Method of resin encapsulating a semiconductor device

• US 4,769,344 A
• Filed: 06/16/1987
• Issued: 09/06/1988
• Est. Priority Date: 06/04/1984
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Matsuda, Sadamu, Takahama, Takashi, Sakai, Kunito
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): Pawlikowski, Beverly Ann
• Application Number:
  US07/062,644
• Time in Patent Office: 448 Days
• Field of Search: 437/216, 437/219, 437/211, 437/220, 437/213, 357/72, 357/74
• US Class Current: 29/827
• CPC Class Codes: G11C 16/18 Circuits for erasing optically
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/10 characterised by the material or arrangement of seals between parts, e.g. between cap and base of the container or between leads and walls of the container
• 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 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 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/1815 Shape
• CPC Class Codes: H01L 2924/2075 larger or equal to 1 micron less than 10 microns
• CPC Class Codes: Y10T 29/49121 Beam lead frame or beam lead device
• CPC Class Codes: Y10T 29/53196 Means to apply magnetic force directly to position or hold work part

Abstract

A semiconductor device and a method for manufacturing a semiconductor device of a type having a resin package and a window in the package such as a quartz glass window transparent to ultraviolet rays. A semiconductor chip is bonded onto a surface of a die pad of a lead frame. A softened resin is then extruded from the opposite surface of the die pad through gaps between the die pad and the leads with the extrusion being carried out in an inert gas atmosphere. An inner package member is thus formed surrounding the semiconductor chip. An outer package member, made of a thermosetting resin having a weight ratio of resin to filler less than that of the inner package, is molded around the chip assembly and inner package.

Claims

1. A method for fabricating a semiconductor device, comprising the steps of:

(a) bonding a semiconductor chip (8) onto a surface of a die (6) of a lead frame embodying said die pad and including a plurality of electrical leads (7) having ends spaced from the die pad to define gaps therebetween;

(b) turning the lead frame upside down;

(c) disposing a layer of softened resin (10a) against another, opposite surface of said die pad and vertically overlying said lead ends and gaps in an inert gas atmosphere;

(d) exerting a downwardly directed force on an upper surface of the softened resin such that, as assisted by gravity, a portion of the resin is extruded downwardly between the gaps to form an inner package (10) surrounding said semiconductor chip and defining a space (11) therearound filled with said inert gas; and

(e) hardening the extruded resin.

2. The method claimed in claim 1, wherein said exerting step comprises disposing a flat plate (15) against an upper surface of the resin layer, and applying a downwardly directed force to the plate.

3. The method claimed in claim 2, wherein the plate is made of a magnetic material, and the force is applied by disposing magnet means (20) such that a magnetic field generated thereby urges the plate downwardly.

4. The method claimed in claim 2, wherein the force is applied by mechanically pushing the plate downwardly.

5. The method claimed in claim 1, wherein said resin is a thermosetting resin.

6. The method claimed in claim 5, further comprising the step of molding an outer package (14) around the extruded resin of said resin layer, said outer package being made of a thermosetting resin, the thermosetting resins of said inner and outer packages containing an inorganic filler with a weight ratio of resin to filler being smaller in said inner package than in said outer package.

7. The method claimed in claim 6, wherein a weight ratio of resin to filler of said inner package is approximately 150:

400, and a weight ratio of resin to filler of said outer package is approximately 150;

300.

8. The method claimed in claim 1, wherein said softened resin is extruded onto a surface of a cover member (12) covered by a flexible film (13), said space being defined between an inner surface of said cover member and said semiconductor chip.