Linear integrated optocoupler and method for forming the same

• US 6,031,251 A
• Filed: 11/28/1994
• Issued: 02/29/2000
• Est. Priority Date: 06/07/1993
• Status: Expired due to Fees

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Gempe, Horst A., Hoshizaki, Gary W.
• Primary Examiner(s): Jackson, Jr., Jerome
• Application Number:
  US08/345,917
• Time in Patent Office: 1,919 Days
• Field of Search: 257/84, 257/85, 257/80, 257/98
• US Class Current: 257/84
• 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 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 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 2924/181 Encapsulation
• CPC Class Codes: H01L 31/167 the light sources and the devices sensitive to radiation all being semiconductor devices characterised by potential barriers
• CPC Class Codes: H01L 31/173 formed in, or on, a common substrate

Abstract

A linear optocoupler (71) having a light emitting diode (28) and a detector diode (29) formed on a common semiconductor substrate (33). Light emitted by the light emitting diode (28) is transmissive to semiconductor substrate (33). A layer of light reflective material (34) is formed on a side opposite from which the light emitting diode (28) and the detector diode (29) on the semiconductor substrate (33). A portion of light emitted by the light emitting diode (28) transmits through the semiconductor substrate (33) to be reflected by the layer of light reflective material (34). The reflected light transmits through the semiconductor substrate (33) to be received by the detector diode (29). A photo detector diode (61) and the semiconductor substrate (33) including the light emitting diode (28) and the detector diode (29) are mounted on a lead frame (51) co-planar to one another. A light flux coupling media (76) couples light from the light emitting diode (28) to the photo detector diode (29).

Claims

1. A linear integrated optocoupler comprising:

an integrated light emitting diode and detector diode wherein said detector diode detects light emitted by said light emitting diode and provides a signal for linearizing a response of said light emitting diode, said integrated light emitting diode and detector diode comprising;

a semiconductor substrate;

a first epitaxial layer formed on a first side of said semiconductor substrate;

a second epitaxial layer formed on a second side of said semiconductor substrate, said first and second sides of said semiconductor substrate oppose one another, said first epitaxial layer is an anode of said light emitting diode, said second epitaxial layer is an anode of said detector diode, and said semiconductor substrate is a common cathode of said integrated light emitting diode and detector diode;

a photodetector diode for receiving light emitted by said light emitting diode;

a lead frame including a first area and a second area, said first and second areas being coplanar, said integrated light emitting diode and detector diode being conductively mounted to said first area of said lead frame and said photodetector diode being conductively mounted to said second area, said photodetector diode is electrically and physically isolated from said integrated light emitting diode and detector diode,

a light flux coupling material placed on and between said first and second areas of said lead frame for coupling light emitted by said light emitting diode to said photodetector diode wherein said light flux coupling material covers said integrated light emitting diode and detector diode on said first area and said photodetector diode on said second area; and

a protective enclosure formed around said first and second areas and said light flux coupling material for enclosing said light emitting diode and detector diode, and said photodetector diode.

2. The linear optocoupler as recited in claim 1 wherein said light flux coupling material is a silicone gel.

3. The linear optocoupler as recited in claim 1 wherein said protective enclosure is plastic.