Method of affixing a heat sink to a substrate and package thereof

{
  "publication_number": "US6677185B2",
  "country": "US",
  "kind": "B2",
  "title": "Method of affixing a heat sink to a substrate and package thereof",
  "abstract": "A method of affixing a heat sink to a substrate and package thereof having a substrate with a position for receiving a semiconductor chip, at least a semiconductor chip for affixing on the position and electrically connecting the substrate, an appropriate thickness of adhesive agent by scraping by means of screen printing technology, a heat sink for covering the semiconductor chip and provided with a plurality of dimples for affixing to the substrate, the method including steps of affixing the semiconductor to the substrate and utilizing a scraper to apply a layer of adhesive agent with an appropriate thickness of adhesive on a platform from the adhesive agent; utilizing a sucker to move the heat sink to a position above the layer of adhesive agent, and dipping the dimples of the heat sink into the adhesive layer so as to adhere some adhesive agent onto the dimples, and then moving the heat sink above the semiconductor chip; affixing the heat sink to the substrate to cover the semiconductor chip; and enclosing the heat sink with epoxy resin to form a package.",
  "claims": [
    "1. A method of affixing a heat sink to a substrate and package thereof, having a substrate with a position for receiving a semiconductor chip, at least a semiconductor chip for affixing on said position and electrically connecting said substrate, an appropriate thickness of adhesive agent by scraping by means of screen printing technology, a heat sink for covering said semiconductor chip and provided with a plurality of dimples for affixing to said substrate, said method comprising steps of: a. affixing said semiconductor to said substrate and utilizing a scraper to apply a layer of adhesive agent with an appropriate thickness of adhesive on a platform from said adhesive agent; b. utilizing a sucker to move said heat sink to a position above said layer of adhesive agent, and dipping said dimples of said heat sink into said adhesive layer so as to adhere some adhesive agent onto said dimples, and then moving said heat sink above said semiconductor chip; c. affixing said heat sink to said substrate to cover said semiconductor chip; and d. enclosing said heat sink with epoxy resin to form a package.",
    "2. A method of affixing a heat sink to a substrate and package thereof as claimed in claim 1, wherein said semiconductor is affixed to said substrate by wire bonding.",
    "3. The method of affixing a heat sink to a substrate and package thereof as claimed in claim 1, wherein connection between said semiconductor chip and said substrate is accomplished by flip chip technology.",
    "4. The method of affixing a heat sink to a substrate and package thereof as claimed in claim 1, wherein a portion of said heat sink is not be covered by said epoxy resin."
  ],
  "description_excerpt": "(a) Field of the Invention\n\nThis invention is related to a method of affixing a heat sink to a substrate and package of the heat sink and the substrate, wherein a chip is first affixed to a substrate and then covered with a heat sink for dissipating heat generated during the working of the chip.\n\n(b) Description of the Prior Art\n\nAs far as we know, semiconductor chips will generally heat up while working. Therefore, it is necessary to use a heat sink to cover the chip in order to dissipate the heat generated by the semiconductor chip.\n\nThe conventional method of affixing and adhering a heat sink to a substrate is shown in FIGS. 1, 2 A, 2 B and 2 C. As illustrated, a semiconductor chip 2 ′ is first affixed on the substrate 1 ′, and then a sprayer 4 ′ is used to apply an adhesive agent 41 ′ on the substrate 1 ′ corresponding to the four dimples 31 ′ on the bottom side of the heat sink 3 ′. Then the heat sink 3 ′ is adjusted so that the dimples 31 ′ are aligned with the adhesive agent 41 ′ and moved to connect with the substrate. Finally, epoxy resin 5 ′ is used to enclose the heat sink 3 ′ to form a package.\n\nHowever, such a method suffers from the following drawbacks: Firstly, since it is necessary to use the sprayer 4 ′ to spray an appropriate amount of adhesive agent 41 ′ to four positions corresponding to the dimples 31 ′ of the heat sink 3 ′, the physical and chemical properties of the adhesive agent 41 ′ within the sprayer 4 ′ and the decrease in the amount of the adhesive agent 41 ′ will often change its viscosity, thereby causing the output of the adhesive agent being sprayed to vary.",
  "cpc": [
    "H10W 76/60",
    "H10W 72/073",
    "H10W 72/07336",
    "H10W 72/07337",
    "H10W 72/354",
    "H10W 72/5522",
    "H10W 72/884",
    "H10W 74/00",
    "H10W 76/63",
    "H10W 90/734",
    "H10W 90/754",
    "H10W 95/00"
  ],
  "ipc": [
    "H01L 21/50",
    "H01L 21/58",
    "H01L 21/60",
    "H01L 23/02",
    "H01L 23/10",
    "H01L 23/29"
  ],
  "assignees": [
    "Orient Semiconductor Electronics Ltd"
  ],
  "inventors": [
    "Hung Chin",
    "Ching-Yi Hu"
  ],
  "filing_date": "2002-06-03",
  "publication_date": "2004-01-13",
  "grant_date": "2004-01-13",
  "priority_date": "2001-11-29",
  "application_number": "US-15903002-A",
  "family_id": "21679852",
  "cited_by_count": 13,
  "citations": [
    "US5486720A",
    "US6278182B1"
  ]
}