Technical Library | 2023-01-17 17:58:36.0
Heterogeneous integration has become an important performance enabler as high-performance computing (HPC) demands continue to rise. The focus to enable heterogeneous integration scaling is to push interconnect density limit with increased bandwidth and improved power efficiency. Many different advanced packaging architectures have been deployed to increase I/O wire / area density for higher data bandwidth requirements, and to enable more effective die disaggregation. Embedded Multi-die Interconnect Bridge (EMIB) technology is an advanced, cost-effective approach to in-package high density interconnect of heterogeneous chips, providing high density I/O, and controlled electrical interconnect paths between multiple dice in a package. In emerging architectures, it is required to scale down the EMIB die bump pitch in order to further increase the die-to-die (D2D) communication bandwidth. Aa a result, bump pitch scaling poses significant challenges in the plated solder bump reflow process, e.g., bump height / coplanarity control, solder wicking control, and bump void control. It's crucial to ensure a high-quality solder bump reflow process to meet the final product reliability requirements. In this paper, a combined formic acid based fluxless and vacuum assisted reflow process is developed for fine pitch plated solder bumping application. A high-volume production (HVM) ready tool has been developed for this process.
Technical Library | 2023-09-07 14:38:31.0
A repeat customer specializing in high-technology interconnect, sensor, and antenna solutions, partnered with us to dispense small volumes of solder paste (Indium 10.1 SAC305 T6SG 78%m) onto backplane connectors – gold pads 0.175mm x 0.225mm. We performed a test requiring 0.200mm diameter or smaller dots to demonstrate the dispensing capability required.
Technical Library | 2023-12-15 03:06:24.0
The first process in the SMT industry is solder paste printing. After the solder paste printing is completed, electronic components are attached to PCB pads through a SMT machine, and then reflow soldered. A preliminary PCB board is roughly processed. SMT is a combination of multiple devices, and such a line is called an SMT production line. Our common PCBA is processed through this process. In SMT technology, each process is very important, and poor quality can be caused by different process defects. Today, we are discussing the causes and countermeasures of SMT printing collapse.
Technical Library | 2007-02-01 10:08:40.0
The increased replacement of high lead count SMT devices with BGAs and other high ball count area array packages has brought increased challenges to PCB rework and repair. Often solder mask areas surrounding BGA pad areas are damaged when components are removed.
Technical Library | 2007-08-16 13:34:31.0
While experienced inspectors may be able to determine the aesthetic differences between a lead-free PCB assembly and a tin-lead version, one cannot rely on the "experienced eye". "Less wetting out to the pad edges" (Figure A) and "graininess and lack of shininess of the solder joint" (Figure B) are typical comments about some lead-free solder joints. However, in cases where a Nitrogen atmosphere was present during the reflow of the solder joint (Figure C), there will be little visual differences between the lead free alloys and their tin-lead counterparts.
Technical Library | 2007-01-31 15:17:04.0
The goal of this project is to evaluate the reliability of lead-free BGA solder joints with a variety of different pad sizes using several different BGA rework methods. These methods included BGAs reworked with both flux only and solder paste attachment techniques and with or without the use of the BEST stay in place StencilQuick™. The daisy chained test boards were placed into a thermal test chamber and cycled between -25ºC to 125ºC over a 30 minute cycle with a 30 minute dwell on each end of the cycle. Each BGA on the board was wired and the continuity assessed during the 1000 cycles the test samples were in the chamber.
Technical Library | 2022-07-11 09:24:48.0
The change of squeegee pressure has a significant impact on printing. Too small pressure will make the solder paste unable to effectively reach the bottom of the stencil opening and not be well deposited on the pad. Too much pressure will cause tin The paste is printed too thin and can even damage the stencil.
Technical Library | 2013-01-17 15:34:33.0
The use of an electroless nickel, immersion gold (ENIG) surface finish comes with the inherent potential risk of Black Pad failures that can cause fracture embrittlement at the interface between the solder and the metal pad. As yet, there is no conclusive agreed solution to effectively eliminate Black Pad failures. The case studies presented are intended to add to the understanding of the Black Pad failure mechanism and to identify both the plating and the subsequent assembly processes and conditions that can help to prevent the likelihood of Black Pad occurring.
Technical Library | 2023-05-22 16:49:42.0
Our customers' issues • Apertures are getting smaller • Paste does not release as well • Contaminates the bottom of the stencil • Increases defects / reduces yield Insufficient solder Bridging Solder balls on surface of PCB Flux residue • Requires more frequent cleaning • Reduced efficiency (wasted time) • Increased use of consumables (cost) USC fabric (use "cheap" fabric to reduce cost) Lint creates more defects Cleaning chemistries (use IPA to reduce cost) IPA breaks down flux and can create more defects
Technical Library | 2015-08-13 15:52:40.0
Pad cratering has become more prevalent with the switch to lead free solders and lead free compatible laminates. This mainly is due to the use of higher reflow temperature, stiffer Pb-free solder alloys, and the more brittle Pb-free compatible laminates. However, pad cratering is difficult to detect by monitoring electric resistance since pad cratering initiates before an electrical failure occurs. Several methods have been developed to evaluate laminate materials' resistance to pad cratering. Pad-solder level tests include ball shear, ball pull and pin pull. The detailed methods for ball shear, ball pull, and pin pull testing are documented in an industry standard IPC-9708. Bansal, et al. proposed to use acoustic emission (AE) sensors to detect pad cratering during four-point bend test. Currently there is an industry-working group working on test guidelines for acoustic emission measurement during mechanical testing.
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