scholarly journals The Effect of Cu Target Pad Roughness and Solution Flow on the Growth Mode and Void Formation in Electroless Cu Films

2021 ◽  
Vol 18 (2) ◽  
pp. 40-50
Author(s):  
Tobias Bernhard ◽  
Sebastian Zarwell ◽  
Roger Massey ◽  
Edith Steinhäuser ◽  
Stefan Kempa ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Exchange Rate ◽  
Negative Impact ◽  
Void Formation ◽  
Growth Mode ◽  
Solution Flow ◽  
Cu Substrate ◽  
Cu Films ◽  
Growth Modes ◽  
Spherical Grains

Abstract The effect of the Cu target pad roughness on the growth mode of electroless Cu from two different Cu baths was investigated, with bath A having a cyanide based, and bath B, a non-cyanide-based stabilizer system. Both baths are commonly used within the PCB industry. In the case of bath B, for an average target pad roughness higher than Ra = 300 nm, two growth modes are observed. The first mode is a copying of the subjacent Cu substrate morphology, whereas the second forms spherical grains (Cu-nodules) predominantly at the exposed sites of the substrate crystals. These Cu nodules typically have a radius comparable to that of the plated electroless Cu thickness and contain a high density of nanovoids toward their base. The related void formation seems relevant to weaken the overall Cu/Cu/Cu interconnection in the blind microvia. Interestingly, the tendency to form nodules with increasing Cu base roughness is widely suppressed for the cyanide-based bath A, where the deposit is nodule free up to a target pad roughness of approximately Ra=1,000 nm. When solution delivery and exchange were investigated, it is apparent that a low exchange rate has a negative impact on the electroless Cu deposition, and results with undesirable nodules and voids, even if the surface roughness values would suggest otherwise, could be expected.

The effect of Cu target pad roughness on the growth mode and void formation in electroless Cu films

2020 ◽  
Vol 2020 (1) ◽  
pp. 000291-000297
Author(s):  
Tobias Bernhard ◽  
Sebastian Zarwell ◽  
Edith Steinhäuser ◽  
Stefan Kempa ◽  
Frank Brüning
Keyword(s):  
Void Formation ◽  
High Density ◽  
The Other ◽  
Growth Mode ◽  
Average Roughness ◽  
Cu Substrate ◽  
Cu Films ◽  
Growth Modes ◽  
Spherical Grains

Abstract The effect of the Cu-target pad roughness on the growth mode of electroless Cu from two different Cu baths was investigated. Bath A having a cyanide based-, and bath B a non-cyanide based stabilizer system. Both baths are commonly used in the PCB-industry. In case of bath B two growth modes are observed for an average roughness higher than Ra=300 nm of the target pad. One mode is a copying of the subjacent Cu-substrate morphology, while the other mode forms spherical grains (Cu-nodules) mostly at the exposed sites of the substrate crystals. These Cu-nodules have typically a radius comparable to the plated electroless Cu thickness and contain a high density of nano voids at the base of these features. The related void formation seems relevant to weaken the overall Cu/Cu/Cu-interconnection in the blind micro via. Interestingly, the tendency to form nodules with increasing Cu-base roughness is widely suppressed for the cyanide based bath A, where the deposit is nodule free up to a target pad roughness of Ra=1000 nm.

The Effect of Cu Target Pad Roughness on the Growth Mode and Void Formation in Electroless Cu Films

2019 ◽  
Author(s):  
Tobias Bernhard ◽  
Sebastian Zarwell ◽  
Edith Steinhauser ◽  
Stefan Kempa ◽  
Frank Bruning
Keyword(s):  
Void Formation ◽  
Growth Mode ◽  
Cu Films

العلاقة التبادلية بين سعر الصرف وأسعار الأسهم دراسة تطبيقية في سوق اسطنبول للأوراق المالية للمدة 2005-2020

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
سعدالله ألنعيمي
Keyword(s):  
Exchange Rate ◽  
Stock Prices ◽  
Negative Impact ◽  
Reciprocal Relationship ◽  
Nominal Exchange Rate ◽  
Share Price ◽  
Theoretical Interpretation ◽  
Short Term ◽  
The Exchange Rate

The study aims to analyzing the reciprocal relationship between the nominal exchange rate of the Turkish lira versus the U.S. dollar and the stock prices of the companies listed on the Istanbul Stock Exchange (ISE) expressed in the general market index for the period from 2005 to 2020 with 192 monthly observations, based on the traditional theory and the theory of portfolio balance model in theoretical interpretation for that relationship, aiming to identify the effect of the exchange rate on stock prices, as well as to analyze the causal relationship between those variables and to identify which of them is the cause or which is the result, using the Autoregressive Distributed Lag (ARDL) model. The research found that the exchange rate has a positive effect on stock prices in the long term, despite the emergence of the negative impact in the short term, but the long-term relationship has corrected the course of the short-term relationship with a time period not exceeding one month, in addition to proving that this relationship takes one direction. From the exchange rate towards stock prices, that is, the exchange rate is the reason and stock prices are the result, therefore the results of this research helps investors to predict future trends of stock prices depending on the exchange rate changes, and it also enables the companies, especially those with foreign transactions, to manage price risks the exchange rate in order to avoid its negative impact on its share price, as it represents an obstacle to achieving its main goal of maximizing the share price

scholarly journals VECTOR AUTOREGRESSIVE APPROACH AFTER FIRST DIFFERENCING: A TIME SERIES ANALYSIS OF INFLATION AND ITS DETERMINANTS IN TANZANIA

2021 ◽  
pp. 43-56
Author(s):  
Rachel R. Cheti ◽  
Bahati Ilembo
Keyword(s):  
Time Series ◽  
Exchange Rate ◽  
Gross Domestic Product ◽  
Money Supply ◽  
Inflation Rate ◽  
Negative Impact ◽  
Causal Effect ◽  
Domestic Product ◽  
Series Data ◽  
Vector Autoregressive

The objective of the study was to examine the trend of inflation and its key determinants in Tanzania. We used secondary time series data observed annually from January 1970 to 2020 which are inflation rate, GDP, Exchange rate and money supply. The vector autoregressive (VAR) model was employed for modeling. Augmented Dickey-Fuller test (ADF) found that inflation rate, Gross Domestic Product (GDP), exchange rate and Money supply (M3) were initially non-stationary but they became stationary after first differencing so as to proceed with the analysis. Preliminary tests before obtaining vector auto regressive model were carried out before determining the relationship between the variables. Diagnostic test such as serial correlation, heteroscedasticity, stability and normality were also important to evaluate the model assumptions and investigate whether or not there are observations with a large, undue influence on the analysis. We used Granger causality test (GCT) to determine causal- effect relationship between the variables. The results show that, there is a long run relationship between the variables, also the results showed that exchange rate and money supply (M3) both have a positive impact on inflation rate while gross domestic product (GDP) revealed a negative impact on inflation rate. Finally, the forecast of inflation rate for 15 years ahead was performed. The study recommends that the government should pursue both contractionary monetary policy and fiscal policy in order to control inflation in the country.

scholarly journals THE IMPACT OF EXCHANGE RATE VOLATILITY ON ECONOMIC GROWTH IN NIGERIA: A DYNAMIC ECONOMETRIC APPROACH

2021 ◽  
pp. 16-40
Author(s):  
Comfort Akinwolere Bukola ◽  
Keyword(s):  
Economic Growth ◽  
Exchange Rate ◽  
Time Series Data ◽  
Negative Impact ◽  
Positive Impact ◽  
Exchange Rate Volatility ◽  
Series Data ◽  
Balance Of Trade ◽  
Econometric Approach ◽  
The Impact

This study examined the impact of exchange rate volatility on economic growth in Nigeria. The study covers the period of 1986 to 2019. Using time series data, the methodology adopted is the Vector Error Correction Mechanism to explore the impact of exchange rate volatility on the selected macroeconomic variables. The result indicated that exchange rate volatility has a significant impact on economic growth, specifically it has a positive impact on inflation, unemployment and balance of trade. On the other hand it has a negative impact on economic growth and investment. The recommendations made include; that relevant authorities should try to avoid systematic currency devaluations in order to maintain exchange rate volatility at a rate that allows adjustment of the balance of payments.

Temperature Dependence of Surface Morphology of Silicon Grown on CaF2/Si by Electron Beam Assisted Mbe

1994 ◽  
Vol 367 ◽  
Author(s):  
P.O. Pettersson ◽  
R.J. Miles ◽  
T.C. Mcgill
Keyword(s):  
Surface Roughness ◽  
Electron Beam ◽  
Photoelectron Spectroscopy ◽  
Silicon Layer ◽  
Surface Damage ◽  
Low Energy ◽  
Growth Mode ◽  
Optimal Range ◽  
Low Energy Electrons ◽  
Ordered Array

AbstractWe present the results of electron beam assisted molecular beam epitaxy (EB-MBE) on the growth mode of silicon on CaF2/Si(111). By irradiating the CaF2 surface with low energy electrons, the fluorine is desorbed, leaving an ordered array of F-centers behind. Using atomic force microscopy (AFM), we do not detect any surface damage on the CaF2 layer due to the low energy electron irradiation. The surface free energy of the CaF2 is raised due to the F-center array and the subsequent silicon layer is smoother. Using AFM and X-ray photoelectron spectroscopy (XPS), we find an optimal range of exposures for high temperature (650°C) growth of the silicon overlayer that minimizes surface roughness of the silicon overlayer and we present a simple model based on geometrical thermodynamics to explain this.We observed a similar optimal range of exposures that minimizes the surface roughness for medium (575°C) and low (500°C) growth temperatures of the silicon layer. We present an explanation for this growth mode based on kinetics.

The Effect of Covid-19, Rupiah Exchange Rate, and Inflation on the Indonesia Sharia Stock Index during the Covid-19 Pandemic

2021 ◽  
Vol 4 (1) ◽  
pp. 313-336
Author(s):  
Achmad Agus Priyono ◽  
Ari Kartiko
Keyword(s):  
Exchange Rate ◽  
Time Series Data ◽  
Negative Impact ◽  
Stock Index ◽  
Series Data ◽  
Stock Market Index ◽  
Short Term ◽  
The Us ◽  
Us Dollar

Purpose of this study is to clarify the effect of the number of daily cases reported to have contracted the Covid-19 virus, the exchange rate of the rupiah against the US dollar and inflation on the movement of the Indonesian Sharia stock index (ISSI) during the Pandemic Covid 19 in the short term and long term. Data analysis methods that used is analysis Error Correction Mechanism (ECM) using Eviews software 10. The data collected is daily time series data starting from March 2, 2020 to May 31, 2021 so that the number of samples collected obtained as many as 283 samples . The results of the study stated that the addition of the daily number of reported cases of contracting the Covid-19 virus has a negative impact on The Indonesian Sharia Stock Market Index (ISSI) during the Covid-19 pandemic, so that encourage the weakening of the Stock Index both in the long and long term short. Likewise, the weakening of the rupiah against the US dollar will caused the fall of the sharia index during the Covid 19 pandemic, both in the long term and long and short term. However, the study found no effect inflation on the Indonesian Sharia Stock Index (ISSI) during the Covid19 pandemic, good long term and short term

Suppression of Kirkendall voiding in Sn-3.5Ag/Cu solder joints by pre-annealing process

2011 ◽  
Vol 2011 (1) ◽  
pp. 000337-000340
Author(s):  
S. H. Kim ◽  
Jin Yu
Keyword(s):  
Solder Joints ◽  
Void Formation ◽  
Annealing Process ◽  
Schematic Diagram ◽  
Cu Films ◽  
Joint Reliability ◽  
Organic Impurities ◽  
Solder Reflow ◽  
Kirkendall Voids ◽  
Annealing Method

In this study, electroplated Cu films were pre-annealed at T (T = 673, 773, 873 K) for varying times. Sn-3.5Ag solder reflowed over the Cu films and subsequently aged at 150°C for 240 hrs. Effects of pre-annealing on the microstructure of Cu films, as well as contents of organic impurities incorporated in the Cu films were investigated. After solder reflow, the formation of Kirkendall voids at Cu3Sn/Cu interface was observed from SEM micrographs. Results show that the pre-annealing process significantly suppressed Kirkendall void formation in the Sn-3.5Ag/Cu solder joints. A line fraction of voids at the Cu3Sn/Cu interface was definitely suppressed in the case of 500°C and 600°C pre-annealed samples compared to as-deposited Cu sample. SIMS analyses revealed that pre-annealing reduced the level of impurities in the Cu films, especially S and C. The mechanism of suppressing Kirkendall voids at the Cu3Sn/Cu interface was presented by schematic diagram, and it could be seen that pre-annealing method has a potential to enhance solder joint reliability.

scholarly journals Physiological State, Growth Mode, and Oxidative Stress Play a Role in Cd(II)-Mediated Inhibition of Nitrosomonas europaea 19718

2008 ◽  
Vol 74 (8) ◽  
pp. 2447-2453 ◽  
Author(s):  
Kartik Chandran ◽  
Nancy G. Love
Keyword(s):  
Oxidative Stress ◽  
16S Rrna ◽  
Physiological State ◽  
Membrane Integrity ◽  
Fold Increase ◽  
Nitrosomonas Europaea ◽  
Growth Mode ◽  
Batch Cultures ◽  
Growth Modes ◽  
The Impact

ABSTRACT The goal of this study was to determine the impact of physiological growth states (batch exponential and batch stationary growth) and growth modes (substrate-limited chemostat, substrate-sufficient exponential batch, and substrate-depleted stationary batch growth) on several measures of growth and responses to Cd(II)-mediated inhibition of Nitrosomonas europaea strain 19718. The specific oxygen uptake rate (sOUR) was the most sensitive indicator of inhibition among the different responses analyzed, including total cell abundance, membrane integrity, intracellular 16S rRNA/DNA ratio, and amoA expression. This observation remained true irrespective of the physiological state, the growth mode, or the mode of Cd(II) exposure. Based on the sOUR, a strong time-dependent exacerbation of inhibition (in terms of an inhibition coefficient [Ki ]) in exponential batch cultures was observed. Long-term inhibition levels (based on Ki estimates) in metabolically active chemostat and exponential batch cultures were also especially severe and comparable. In contrast, the inhibition level in stationary-phase cultures was 10-fold lower and invariable with exposure time. Different strategies for surviving substrate limitation (a 10-fold increase in amoA expression) and starvation (the retention of 16S rRNA levels) in N. europaea cultures were observed. amoA expression was most negatively impacted by Cd(II) exposure in the chemostat cultures, was less impacted in exponential batch cultures, and was least impacted in stationary batch cultures. Although the amoA response was consistent with that of the sOUR, the amoA response was not as strong. The intracellular 16S rRNA/DNA ratio, as determined by fluorescence in situ hybridization, also did not uniformly correlate with the sOUR under conditions of inhibition or no inhibition. Finally, Cd(II)-mediated inhibition of N. europaea was attributed partially to oxidative stress.

Controls of Crystallinity and Surface Roughness of Cu Film in Partially Ionized Beam Deposition

1995 ◽  
Vol 396 ◽  
Author(s):  
Seok-Keun Koh ◽  
Ki-Hwan Kim ◽  
Won-Kook Choi ◽  
Hong-Gui Jang ◽  
Young-Soo Yoon ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Ionization Potential ◽  
Relative Intensity ◽  
Intensity Ratio ◽  
Ion Beam ◽  
Average Energy ◽  
Relative Intensity Ratio ◽  
Cu Films ◽  
Acceleration Potential ◽  
Residual Gas

AbstractChanges of crystallinity and surface roughness are discussed in terms of the average energy per deposited atom in the partially ionized beam(PIB) deposition. The average energy per deposited atom can be controlled by adjusting the ionization potential, Vi and acceleration potential, Va. The ion beam consists of a Cu ion beam and residual gas ion beam and residual gases as well as Cu particles that were ionized and accelerated to provide the film with energy required for film-growth. The relative contribution of residual gas ions and Cu ions to total average energy per deposited atom was varied with the ionization potential. At fixed ionization potentials of Vi=400 V and Vi=450 V, the average energy per deposited atom was varied in the range of 0 to 120 eV with acceleration potential Va, of 0 to 4 kV. The relative intensity ratio, 1(111)/I(200), of the Cu films increased from 6 to 37 and the root mean square(Rms) surface roughness decreased with an increase in acceleration potential at Vi=400 V. The relative intensity ratio, I(lll)/I(200), of Cu films increased up to Va=2 kV at Vi=2 kV, above which a decrease occurred, and the surface roughness of Cu films increased as a funtion of acceleration potential. The degree of preferred orientation was closely related with the average energy per deposited atom. The change of Rms roughness might be affected by ion flux, particle energy and preferred orientation.

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