Plastic package manufacturing for mass volume production is a widely utilized method in the semiconductor industry. By employing lead frames and plastic molding techniques, a variety of package types, including QFN (Quad Flat No-Lead), SOIC (Small Outline Integrated Circuit), QFP (Quad Flat Package), TQFP (Thin Quad Flat Package), PDIP (Plastic Dual In-Line Package), PLCC (Plastic Leaded Chip Carrier), and TSOP (Thin Small Outline Package), can be efficiently manufactured. This introduction provides an overview of the manufacturing process, highlighting the use of lead frames and plastic molding to meet the high-volume production requirements of the industry.
Tooling is a fundamental aspect of plastic package manufacturing. It involves designing and producing the necessary tools and equipment for various stages of the process. This includes:
Lead Frame Design and Production Tooling: Tools used to create the lead frames based on the design specifications, such as stamping dies, etching plates, or photoresist masks.
Mold Tool Design and Production: Tools required for molding the plastic encapsulant, including the mold cavities and associated features specific to each package type.
Molding Equipment: Specialized equipment used during the molding process, such as transfer molding machines that apply heat and pressure to inject the plastic encapsulant into the mold cavities.
II. Lead Frame Design and Production:
Lead frame design is a critical initial step in the manufacturing process. It involves creating precise designs for the metal structures that provide structural support and electrical pathways for the semiconductor devices. The lead frame production process employs techniques such as stamping, etching, or photo-etching to manufacture the lead frames according to the design specifications.
III. Die Attach:
Die attach is a crucial process where the semiconductor die is securely bonded to the lead frame. The die attach step ensures proper alignment and electrical connection between the die and the lead frame. Various techniques and materials, such as adhesive materials or soldering, may be employed depending on the specific requirements of the package.
IV. Wire Bonding:
Wire bonding establishes electrical connections between the die and the lead frame. It enables signal transmission from the die to the external circuits. Wire bonding techniques, such as ball-wedge or wedge-wedge bonding, are utilized to create reliable electrical connections using fine wires made of materials like gold or copper.
The molding process encapsulates the lead frame, die, and wire bonds with a protective plastic compound. This step ensures the physical and environmental protection of the semiconductor device. The plastic encapsulant is injected under pressure into a mold cavity created by the mold tool, which is then solidified, forming the final package.
Marking plays a crucial role in identifying and providing essential information about the package. This step involves laser or inkjet printing of part numbers, logos, date codes, and other relevant information on the package. The marking helps with identification and traceability of the manufactured packages.
VII. Trim and Form (for select package types):
For certain package types, such as those requiring lead customization, a trim and form process is employed. This step involves cutting the leads to their final length and shaping them into their desired configuration. Trim and form ensures compatibility with surface-mount technology (SMT) and facilitates the efficient assembly of the packages onto printed circuit boards.
By ensuring proper tooling and following these essential process steps, semiconductor manufacturers can efficiently produce a variety of plastic packages for mass volume production, meeting the demands of the industry while maintaining high quality and reliability.