1. What is opto-electronic packaging? Opto-Electronic Packaging is the physical realization of electronic and information technology products and systems. These products (or systems) have input and output functions. They require energy to operate and generate waste heat that must be removed.

2. What are the main functions of opto-electronic packaging ?The primary functions of opto-electronic packaging are: Signal Distribution including Input/Output Electrical interconnection Optical interconnection Power Distribution including Input/Output Electrical interconnection Mechanical interconnection. Heat dissipation. Housing and protection: Temperature, humidity, dust, shock & vibration environment during shipping, handling and customer usage.

3. List the various levels of interconnection in electronic packaging. Integrated Circuit (IC) Package - the silicon chip is housed in an IC package; electrical connections are made by thin gold, copper or aluminum wires (first level of interconnection).

Printed circuit board - IC packages are placed on a circuit board and electrically connected together (second level) with photo-etched conductor traces, typically made of copper

Connectors on the circuit boards are inserted into contacts on a backplane, providing interconnection between the different circuit boards.

The backplane & the circuit boards are housed in a shelf or a housing Several shelves (or housings) along with power supplies and cables are housed in a cabinet.

A cabinet may be a stand-alone product or several cabinets may be connected together by cables to form a larger system.

Several large systems may be connected together to form a network, for example, the telephone network or the IP network.

4. Make a list of the opto-electronic packaging building blocks from the first or the smallest level to the whole communication network.

Level 0: IC chip (die)Level 1: Packaged chipLevel 2: Printed BoardLevel 3: Card-on-boardLevel 4: CabinetLevel 4: System

5. What are the key driving forces on electronic packaging design and manufacture? Cost (cheaper). Performance (more functions & faster). Size (smaller, lighter) Reliability (more rugged and less prone to down time) Manufacturabilty. (can be manufactured in high volume, with high yield, with minimum capital investment) Industry standards and open interfaces

6. What is a through-hole IC package? List the various types of through-hole IC packages. Through-hole Single in line packages (SIPs) Dual in line packages (DIPs). Pin grid arrays (PGAs). 7. What is a surface mount IC package? List the various types of surface mount packages. Surface mount. Leadless chip carriers (QFNs) Leaded chip carriers. Quad flat packs (QFPs). Small outline packages (SO). Ball Grid Arrays (BGAs). TAB (Tape automated bonding)8. List the different types of IC packaging technologies commonly used in industry. Number them in order of increasing cost, 1 being the lowest cost 9. List the assembly sequence of the most commonly used IC packaging technology starting with wafer saw to a shippable device. List the approximate temperature of each process in the assembly sequence. Wafer Saw

Wafer Sort

Die Attach (Mechanical attachment of chip to package)Chip attached to copper leadframe with silver filled epoxy, cured at 175C

Electrical Connection Chip to PackageGold wire, 25 to 30 micron diameter, thermo-sonic bond.(Copper wire is beginning to replace gold)

Package Seal or EncapsulationMold with epoxy. Cured at 175C.

Lead FinishLeads solder or tin plated, trimmed, and formed.

Visual inspection

Electrical Test

Burn In

Final Electrical Test

Final Inspection & Ship

10. What are the advantages and disadvantages of through hole versus surface mount package in circuit board design and assembly? What has been the industry trend?

11. What is a hermetic IC package? Non-hermetic IC package? Give examples.12. What are the consequences of using epoxy or any other organic substance as a chip attach material in a hermetic IC package.