Cavity type pressure sensor device

• US 9,890,034 B2
• Filed: 11/30/2016
• Issued: 02/13/2018
• Est. Priority Date: 06/20/2016
• Status: Expired due to Fees

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Bai, Zhigang, Wang, Zhijie, Yao, Jinzhong
• Primary Examiner(s): Diaz, Jose R
• Application Number:
  US15/364,273
• Publication Number:
  US 20170362077A1
• Time in Patent Office: 440 Days
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 7/0038 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81B 7/0058 for protecting against damages due to external chemical or mechanical influences, e.g. shocks or vibrations
• CPC Class Codes: B81C 1/00285 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: G01L 19/0076 using buried connections
• CPC Class Codes: G01L 19/0092 Pressure sensor associated with other sensors, e.g. for measuring acceleration or temperature G01L9/025, G01L9/045, G01L9/065, G01L9/085, G01L9/105, G01L9/125, G01L19/02, G01L19/04 take precedence; measuring two or more variable G01D21/02; temperature sensors with pressure compensation G01K1/26
• CPC Class Codes: G01L 19/0627 Protection against aggressive medium in general
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48095 Kinked
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 23/24 solid or gel at the normal operating temperature of the device H01L23/3135 takes precedence
• CPC Class Codes: H01L 23/3135 Double encapsulation or coating and encapsulation
• 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 2924/1815 Shape

Abstract

A semiconductor sensor device is assembled using a lead frame having a flag surrounded by lead fingers. A pressure sensor die is mounted on the flag and electrically connected to the leads. Prior to encapsulation, a pre-formed block of gel material is placed over the sensor region on the die. Encapsulation is performed and mold compound covers the pressure sensor die and the bond wires. Mold compound covering the gel block may be removed. Additionally, a trench may be formed around an upper portion of the gel block so that the lateral sides of the gel block are at least partially exposed.

Claims

1. A method for assembling a semiconductor sensor device, the method comprising:

attaching a pressure sensor die to a flag of a lead frame;

electrically connecting the pressure sensor die to first leads of the lead frame with first bond wires;

placing a pre-molded block of gel material over an active region of the pressure sensor die; and

encapsulating the pressure sensor die and the first bond wires with a mold compound, wherein the mold compound at least partially covers the block of gel material,

wherein an upper surface of the block of gel material is flush with a top surface of the mold compound and exposed.

2. The method of claim 1, further comprising forming a trench around the gel block, wherein lateral sides of the gel block are at least partially exposed.

3. The method of claim 2, wherein the upper surface of the gel block lies below the top surface of the mold compound.

4. The method of claim 2, wherein a layer of the mold compound covers the upper surface of the gel block.

5. The method of claim 1, wherein the upper surface of the gel block is flush with a lower surface of the trench and the lateral sides of the gel block abut the mold compound.

6. The method of claim 1, further comprising:

forming the gel block using a transfer molding process and a dedicated mold cavity matching the shape of the gel block; and

attaching the gel block to the active region of the pressure sensor die with an adhesive.