Silver Metallization of Polyimide Surfaces Using EnvironmentallyFriendly Reducing Agents

Two environmentally friendly reducing agents, ascorbic acid and glucose, were employed to fabricate Ag-thin-film-coated polyimide(PI) films. Ascorbic acid is an acidic reducing agent, whereas glucose is an alkaline reducing agent. Both of these reducing agentsare capable of reducing Ag+ ions doped in poly(amic acid) (PAA) formed by hydrolysis of a PI surface. Only glucose can producea continuous and dense Ag thin film on a PAA surface. Granular and discontinuous Ag thin films were obtained when ascorbic acidwas employed as a reducing agent. This difference in reactivity is attributed to the pH values of these reducing solutions

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Accelerator Screening by Cyclic Voltammetry for Microvia Fillingby Copper Electroplating

A cyclic voltammetry (CV) screening method is proposed in this work to identify an effective accelerator for the copper superfillingof microvias of a printed circuit board (PCB). Five typical organosulfides are used as model additives to evaluate the performanceof the screening method. The five organosulfides are 3-mercapto-1-propanesulfonate (MPS), bis(3-sulfopropyl) disulfide (SPS),3-mercaptopropionic acid (MPA), 3-mercapto-1-propanol (MPO), and 3,3-thiobis(1-propanesulfonate) (TBPS), where MPS, MPA,and MPO contain a thiol head-group, SPS contains a disulfide group, and TBPS contains a thioether group. MPS, SPS, and TBPShave one or two terminal groups of sulfonates, whereas MPA has a terminal group of carboxylic acid, and MPO has a terminal groupof alcohol. The CV screening method revealed that MPS, SPS, and TBPS are accelerators for copper electrodeposition and thatMPA and MPO are not. A specific copper deposition peak, specifically, the α peak, that appears in the CV patterns is an indicatorfor accelerator screening. This study is the first to indicate that TBPS with a thioether group rather than a thiol group can acceleratecopper electrodeposition and can be used for the copper superfilling of the microvias of a PCB

Highly Selective Cu Electrodeposition for Filling Through Silicon Holes

In this work, a copper plating formula that can directly and selectively fill the through silicon holes (TSHs) for 3D chip stacking packaging was developed. The copper plating technology reduced and simplified the process steps for fabricating through silicon vias (TSVs) and TSHs. The highly selectivity of copper fill in the TSHs also reduced the manufacture cost of 3D chip stacking packaging, because the copper plating technology reduced the loading of a post-copper chemical mechanical polishing (CMP) and did not need a post-thermal annealing treatment. The copper plating formula was very simple, just containing single organic additive

Effects of supporting electrolytes on copper electroplating for filling through-hole

The filling of micron through-holes (THs) in a printed circuit board (PCB) by copper electroplating was investigated in this study. The role of supporting electrolytes, such as H2SO4, Na2SO4 and K2SO4, was explored using practical TH filling plating and linear-sweep voltammetry (LSV) analysis of plating solutions. The copper could selectively fill THs using one organic additive, namely, tetranitroblue tetrazolium chloride (TNBT), as an inhibitor. The inhibiting strength of TNBT depended on the supporting electrolytes. Although H2SO4 could enhance the inhibiting strength of TNBT, it also decreased the filling capability of the copper plating solution; Na2SO4 and K2SO4 did not enhance the inhibiting strength of TNBT but they increased the filling capability of the copper plating solution. Additionally, the protons could chemically interact with TNBT to form precipitate, whereas sodium and potassium ions did not easily interact with TNBT. The filling capability of the copper plating solution using Na2SO4 and K2SO4 as supporting electrolytes could be greatly improved by adding a small amount of bis(3-sulfopropyl)-disulfide (SPS) and poly(ethylene glycol) (PEG) with a molecular weight of 600

Influence of additives on electroplated copper films and their solder joints

An organosulfide, 3‑(2‑benzthiazolylthio)‑1‑propanesulfonsäure (ZPS), is used as an accelerator and formulated with a suppressor (polyethylene glycol, PEG) and chloride ions (Cl−) in the copper plating solution containing electrolytes (Cu sulfate and sulfuric acid) to prepare the Cu films. Microstructural characterization using focus ion beam (FIB), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) reveals that an increase of the ZPS concentration accelerates the grain growth of the electroplated Cu films. Impurity examination based on time-of-flight secondary ion mass spectrometer (TOF-SIMS) shows that such microstructural evolution effectively suppresses the impurity incorporation in the electroplated Cu films. The suppression effect on impurity incorporation by using a high level of ZPS concentration plays an important role in retaining the microstructural stability and integrity of the electroplated Cu solder joints subjected to thermal aging

METHOD FOR SYNTHESIS OF METAL NANOPARTICLES

一種奈米金屬粒子之合成方法,其步驟包含選用一摻有金屬離子之固態聚亞醯胺酸,且選用具有一添加劑之一還原液,而將該聚亞醯胺酸置入一還原液中。還原液可將金屬離子還原至聚亞醯胺酸,而還原後的金屬離子可與添加劑產生反應而懸浮於還原液中。藉此,透過前述的異相化學反應可產生均勻粒徑的奈米金屬粒子