Integrated sensor packages and methods of making the same

• US 6,917,089 B2
• Filed: 04/22/2004
• Issued: 07/12/2005
• Est. Priority Date: 05/11/2001
• Status: Active Grant

• Current Assignee: Melexis Technologies SA
• Original Assignee: Melexis NV (Sensinnovat BVBA)
• Inventors: Hill, Adrian, Betts, William R., Diels, Roger, Schuurmans, Johan
• Primary Examiner(s): Nhu, David
• Application Number:
  US10/831,489
• Publication Number:
  US 20040197957A1
• Time in Patent Office: 446 Days
• Field of Search: 257/427, 257/100, 257/113, 257/114, 257/116, 257/421, 257/424, 257/428, 257/431, 257/432, 257/433, 257/528
• US Class Current: 257/427
• CPC Class Codes: B29C 33/06 using radiation , e.g. electro-magnetic waves, induction heating
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• CPC Class Codes: H01L 21/50 Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 23/315 the encapsulation having a cavity
• 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 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80

Abstract

Elements of a sensor system are encapsulated into a single package. The sensor elements are covered with a flexible gel coat and then inserted into a molding tool cavity. Each element may be individually coated with a gel blob, or all elements may by coated with a single gel blob. One or more retractable pins are incorporated into the molding tool and in their normal position are each in contact with the gel. A molding compound is injected into the cavity so as to encapsulate the device and gel coat. When the pins are extracted and the device ejected from the molding cavity, one or more passageways in the molding are left defined by the pins. The passageways expose the flexible gel covering the device elements to the atmosphere. For pressure sensitive elements, the gel, being flexible, transfers the local air pressure to the pressure sensitive element. For optical elements, the exposed gel is preferably removed to allow for the passage of radiation to and from the device elements. Alternatively, or in addition, an optically transmitting gel is used so as to allow for the passage of radiation at specific wavelengths.

Claims

1. An encapsulated integrated sensor device, formed by:

providing an integrated circuit, the integrated circuit including a sensing element;

applying a quantity of gel to the integrated circuit such as to cover at least the sensing element, thereby forming a gel-covered assembly;

inserting the gel-covered assembly into a cavity of a molding tool;

attaching a retractable pin to the gel-covered assembly;

introducing a plastic mold compound into the cavity so as to encapsulate the gel-covered assembly and at least a portion of the retractable pin; and

removing the retractable pin from the gel such as to leave a passageway in the plastic mold compound encapsulating the gel-covered assembly, thereby exposing the gel to an atmosphere through the passageway.

2. The device of claim 1, wherein the sensing element includes one of a pressure sensing element and a radiation sensing element.

7. The device of claim 1, wherein a shape of the retractable pin is configured to correspond with a shape of the sensing element.

8. The device of claim 1, wherein the pin is oriented such that the passageway in the plastic mold compound aligns the sensing element with an intended target position external to the plastic mold compound.

9. The device of claim 1, further formed by filling the passageway with an optically transparent gel.

10. The device of claim 1, further formed by mounting an optically transparent window so as to seal the passageway.

3. An encapsulated integrated sensor device, formed by:

providing an integrated circuit, the integrated circuit including a radiation sensing element and a radiation transmission element;

applying a gel to the integrated circuit such as to cover at least the radiation sensing element and the radiation transmission element, thereby forming a gel-covered assembly;

inserting the gel-covered assembly into a cavity of a molding tool;

attaching at least two retractable pins to the gel-covered assembly, a first pin contacting the gel at a location proximal the radiation sensing element and a second pin contacting the gel at a location proximal the radiation transmission element;

introducing a plastic mold compound into the cavity so as to encapsulate the gel-covered assembly and at least a portion of each pin; and

removing the first and second pins from the gel such as to leave passageways in the plastic mold encapsulating the gel-covered assembly, thereby exposing the gel to an atmosphere through the passageways.

4. The device of claim 3, wherein a shape of the first pin is configured so as to correspond with a shape of the radiation sensing element and wherein a shape of the second pin is configured so as to correspond to a shape of the radiation transmission element.

5. The device of claim 3, wherein the orientation of the first pin is arranged such that a first passageway in the plastic mold encapsulating the gel-covered assembly aligns the radiation sensing element with an intended target, and wherein the orientation of the second pin is arranged such that a second passageway in the plastic mold encapsulating the gel-covered assembly aligns the radiation transmission element with the intended target.

6. The device of claim 3, wherein the first and second pins are each oriented such that first and second passageways in the plastic mold encapsulating the gel-covered assembly (package) align the radiation sensing element and radiation transmission element, respectively, with an intended target position external to the package.