pumping solid state lasers.\n\nIn an example embodiment, a vacuum fixture may be used to align respective light-emitting edges or faces of a plurality of stacked laser diode bars in a common plane. The common plane may be provided by an alignment plate that includes therein a plurality of microholes arranged in a pattern, such as a pattern of linear arrays or a random pattern. As the laser diode bars are stacked proximate the alignment plate, suction may be provided through the microholes to pull the laser diode bars against the alignment plate, thereby aligning their respective light-emitting edges in the common plane. The microholes may be arranged in the pattern (e.g., linear arrays) to ensure that each laser diode bar receives suction through at least one microhole in at least two linear arrays. The aligned laser diode bars may then be clamped together to maintain the alignment.\n\nIn a first embodiment, a method is provided that includes stacking a plurality of laser diode bars proximate an alignment plate.",
  "cpc": [
    "H01S 5/405",
    "H01L 21/68",
    "H01L 21/6838",
    "H01S 5/02365",
    "H10P 72/50",
    "H10P 72/78"
  ],
  "ipc": [
    "H01S 5/40",
    "H10P 72/50"
  ],
  "assignees": [
    "Waymo LLC"
  ],
  "inventors": [
    "Augusto Tazzoli",
    "Pierre-Yves Droz",
    "Nathaniel Golshan"
  ],
  "filing_date": "2018-11-29",
  "publication_date": "2020-07-07",
  "grant_date": "2020-07-07",
  "priority_date": "2017-08-09",
  "application_number": "US-201816204406-A",
  "family_id": "64739855",
  "cited_by_count": 4,
  "citations": [
    "US3949295A",
    "US4361091A",
    "US5394426A",
    "US5498973A",
    "US5835515A",
    "US6352873B1",
    "US6045321A",
    "WO2001045178A1",
    "US20030012638A1",
    "US20030031227A1",
    "US20030185963A1",
    "US6927086B2",
    "US20040061346A1",
    "US20050101039A1",
    "US7268005B2",
    "US20090016398A1",
    "US20100325884A1",
    "US20120168089A1",
    "US20110198817A1",
    "US20120285493A1",
    "US20130122610A1",
    "US8518814B2",
    "US20140130691A1",
    "US10170893B1"
  ]
}