Locking of mold compound to conductive substrate panels

• US 6,576,989 B1
• Filed: 11/28/2000
• Issued: 06/10/2003
• Est. Priority Date: 11/28/2000
• Status: Expired due to Fees

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Yeen, Chan Peng, Bayan, Jaime, Nadarajah, Santhiran, Wan, Sharon Ko Mei, Lek, Hu Ah, Spalding, Peter Howard, Hong, Harry Kam Cheng
• Primary Examiner(s): Zarabian, Amir
• Assistant Examiner(s): Soward, Ida M.
• Application Number:
  US09/724,727
• Time in Patent Office: 924 Days
• Field of Search: 257/678, 257/683, 257/704, 257/723, 257/685, 257/731, 257/680
• US Class Current: 257/678
• CPC Class Codes: H01L 23/13 characterised by the shape
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• 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 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

A panel assembly of packaged integrated circuit devices including conductive substrate panel having an array of device areas and a plurality of locking passageways. The locking passageways are positioned about an inactive buffer area which surrounds the periphery of the array of device areas. The locking passageways extend from a topside of the panel toward a bottom side of the panel. The panel assembly also includes a molded cap that is molded over the topside of the panel to encapsulate the array of device areas and the inactive buffer area. The molded cap includes conforming locking stem portions that extend into each of the locking passageways in a manner locking the molded cap to the substrate panel such that during singulation of the device areas, the molded cap will not separate from the substrate panel at the inactive buffer area. In another aspect of the invention, a method for producing the panel assembly having the locking passageways is described. The method involves providing a conductive substrate panel having the locking passageways and applying molding material to the topside of the substrate panel such that the solidified molding material forms stems that conform to the passageways.

Claims

1. A panel assembly of packaged integrated circuit devices comprising:

a conductive substrate panel having at least one array of device areas, and defining a plurality of locking passageways positioned about an inactive buffer area which surrounds the periphery of the array of device areas, said locking passageways extending inwardly from a topside of the panel toward a bottom side thereof; and

a molded cap that is molded over the panel topside to encapsulate the device areas of the array and the inactive buffer area, said molded cap further having integrally formed, conforming locking stem portions that extend into each of the locking passageways such that each of the locking stems have substantially the same shape and size as the locking passageway into which each of the locking stems extend, the locking stems configured to lock the molded cap to the substrate panel such that during singulation of the device areas, said molded cap will not separate from the substrate panel at the inactive buffer area.

2. The panel assembly as recited in claim 1 wherein each locking passageway includes a lock section having a transverse cross-sectional dimension larger than that at a topside entrance into the respective locking passageway such that a corresponding lock section of the corresponding stem has a larger transverse cross-sectional dimension than a corresponding section of the stem at the topside entrance into the passageway.

3. The panel assembly as recited in claim 1 wherein each locking passageway has a bottom side entrance that has a cross-sectional dimension larger than that of a topside entrance, the corresponding stem having a cross-sectional dimension at the bottom side entrance that is larger than a cross-sectional dimension at the topside entrance.

4. The panel assembly as recited in claim 1 wherein at least one of the locking passageways defines a transverse cross-sectional area substantially having the shape of an elongated oval, a circle, a square or an “

L”

.

5. The panel assembly as recited in claim 1 wherein at least two of the locking passageways are grouped together such that the at least two locking passageways are positioned proximate to each other.

6. The panel assembly as recited in claim 1 further comprising an adhesive tape that is attached to the mold cap.

7. The panel assembly as recited in claim 1 wherein each of the device areas contains a semiconductor die, a plurality of electrical contacts positioned adjacent to the semiconductor die, and a plurality of interconnecting wires that connect the semiconductor die to each of the electrical contacts.

15. The panel assembly as recited in claim 1 wherein each locking passageway has its smallest width dimension located at some point in between the topside entrance and the bottom side entrance.

16. The panel assembly as recited in claim 1 wherein the locking stem portions of the molded cap fully expand into the locking passageways during the molding process.

19. A panel assembly as recited in claim 15, wherein the topside entrance and the bottom side entrance of each locking passageway have widths larger than the smallest width dimension such that each locking passageway and locking stem have an hourglass shape.

8. A panel assembly for packaged integrated circuit devices having a molded cap comprising:

a conductive substrate panel having at least one array of device areas, and defining a plurality of locking passageways positioned about an inactive buffer area that peripherally surrounds the array of device areas, said locking passageways extending inwardly from a topside of the panel toward a bottom side thereof, wherein when the molded cap is molded over the panel topside to encapsulate the device areas of the array and the inactive buffer area, a conforming locking stem portion is integrally formed with the molded cap and extends into each locking passageway such that each of the locking stems have substantially the same shape and size as the locking passageway into which each of the locking stems extend, the locking stems configured to lock the molded cap to the substrate panel such that during singulation of the device areas, said molded cap will not separate from the substrate panel at the inactive buffer area.

9. The panel assembly as recited in claim 8 wherein each locking passageway includes a lock section having a transverse cross-sectional dimension larger than that at a topside entrance into the respective locking passageway such that a corresponding lock section of the corresponding stem has a larger transverse cross-sectional dimension than a corresponding section of the stem at the topside entrance into the locking passageway.

10. The panel assembly as recited in claim 8 wherein each locking passageway has a bottom side entrance that has a cross-sectional dimension larger than that of a topside entrance, the corresponding stem having a cross-sectional dimension at the bottom side entrance that is larger than a cross-sectional dimension at the topside entrance.

11. The panel assembly as recited in claim 8 wherein at least one of the locking passageways defines a transverse cross-sectional area substantially having the shape of an elongated oval, a circle, a square or an “

L”

.

17. The panel assembly as recited in claim 8 wherein each locking passageway has its smallest width dimension located at a point in between the topside entrance and the bottom side entrance.

18. The panel assembly as recited in claim 8 wherein the locking stem portions of the molded cap fully expand into the locking passageways during the molding process.

20. A panel assembly as recited in claim 17, wherein the topside entrance and the bottom side entrance of each locking passageway have widths larger than the smallest width dimension such that each locking passageway has an hourglass shape.

12. A panel assembly for packaged integrated circuit devices having a molded cap comprising:

a conductive substrate panel having at least one array of device areas, wherein each of the device areas contains a semiconductor die, a plurality of electrical contacts positioned adjacent to each respective semiconductor die, and a plurality of interconnecting wires that connect each respective semiconductor die to each adjacent respective electrical contact, wherein the conductive substrate panel is constructed such that a plurality of locking passageways are positioned around the periphery of the array of device areas, said locking passageways extending inwardly from a top side of the panel towards a bottom side thereof; and

a molded cap that is formed over the panel topside to encapsulate the device areas of the array and the inactive device area, such that the molded cap is bonded to the device area via contact with the devices and such that the molded cap is bonded to the inactive buffer area via integrally formed, conforming locking stem portions of the molded cap that extend into each of the locking passageways such that each of the locking stems have substantially the same shape and size as the locking passageway into which each of the locking stems extend, the locking stems configured to lock the molded cap to the substrate panel such that during singulation of the device areas, the edge portions of the cap will not separate from the substrate panel and the inactive buffer area.

13. The panel assembly as recited in claim 12 wherein each locking passageway has its smallest width dimension located at a point in between the topside entrance and the bottom side entrance.

14. The panel assembly as recited in claim 12 wherein the locking stem portions of the molded cap fully expand into the locking passageways during the molding process.

21. A panel assembly as recited in claim 13, wherein the topside entrance and the bottom side entrance of each locking passageway have widths larger than the smallest width dimension such that each locking passageway and locking stem have an hourglass shape.