Composite light-emitting device, semicon ductor light-emitting unit and method for fabricating the unit

• US 20020028527A1
• Filed: 09/07/2001
• Published: 03/07/2002
• Est. Priority Date: 01/11/1999
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Obara, Kunihiko, Inoue, Tomio, Maeda, Toshihide
• Granted Patent: US 6,468,821 B2
• Time in Patent Office: Days
• US Class Current: 438/29
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/94 at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/01039 Yttrium [Y]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/12032 : Schottky diode
• CPC Class Codes: H01L 2924/12033 : Gunn diode
• CPC Class Codes: H01L 2924/12035 : Zener diode
• CPC Class Codes: H01L 2924/12036 : PN diode
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/1306 : Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2933/0016 : relating to electrodes
• CPC Class Codes: H01L 2933/0041 : relating to wavelength conversion elements
• CPC Class Codes: H01L 33/32 : containing nitrogen
• CPC Class Codes: H01L 33/38 : with a particular shape
• CPC Class Codes: H01L 33/44 : characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/505 : characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/54 : having a particular shape
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01S 5/32341 : blue laser based on GaN or GaP

Abstract

A composite light-emitting device according to the present invention includes a light-emitting element including a transparent substrate and a multilayer structure formed on the substrate. The multilayer structure includes first and second semiconductor layers of first and second conductivity types, respectively. The device further includes a submount member for mounting the light-emitting element thereon. The principal surface of the submount member faces the multilayer structure. The submount member is electrically connected to the light-emitting element. The light-emitting element is covered with a wavelength-shifting resin member. The resin member is provided on the principal surface of the submount member and contains a photofluorescent or filtering compound. The photofluorescent compound shifts the wavelength of radiation that has been emitted from the light-emitting element, while the filtering compound partially absorbs the radiation.

Claims

1. A method for fabricating a semiconductor light-emitting unit, comprising the steps of:

making a light-emitting element by forming a multilayer structure on a transparent substrate and forming electrodes on the multilayer structure, the multilayer structure including first and second semiconductor layers of first and second conductivity types, respectively;

making a submount member including counter electrodes on the principal surface thereof, the counter electrodes facing the electrodes of the light-emitting element;

forming microbumps on the electrodes or on the counter electrodes;

mounting the light-emitting element facedown on the principal surface of the submount member such that the multi-layer structure faces the principal surface and that the electrodes of the light-emitting element are electrically connected to the counter electrodes via the microbumps; and

coating the light-emitting element with a wavelength-shifting resin medium that will be supported on the principal surface of the submount member when cured, the wavelength-shifting resin medium containing a photofluorescent or filtering compound, the photofluorescent compound shifting the wave-length of radiation that has been emitted from the light-emitting element, the filtering compound partially absorbing the radiation.

2. A method for fabricating a semiconductor light-emitting unit, comprising the steps of:

a) making multiple light-emitting elements by forming a multilayer structure on each of a plurality of transparent substrates and forming electrodes on the multilayer structure, the multilayer structure including first and second semiconductor layers of first and second conductivity types, respectively;

b) making multiple submount members on a wafer, each said submount member including;

a bonding pad on the principal surface thereof;

counter electrodes that face the electrodes of associated one of the light-emitting elements; and

a backside electrode on another surface thereof opposite to the principal surface;

c) forming microbumps on the electrodes or on the counter electrodes by a stud bump forming or plating technique;

d) bringing the electrodes of each said light-emitting element into contact with the counter electrodes of associated one of the submount members via the microbumps and fusing the microbumps by applying ultrasonic waves or heat thereto such that the microbumps and the associated electrodes are bonded together, thereby electrically connecting the light-emitting elements to the associated submount members and bonding the light-emitting elements onto the respective principal surfaces of the submount members;

e) coating each said light-emitting element with a wave-length-shifting resin medium that will be supported on the principal surface of the associated submount member and then curing the wavelength-shifting resin medium, thereby obtaining a plurality of composite light-emitting devices, each including one of the light-emitting elements and associated one of the submount members, the wavelength-shifting resin medium containing a photofluorescent or filtering compound, the photofluorescent compound shifting the wavelength of radiation that has been emitted from the light-emitting element, the filtering compound partially absorbing the radiation;

f) dicing the wafer, on which the composite light-emitting devices have been formed, into multiple chips;

g) securing each said composite light-emitting device, which is included on one of the chips, onto a mount of a lead-frame or a wiring board such that the backside electrode of the submount member thereof is bonded to the mount via a conductive paste; and

h) connecting the bonding pad of each said submount member to the associated leadframe or wiring board with a wire.

3. The method of claim 2, further comprising, between the steps d) and e), the step of polishing a light-emitting surface of the substrate for each said light-emitting element on the opposite side to another surface thereof on which the multilayer structure is formed such that the light-emitting surface becomes substantially parallel to a surface of the associated submount member on which the backside electrode is formed.

4. The method of claim 2, further comprising, between the steps e) and f), the step of polishing an outer surface of part of the wavelength-shifting resin medium above each said light-emitting element such that the outer surface becomes substantially parallel to the surface of the associated submount member on which the backside electrode is formed