Manufacturing method for micro-SD flash memory card

• US 8,141,240 B2
• Filed: 12/28/2007
• Issued: 03/27/2012
• Est. Priority Date: 08/04/1999
• Status: Expired due to Fees

• Current Assignee: Super Talent Technology, Corporation
• Original Assignee: Super Talent Electronics, Inc.
• Inventors: Nan, Nan, Hsueh, Paul, Ma, Abraham C., Shen, Ming-Shiang, Hiew, Siew S.
• Primary Examiner(s): Banks, Derris
• Assistant Examiner(s): Kue, Kaying
• Application Number:
  US11/966,871
• Publication Number:
  US 20080145968A1
• Time in Patent Office: 1,551 Days
• Field of Search: 298/32, 298/34, 298/40, 298/41, 298/46, 294/12
• US Class Current: 29/836
• CPC Class Codes: H01L 21/561 Batch processing
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/85 using a wire connector
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 23/5388 for flat cards, e.g. credit cards cards per se G06K19/00
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01047 Silver [Ag]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H05K 1/117 : Pads along the edge of rigid circuit boards, e.g. for pluggable connectors
• CPC Class Codes: H05K 2201/09063 : Holes or slots in insulating substrate not used for electrical connections
• CPC Class Codes: H05K 2201/0909 : Preformed cutting or breaking line
• CPC Class Codes: H05K 3/0052 : Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• CPC Class Codes: H05K 3/284 : for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: Y10T 29/49002 : Electrical device making
• CPC Class Codes: Y10T 29/49124 : On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49133 : with component orienting
• CPC Class Codes: Y10T 29/49137 : Different components
• CPC Class Codes: Y10T 29/49146 : with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49789 : Obtaining plural product pieces from unitary workpiece

Abstract

A method for fabricating MicroSD devices includes forming a PCB panel having multiple PCBs arranged in parallel rows, with each PCB connected to its neighboring PCBs in each row by relatively narrow connecting bridge pieces, and separated from PCBs of adjacent rows by elongated stamped out blank slots. Passive components are attached by conventional surface mount technology (SMT) techniques. IC chips, including a MicroSD controller chip and a flash memory chip, are attached to the PCB by wire bonding or other chip-on-board (COB) technique. A molded housing is then formed over the IC chips and passive components using a mold that prevents formation of plastic on the upper surface of each PCB. The connecting bridge pieces are then cut using using a rotary saw. A front edge chamfer process is then performed.

Claims

1. A method for producing a plurality of MicroSD devices, the method comprising:

producing a printed circuit board (PCB) panel including a plurality of PCBs arranged in a plurality of rows, wherein all of said PCBs have a first width, and wherein at least one said PCB in each row is connected to a first adjacent PCB by a first connecting bridge structure and to a second adjacent PCB by a second connecting bridge structure, wherein the first and second connecting bridge structures have a second width that is narrower than the first width, and wherein the PCB panel defines a plurality of elongated stamped blank slots defined on the sides of each row such that side edges of each said PCB are exposed,

attaching at least one passive component and at least one integrated circuit to each said PCB;

forming a single-piece molded housing on a second surface of the PCB such that said at least one passive component and said at least one IC die are covered by said molded housing, and portions of said molded housing cover said side edges of each said PCB, wherein said first connecting bridge structure and said second connecting bridge structure extend from opposite ends of the molded housing formed on said at least one said PCB in each row;

wherein forming said single-piece molded housing comprises disposing said PCB panel into a first molding die including a plurality of raised island structures, each raised island structure being received inside a corresponding one of said elongated stamped blank slots such that a predetermined gap is defined between each side edge of each said PCB and a corresponding facing wall of an adjacent raised island structure; and

singulating said PCB panel after forming said single-piece molded housings by cutting said first and second bridge structures using a rotating blade, thereby providing said plurality of MicroSD devices.

2. The method according to claim 1, wherein producing said PCB panel comprises stamping predetermined regions of a PCB sheet to form said plurality of elongated stamped blank slots such that a hook shape is formed on a first side edge of each said PCB and extends into a corresponding one of said elongated stamped blank slots.

3. The method according to claim 1, wherein said first molding die further comprises a plurality of alignment poles, and wherein disposing said PCB panel into said first molding die comprises operably engaging said alignment poles into corresponding alignment holes defined in said PCB panel.

4. The method according to claim 1, further comprising grinding a front edge of said each of said plurality of MicroSD devices to provide a chamfer thereon.

5. The method according to claim 1,

wherein producing said PCB panel comprises forming each said PCB to include opposing first and second surfaces, a plurality of metal contacts disposed on the first surface, a plurality of first contact pads disposed on the second surface, a plurality of second contact pads disposed on the second surface, and a plurality of conductive traces formed on the PCB such that each conductive trace is electrically connected to at least one of an associated metal contact, a first contact pad and a second contact pad;

and

wherein attaching said at least one passive component and said at least one integrated circuit to each said PCB comprises;

attaching said at least one passive component to the first contact pads using a surface mount technique, and

attaching said at least one unpackaged integrated circuit (IC) die to the second contact pads using a chip-on-board technique.

6. The method of claim 5, wherein attaching said at least one passive component comprises:

printing a solder paste on said first contact pads;

mounting said at least one component on said first contact pads; and

reflowing the solder paste such that said at least one component is fixedly soldered to said first contact pads.

7. The method of claim 6, further comprising grinding a wafer including said at least one IC die such that a thickness of said wafer is reduced during said grinding, and then dicing said wafer to provide said at least one IC die.

8. The method of claim 7, wherein attaching at least one IC die comprises bonding said at least one IC die to the second surface of the PCB and wire bonding the at least one IC die to said second contact pad.