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Semiconductor Module Encapsulant-Dispensing Technique

IP.com Disclosure Number: IPCOM000048010D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Starr, SG: AUTHOR

Abstract

This is an improved technique for sealing a semiconductor package with an encapsulant, such as SCOTCHCAST*. The need for hermetically sealing semiconductor integrated circuit packages is well known, as is the need to contain the encapsulant material. One such technique was described in the IBM Technical Disclosure Bulletin, 23, 5042 (April 1981), in which a two-step encapsulating process was proposed to prevent sealant material from running into the interior surface of the module. The present technique is also a two-stage process. Illustrated in Fig. 1 is a top view of a corner of ceramic substrate 10 and outer package (usually metal can) 12. Solder balls 14 form electrical and mechanical connections to a second ceramic substrate.

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Semiconductor Module Encapsulant-Dispensing Technique

This is an improved technique for sealing a semiconductor package with an encapsulant, such as SCOTCHCAST*. The need for hermetically sealing semiconductor integrated circuit packages is well known, as is the need to contain the encapsulant material. One such technique was described in the IBM Technical Disclosure Bulletin, 23, 5042 (April 1981), in which a two-step encapsulating process was proposed to prevent sealant material from running into the interior surface of the module. The present technique is also a two-stage process. Illustrated in Fig. 1 is a top view of a corner of ceramic substrate 10 and outer package (usually metal can) 12. Solder balls 14 form electrical and mechanical connections to a second ceramic substrate. It has been found that by dispensing the sealant material 20 at each of the four corners, it is confined only to the space between the can 12 and substrate 10 and fills only the area between the substrate and the can by following a direction of travel between the corners indicated by the arrows. Fig. 2 is a side view illustrating the area filled by the sealant 20. Also shown in Fig. 2 are pins 30 that normally penetrate ceramic substrate 10. Also illustrated is second ceramic substrate 40 joined to the ceramic substrate 10 by means of solder balls 14. The entire module is preheated to approximately 130OEC to achieve the desired result. If the temperature is too low, the viscosity of...