C4NP as a High-Volume Manufacturing Method for Fine-Pitch and Lead-Free FlipChip Solder Bumping

Author(s):  
Eric Laine ◽  
Klaus Ruhmer ◽  
Eric Perfecto ◽  
Hai Longworth ◽  
David Hawken
Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3353
Author(s):  
Marina Makrygianni ◽  
Filimon Zacharatos ◽  
Kostas Andritsos ◽  
Ioannis Theodorakos ◽  
Dimitris Reppas ◽  
...  

Current challenges in printed circuit board (PCB) assembly require high-resolution deposition of ultra-fine pitch components (<0.3 mm and <60 μm respectively), high throughput and compatibility with flexible substrates, which are poorly met by the conventional deposition techniques (e.g., stencil printing). Laser-Induced Forward Transfer (LIFT) constitutes an excellent alternative for assembly of electronic components: it is fully compatible with lead-free soldering materials and offers high-resolution printing of solder paste bumps (<60 μm) and throughput (up to 10,000 pads/s). In this work, the laser-process conditions which allow control over the transfer of solder paste bumps and arrays, with form factors in line with the features of fine pitch PCBs, are investigated. The study of solder paste as a function of donor/receiver gap confirmed that controllable printing of bumps containing many microparticles is feasible for a gap < 100 μm from a donor layer thickness set at 100 and 150 μm. The transfer of solder bumps with resolution < 100 μm and solder micropatterns on different substrates, including PCB and silver pads, have been achieved. Finally, the successful operation of a LED interconnected to a pin connector bonded to a laser-printed solder micro-pattern was demonstrated.


2013 ◽  
Vol 2013 (1) ◽  
pp. 000420-000423
Author(s):  
Kwang-Seong Choi ◽  
Ho-Eun Bae ◽  
Haksun Lee ◽  
Hyun-Cheol Bae ◽  
Yong-Sung Eom

A novel bumping process using solder bump maker (SBM) is developed for fine-pitch flip chip bonding. It features maskless screen printing process with the result that a fine-pitch, low-cost, and lead-free solder-on-pad (SoP) technology can be easily implemented. The process includes two main steps: one is the thermally activated aggregation of solder powder on the metal pads on a substrate and the other is the reflow of the deposited powder on the pads. Only a small quantity of solder powder adjacent to the pads can join the first step, so a quite uniform SoP array on the substrate can be easily obtained regardless of the pad configurations. Through this process, an SoP array on an organic substrate with a pitch of 130 μm is, successfully, formed.


Author(s):  
S. Manian Ramkumar ◽  
Krishnaswami Srihari

The electronics industry, in recent years, has been focusing primarily on product miniaturization and lead-free assembly. The need for product miniaturization is due to the continuous demand for portable electronic products that are multifunctional, yet smaller, faster, cheaper, and lighter. This is forcing the industry to design and assemble products with miniature passive and active devices. These devices typically have fine pitch footprints that provide a very small surface area for attachment. The solder attach technique relies primarily on the formation of intermetallics between the mating metallic surfaces. With a reduction in the surface area of the pads, the ratio of intermetallic to solder is very high once the solder joint is formed. This could result in unreliable solder joints, due to the brittle nature of intermetallics. In addition, the need to eliminate lead-based materials as a means of interconnection has renewed the industry’s interest in exploring other means of assembling surface mount devices reliably. This paper discusses the performance characteristics and preliminary research findings pertaining to a novel Anisotropic Conductive Adhesive (ACA) for electronics packaging applications, utilizing the Z Bond™ technology from Nexaura Systems, LLC. Typically, ACAs require the application of pressure during the curing process, to establish the electrical connection. The novel ACA uses a magnetic field to align the particles in the Z-axis direction and eliminates the need for pressure during curing. The formation of conductive columns within the polymer matrix provides a very high insulation resistance between adjacent conductors. The novel ACA also enables mass curing of the adhesive, eliminating the need for sequential assembly. The novel ACA’s I-V characteristics and performance under thermal and temperature-humidity aging are discussed in detail.


2016 ◽  
Vol 22 (4) ◽  
pp. 735-742 ◽  
Author(s):  
Tomaz Brajlih ◽  
Matej Paulic ◽  
Tomaz Irgolic ◽  
Ziga Kadivnik ◽  
Joze Balic ◽  
...  

Purpose This paper aims to present a comparison between selective laser sintering and injection moulding technology for the production of small batches of plastic products. Design/methodology/approach The comparison is based on analysing the time–cost efficiencies of each manufacturing process regarding the size of the series for the selected product sample. Both technologies are described and the times and costs of those individual processes needed to create a final product are assessed when using each of the manufacturing processes. Findings The study shows that the time-cost efficiency of the selected laser sintering technology increases according to the complexity of the product and decreases with increasing series size and product volume. Research limitations/implications The study and absolute values of the presented results are limited to a selected plastic product, but the series size-focused efficiency analysis could be expanded to general cases. Originality/value The presented analysis could be used as a general guideline for a decision-making process regarding the more efficient manufacturing method. In addition, the results show the viability of using selective laser sintering during the early stages of production when fast product availability is required, regardless of the series size. Also, some complementary effects of using both technologies in the serial production of the same part are discussed.


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