Method of making an optoelectronic device

• US 5,614,131 A
• Filed: 05/01/1995
• Issued: 03/25/1997
• Est. Priority Date: 05/01/1995
• Status: Expired due to Term

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Suppiah, Shanmugam, Elliott, Alexander J., Mukerji, Prosanto K.
• Primary Examiner(s): Vargot, Mathieu D.
• Application Number:
  US08/431,994
• Time in Patent Office: 694 Days
• Field of Search: 264/1.1, 264/1.7, 264/1.9, 264/1.24, 264/1.25, 264/553, 264/272.11, 264/272.14, 264/272.15, 264/272.17, 264/334, 264/101, 264/102, 264/DIG. 78 , 264/571
• US Class Current: 264/1.9
• CPC Class Codes: B29C 39/10 incorporating preformed parts or layers, e.g. casting around inserts or for coating articles coating a surface by casting in general B05D1/30, B29C39/126 takes precedence
• CPC Class Codes: B29C 70/84 by moulding material on preformed parts to be joined joining plastic parts by moulding B29C65/70
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• 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 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 2924/12041 LED
• CPC Class Codes: H01L 31/02325 the optical elements not being integrated nor being directly associated with the device
• CPC Class Codes: H01L 31/173 formed in, or on, a common substrate

Abstract

An optoelectronic device is fabricated by casting a transparent polymeric body surrounding an electronic component. A reflective layer is formed over the polymeric body. The reflective layer acts as a mirror to reflect light emitted by one electronic component to another electronic component which receives the light. By casting the polymeric body, a consistent and defined shape for optical transmission is provided for forming the shape of the reflective layer.

Claims

1. A method of forming a polymer on a substrate, comprising the steps of:

providing a substrate having a top surface and a bottom surface and having an opening;

providing at least one electronic component coupled to the top surface of the substrate;

providing a base having a cavity formed therein;

disposing a release film between the substrate and the base;

disposing the substrate over the base wherein the top surface of the substrate is adjacent the base and the at least one electronic component is disposed over the cavity;

dispensing through the opening in the substrate a polymer in the cavity of the base, wherein the polymer forms a polymeric body surrounding at least a portion of the substrate and the at least one electronic component; and

curing the polymeric body.

2. The method of claim 1 further comprising holding the release film against the cavity before the step of dispensing the polymer.

3. The method of claim 2 wherein the step of holding comprises providing a hole in the base to the cavity and pulling a vacuum through the hole.

4. The method of claim 1 wherein the step of disposing the release film further comprises disposing a release film comprised of a reflective layer.

5. The method of claim 4 further comprising the step of forming an opaque polymeric body surrounding the reflective layer.

6. The method of claim 1 further comprising the step of forming an opaque polymeric body surrounding the polymeric body.

7. A method of forming a polymer on a leadframe comprising the steps of:

providing a leadframe having a top surface and a bottom surface and having an opening formed therein;

providing at least one electronic component coupled to the top surface of the leadframe;

providing a base having a cavity formed therein;

disposing a release film between the substrate and the base;

disposing the leadframe over the base, wherein the top surface of the leadframe is adjacent the base and the at least one electronic component is disposed over the cavity; and

casting through the opening the leadframe a polymer in the cavity of the base, wherein the polymer mates with at least a portion of the leadframe.

8. The method of claim 7 further comprising holding the release film against the cavity before the step of casting the polymer.

9. The method of claim 8 wherein the step of holding comprises providing a hole in the base to the cavity and pulling a vacuum through the hole.

10. The method of claim 7 wherein the step of disposing the release film further comprises disposing a release film comprised of a reflective layer.

11. A method of forming an optoelectronic device, comprising the steps of:

providing a substrate having a front surface and a bottom surface and an opening formed therein;

providing a first and a second optoelectronic device electrically coupled to the front surface of the substrate;

providing a base having a cavity formed therein;

disposing the front surface of the substrate over the base, wherein the first and the second optoelectronic device are disposed over the cavity;

dispensing a polymer in the cavity through the opening in the substrate;

allowing the polymer to take a shape without application of a pressure to form a polymeric body;

pulling the substrate away from the base, wherein the polymeric body mates with at least a portion of the substrate; and

forming a reflective layer over at least a portion of the polymeric body to reflect an optical transmission from the first optoelectronic device to the second optoelectronic device.

12. The method of claim 11 further comprising the step of disposing a release film between the substrate and the base.

13. The method of claim 11 wherein the step of dispensing the polymer comprises dispensing a polymer which is transparent to the optical transmission of the first optoelectronic device.

14. The method of claim 11 wherein the step of forming a reflective layer comprises forming a reflective layer comprised of titanium dioxide.