| US5355016A | 1994-10-11 | |||
| US8080880B2 | 2011-12-20 | |||
| US6365978B1 | 2002-04-02 |
| What is claimed is: 1. Par lene-coated, ultra ruggedized ball grid array electronic components comprise a substrate with electronic components attached to one surface, and solder balls attached to a second surface of said substrate through openings that are smaller than the diameter of the solder balls placed in said openings formed in said parylene coating. 2. The components of claim 1 wherein said components include dies and wirebonds, said substrate is a rectangular block, and said electronic components and said solder balls are on opposite side of said block. 3. Parylene-coated, ultra ruggedized ball grid array electronic components comprise a substrate with electronic components attached to one surface, and solder balls melted and sealed to a second surface of said substrate through openings in said second surface formed in said parylene coating. |
This invention comprises ultra ruggedized ball grid array electronic components that are resistant to degradation from humidity and from pressure. These components are externally coated with parylene, and include openings through the parylene coating at their base to receive solder balls. Parylene is a tradename for a plurality of chemical vapor deposited poly(p- xylylene) polymers, such as the polymers called parylene C, parylene N, parylene AF-4 parylene SF, parylene D, parylene A, parylene AM, parylene CF, and parylene HT.
In some embodiments, these components may include a substrate, with one or more dies and wirebonds mounted on the substrate. Molding material may cover the dies and wirebonds to hold them in place on the substrate, and to insulate them from the environment. Making these embodiments includes the steps of: coating the ball grid array with parylene; laser ablating a surface of the array to form openings to receive solder balls; and placing solder balls in each of the openings so formed. Preferably, the solder openings are smaller than the solder balls to facilitate formation of a seal after the solder is melted.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate an example, or embodiment, of an ultra ruggedized ball grid array electronic component, and include:
Figure 1, showing a side elevation view of this array; and
Figure 2, showing manufacture of the array of Figure 1. DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 shows a side elevation view in cross-section of an exemplary array 10. This array includes substrate 11 with dies 12 and wirebonds 13 mounted on substrate.11. Molding 14 covers dies 12 and wirebonds 13, holding them in place on substrate 11, and insulating them from the environment. Parylene coating covers the entire external surface of array 10, except for the openings 16 in which are solder balls 17. Wirebond pads 40 affix leads 13 to solder pads 17.
Figure 2 shows the manufacture of array 10. At step 18, uncoated array is passed to step 19, where a parylene coating is applied to the entire external surface of the array. At the next step 20, openings are formed in the parylene coating on the substrate at solder pad openings 22 in substrate 11 via laser ablation. Each opening is smaller in length than the diameter of the solder ball so that the solder, after melting, seals the corresponding opening. At the next step 21 , solder balls are placed in openings 22.
The above-described embodiment of this invention is exemplary, and is not meant to limit the scope of the claims.
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