Semiconductor package with adhesive material pre-printed on the lead frame and chip, and its manufacturing method

• US 20110070698A1
• Filed: 04/30/2010
• Published: 03/24/2011
• Est. Priority Date: 09/21/2009
• Status: Active Grant

• Current Assignee: Alpha & Omega Semiconductor, Ltd.
• Original Assignee: Alpha & Omega Semiconductor, Ltd.
• Inventors: Zhang, Xiaotian, Lu, Jun
• Granted Patent: US 8,222,088 B2
• Time in Patent Office: Days
• US Class Current: 438/113
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05 of an individual bonding area
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/371 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/40245 the item being metallic
• CPC Class Codes: H01L 2224/4103 Connectors having different sizes
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48599 Principal constituent of the connecting portion of the wire connector being Gold (Au)
• CPC Class Codes: H01L 2224/48699 Principal constituent of the connecting portion of the wire connector being Aluminium (Al)
• CPC Class Codes: H01L 2224/48799 Principal constituent of the connecting portion of the wire connector being Copper (Cu)
• CPC Class Codes: H01L 2224/49111 the connectors connecting two common bonding areas, e.g. Litz or braid wires
• CPC Class Codes: H01L 2224/73221 Strap and wire connectors
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 2224/83192 : wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83855 : Hardening the adhesive by curing, i.e. thermosetting
• CPC Class Codes: H01L 2224/83856 : Pre-cured adhesive, i.e. B-stage adhesive
• CPC Class Codes: H01L 2224/84 : using a strap connector
• CPC Class Codes: H01L 2224/8585 : using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 2224/92 : Specific sequence of method steps
• CPC Class Codes: H01L 2224/92247 : the second connecting process involving a wire connector
• CPC Class Codes: H01L 23/3107 : the device being completely enclosed
• CPC Class Codes: H01L 23/49513 : having bonding material between chip and die pad
• CPC Class Codes: H01L 23/4952 : the additional leads being a bump or a wire
• CPC Class Codes: H01L 23/49562 : for devices being provided for in H01L29/00
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/06 : of a plurality of bonding areas
• CPC Class Codes: H01L 24/27 : Manufacturing methods
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/37 : of an individual strap connector
• CPC Class Codes: H01L 24/40 : of an individual strap connector
• CPC Class Codes: H01L 24/41 : of a plurality of strap connectors
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• 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 24/83 : using a layer connector
• CPC Class Codes: H01L 24/84 : using a strap connector
• 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 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/0781 : being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/1306 : Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/13091 : Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

This invention discloses a semiconductor package with adhesive material pre-printed on the lead frame and chip, and the manufacturing method. The adhesive material is applied onto the chip carrier and the pin of the lead frame and also on the front electrode of the semiconductor chip via pre-printing. The back of the semiconductor chip is adhered on the chip carrier, and the front electrode of the semiconductor chip and the pin are connected respectively with a metal connector. The size, shape and thickness of the adhesive material are applied according to different application requirements according to size and shapes of the contact zone of the semiconductor chip and the metal connector. Particularly, the adhesive zones are formed by pre-printing the adhesive material thus significantly enhance the quality and performance of semiconductor products, and improves the productivity.

Claims

1. A method for manufacturing a semiconductor package comprising:

printing a first adhesive material onto a plurality of front electrodes of a semiconductor chip disposed on a wafer at room temperature, followed by pre-curing the adhesive material at a first temperature then dicing the wafer into a plurality of semiconductor chips;

applying a second high temperature for connecting the plurality of front electrodes of a semiconductor chip onto a plurality of metal connection plates by flipping the semiconductor chip and adhering the pre-cured first adhesive material on each front electrode to one of the plurality of the metal connecting plates;

printing a second adhesive material on a plurality of adhesive zones on a chip carrier of a lead frame at room temperature followed by curing the adhesive material at a third high temperature;

applying a fourth high temperature for connecting the chip carrier to a bottom of the semiconductor chip by adhering the pre-cured second adhesive material to the bottom of the semiconductor chip; and

applying a molding material to encapsulate the semiconductor chip and at least portions of the lead frame and the metal connections plates.

2. The method for manufacturing a semiconductor package of claim 1 wherein:

the steps of applying the first high temperature and the third high temperature comprise steps of applying the first and third high temperatures substantially within a range of 110°

C. to 140°

C. for curing the first and second adhesive materials into their B stages respectively.

3. The method for manufacturing a semiconductor package of claim 1 wherein:

the step of printing a first adhesive material onto a plurality of front electrodes of a semiconductor chip on a wafer level further comprising a step of;

providing a stencil or screen having a number of openings corresponding to a number of zones on the front electrodes to be printed with the first adhesive material on the wafer;

printing the first adhesive material onto the front electrodes through the stencil or screen, whereas, the first adhesive material printed having a thickness substantially the same as a thickness of the stencil or screen.

4. The method for manufacturing a semiconductor package of claim 1 wherein:

the steps of applying the second and fourth high temperatures comprise steps of applying the second and fourth temperatures substantially in a range of 95°

C. to 130°

C.

5. The method for manufacturing a semiconductor package of claim 1 wherein:

the step of applying the fifth high temperatures further comprises a step of applying the fifth temperature at substantially 175°

C.

6. The method for manufacturing a semiconductor package of claim 1 wherein:

the step of forming the plurality of metal connection plates is a step of forming a top lead frame as the plurality of metal connection plates.

7. The method for manufacturing a semiconductor package of claim 1 wherein:

the step of forming the plurality of metal connection plates is a step of forming an array of top lead frames as the plurality of metal connection plates.

8. The method for manufacturing a semiconductor package of claim 1 wherein:

the step of forming the plurality of metal connection plates is a step of forming an end of each of the plurality of metal connection plates extending outside the molding material functioning as pins of the package.