Technical Library | 2024-06-19 15:23:54.0
Each year the semiconductor industry routes a significant volume of devices to recycling sites for no reliability or quality rationale beyond the fact that those devices were stored on a warehouse shelf for two years. This study identifies the key risks attributed to extended storage of devices in uncontrolled indoor environments and the risk mitigation required to permit safe shelf-life extension. Component reliability was evaluated after extended storage to assure component solderability, MSL stability and die surface integrity. Packing materials were evaluated for customer use parameters as well as structural integrity and ESD properties. Results show that current packaging material (mold compound and leadframe) is sufficiently robust to protect the active integrated circuits for many decades and permit standard reflow solder assembly beyond 15 years. Standard packing materials (bags, desiccant, and humidity cards) are robust for a 32 month storage period that can be extended by repacking with fresh materials. Packing materials designed for long term storage are effective for more than five years.
Technical Library | 2015-06-11 21:20:29.0
The use of bottom terminated components (BTC) has become widespread, specifically the use of Quad Flat No-lead (QFN) packages. The small outline and low height of this package type, improved electrical and thermal performance relative to older packaging technology, and low cost make the QFN/BTC attractive for many applications.Over the past 15 years, the implementation of the QFN/BTC package has garnered a great amount of attention due to the assembly and inspection process challenges associated with the package. The difference in solder application parameters between the center pad and the perimeter pads complicates stencil design, and must be given special attention to balance the dissimilar requirements
Technical Library | 2008-06-25 16:11:51.0
Printing technologies provide a simple solution to build electronic circuits on o low cost flexible substrates. Nanocomposites will play important role for developing advanced printable technology. Advanced printing is relatively new technology and need more characterization and optimization for practical applications. In the present paper, we examine the use of nanocomposites or materials in the area of printing technology.
Technical Library | 2001-04-24 10:38:38.0
Many PCB designers are interested in taking advantage of Multichip Modules, but are unfamiliar with the technology. While the design process is very much the same, MCM manufacturing processes vary dramatically. MCM routing requirements are dictated by the manufacturing process and types of components. Components mounted on MCM substrates are predominantly, if not exclusively, bare chips. As a result, the component body and I/O pins are no longer constrained to industry standard pin counts and form factors as are packaged components...
Technical Library | 2014-02-20 15:59:17.0
In this chapter, we discuss the type of parts used to create counterfeits and the defects/degradations inherent in these parts due to the nature of the sources they come from, proposed inspection standards, and limitations of these standards. The processes used to modify the packaging of these parts to create counterfeits are then discussed along with the traces left behind from each of the processes. We then present a systematic methodology for detecting signs of possible part modifications to determine the risk of a part or part lot being counterfeit.
Technical Library | 2021-12-21 23:01:30.0
High density PWB (printed wiring board) with microvia technology is required for implementation of high density and high I/O area array packages (AAP). COTS (commercial off-the-shelf) AAP packaging technologies in high reliability versions with 1.27 mm pitch are now being considered for use in a number of NASA systems including the Space Shuttle and Mars Rovers. NASA functional system designs are requiring ever more denser AAP packages and board features, making board microvia technology very attractive for effectively routing a large number of package inputs/outputs.
Technical Library | 2010-01-06 22:27:03.0
Increased functionality and performance requirements for microprocessors and ASICs have resulted in a trend to package these devices in the flip-chip BGA form factor (FCBGA). Because these devices use in excess of 40-100 Watts of power, their packages must dissipate heat in an extremely efficient manner. Most semiconductor companies have developed some type of thermally enhanced FCBGA package that provides heat dissipation through the back of the die to a heat spreader.
Technical Library | 2017-08-31 13:43:48.0
Wire bonded packages using conventional copper leadframe have been used in industry for quite some time. The growth of portable and wireless products is driving the miniaturization of packages resulting in the development of many types of thin form factor packages and cost effective assembly processes. Proper optimization of wire bond parameters and machine settings are essential for good yields. Wire bond process can generate a variety of defects such as lifted bond, cracked metallization, poor intermetallic etc. NSOP – non-stick on pad is a defect in wire bonding which can affect front end assembly yields. In this condition, the imprint of the bond is left on the bond pad without the wire being attached. NSOP failures are costly as the entire device is rejected if there is one such failure on any bond pad. The paper presents some of the failure modes observed and the efforts to address NSOP reduction
Technical Library | 2015-01-28 17:39:34.0
Stacking heterogeneous semiconductor die (memory and logic) within the same package outline can be considered for less complex applications but combining the memory and processor functions in a single package has compromised test efficiency and overall package assembly yield. Separation and packaging the semiconductor functions into sections, on the other hand, has proved to be more efficient and, even though two interposers are required, more economical. The separated logic and memory sections are configured with the same uniform outline for vertical stacking (package-on-package). The most common configuration places the logic section as the base with second tier memory section soldered to a mating contact pattern. This paper addresses the primary technological challenges for reducing contact pitch and package-on-package interface technology.
Technical Library | 2023-08-04 15:38:36.0
The MicroLeadFrame® (MLF®)/Quad Flat No-Lead (QFN) packaging solution is extremely popular in the semiconductor industry. It is used in applications ranging from consumer electronics and communications to those requiring high reliability performance, such as the automotive industry. The wide acceptance of this packaging design is primarily due to its flexible form factors, size, scalability and thermal dissipation capabilities. The adaptation and acceptance of MLF/QFN packages in automotive high reliability applications has led to the development of materials and processes that have extended its capabilities to meet the performance and quality requirements. One of process developments that is enabling the success of the MLF/QFN within the automotive industry has been the innovation of side wettable flanks that provide the capability to inspect the package lead to printed circuit board (PCB) interfaces for reliable solder joints. Traditionally, through-board X-ray was the accepted method for detecting reliable solder joints for leadless packages. However, as PBC layer counts and routing complexities have increased, this method to detect well-formed solder fillets has proven ineffective and incapable of meeting the inspection requirements. To support increased reliability and more accurate inspection of the leadless package solder joints, processes to form side-wettable flanks have been developed. These processes enable the formation of solder fillets that are detectable using state-of-the-art automated optical inspection (AOI) equipment, providing increased throughput for the surface mount technology (SMT) processes and improved quality as well.
