MODEL ANALYZING FOR REUSING GOLD WIRE CAPILLARY IN THE GOLD WIRE BONDING PROCESS

Manufacturing process improvement is necessary for manufacturers to gain business advantages. Re-using or increasing the useful lives of machine parts is considered to be a process of performance improvement. To re-use parts, the manufacturers must know the effects of the factors related to workpieces' qualities to prevent defects. This research study aims at presenting the results of analysing the effects of the factors and mathematical models for bond shear strength when reusing gold wire bonding capillary in the gold wire bonding process of integrated circuit (IC) products using design experiment. The operation factors in the reference experiment, including bond force, bond time, USG current, EFO current and EFO gap, are investigated. The Fractional Factorial Design was used to determine five factors that affect the bond shear strength. The analysis of the results show that the bond force is a significant factor where increasing bond force factors leads to increasing bond shear strength. In the end, a Regression model of bond shear strength is obtained to show the result between the bond shear strength and effect of factors. ABSTRAK: Proses pembaharuan pengilangan adalah penting untuk para pengilang bagi memperoleh keuntungan bisnes. Guna-semula atau menambah jangka hayat pada bahagian-bahagian tertentu pada mesin adalah dianggar sebahagian proses penambahbaikan prestasi mesin. Bagi mengguna semula bahagian-bahagian ini, pengilang mesti mengetahui akibat sesuatu faktor berkaitan kualiti bahan bagi mengelak kecacatan. Kajian ini bertujuan menyampaikan dapatan kajian melalui kesan faktor dan model matematik pada kekuatan ricihan ikatan apabila mengguna semula wayar emas melalui proses kapilari ikatan wayar emas pada produk litar bersepadu melalui rekaan eksperimen. Faktor operasi melalui rujukan eksperimen dari daya ikatan, masa ikatan, arus USG, arus EFO dan jarak EFO dikaji. Rekaan Faktorial Pecahan digunakan bagi mendapatkan lima faktor yang mempengaruhi kekuatan ricihan ikatan. Dapatan kajian menunjukkan daya ikatan merupakan faktor penting di mana, pertambahan faktor daya ikatan menguatkan ricihan ikatan. Akhirnya, model Regression kekuatan ricihan ikatan diperoleh bagi menjelaskan dapatan kajian antara kekuatan ricihan ikatan dan kesan faktor.

Development and Performance Evaluation of a High-Permeability and High-Bonding Fog-Sealing Adhesive Material

Herein, the effects of the contents of emulsified asphalt, waterborne epoxy resin emulsion, and curing agent on the permeability, bond shear strength, water stability, and aging resistance of epoxy-emulsified asphalt were studied. A formulation of epoxy-emulsified asphalt as a fog-sealing adhesive material was recommended, and a comparison between the fabricated adhesive material and a traditional Chinese fog-sealing adhesive material was conducted to verify the technical performance of the new material. In addition, the strength formation mechanism of the epoxy-emulsified asphalt was revealed via microcosmic analysis. Results show that the curing agent content mainly affects the permeability of epoxy-emulsified asphalt, and the emulsified asphalt content significantly affects the bond shear strength, water stability, and aging resistance. Moreover, the ratio of waterborne epoxy resin emulsion to the curing agent (epoxy ratio) has a certain effect on the bond shear strength. In the recommended formulation (a high-permeability and high-bonding fog-sealing adhesive material, which can be referred to simply as HPBFA), emulsified asphalt accounts for 80% of the total mass of the mixture, and the epoxy ratio is 2:1–3:1. It can improve air permeability, bond shear strength, water stability and aging resistance. The HPBFA-cured material exhibits a continuous three-dimensional network structure, hydrophobic surface, and large contact angle. Furthermore, the initial thermal weight loss temperature of the HPBFA-cured material is significantly higher than the environmental aging temperature. Additionally, the maximum temperature decomposition range is 0–160 °C, indicating improved strength, wear resistance, permeability, and aging resistance of the material.

Assessing the Moisture Susceptibility at Interface of Asphalt Concrete Pavement Layers

The asphalt concrete flexible pavement consists of many layers interconnected by tack coat binder. The resistance of the bonding tack coat to the impact of moisture that ingress through the cracks into the interface of asphalt concrete can cause premature matrix degradation of pavement structure. In this investigation, the influence of moisture susceptibility on the bond strength and horizontal deformation of three layers of asphalt concrete are assessed under repeated shear stresses. The suitability of two types of tack coat (Rapid curing cutback RC-70 and medium setting cationic emulsion CMS) to support the resistance to moisture damage have been investigated. Asphalt concrete slab specimens have been prepared with the aid of roller compactor for the typical three layers usually implemented in flexible pavement in Iraq (wearing, binder and asphalt stabilized base courses) with (12, 19.5 and 25) mm nominal maximum size of aggregate. Layers were bonded by tack coat after construction of the bottom layers. Core specimens have been obtained and subjected to moisture damage then practiced 1200 cyclic shear stresses in the Pneumatic Repeated Load System PRLS using a special manufactured mold. Control core specimens have been obtained and practiced 1200 cyclic shear stresses. Specimens were tested for bond shear strength. The bond shear strength and horizontal deformation under repeated shear stresses were analyzed and compared. It was concluded that the horizontal permanent deformation increases by a range of (4 -27) % and (2-57) % after moisture damage when RC-70 and CMS tack coat were implemented respectively at various application rates. However, the reduction in bond shear strength due to moisture damage ranges between (2-17) % and (5 -30) % for RC-70 and CMS Tack coat interfaces. CMS tack coat exhibits higher bond shear strength ratio BSSR than RC-70 tack coat for all the application rates and is recommended for use from the moisture susceptibility point of view. Keywords: Moisture Susceptibility; Interface; Asphalt Concrete; Bond Shear; Horizontal Deformation; Tack Coat;

Analytically Determining Bond Shear Strength of Fully Grouted Rock Bolt Based on Pullout Test Results

Usually, in a fully grouted rock bolt pullout test the load-displacement curve of the rock bolt head is recorded. This paper presents an analytical method to use this curve for determining the bond (bolt-grout and grout-rock interface) shear strength parameters. For this purpose, the fully grouted rock bolt interaction with grout and surrounding rock in the pullout test is investigated and the load-displacement curve of the bolt head (beginning of the bonded section) is obtained analytically. For modeling the bolt-grout interface behavior a distribution of the shear stress along the fully grouted rock bolt by consideration of bolt shank failure is used. In this regard, different stages including complete bonding, partial decoupling, decoupling with the residual shear strength and complete decoupling are considered. With increasing the applied load, two possible cases involving the rock bolt complete pullout and bolt shank yielding are taken into account. Based on the presented analytical method, the obtained bolt head load-displacement curve can be compared with the one recorded in the pullout test. With this, the relevance of selected shear strength parameters compared to real parameters can be assessed. A flowchart for determining the bolt bond shear strength parameters is presented using the trial and error method (coded in Matlab). The proposed solution is used to determine two experimental pullout shear strength parameters. The results show good agreement between predicted and calculated load-displacement curves.

Wettability and Bond Shear Strength of Sn-9Zn Lead-Free Solder Alloy Reflowed on Copper Substrate

Lead-free solders are environment friendly and are in great demand for microelectronic applications. In the present study, Sn-9Zn lead free solder alloy was solidified on Cu substrate for different reflow times from 10 to 1000s. The influence of reflow time on wetting, formation of intermetallic compounds (IMCs) and bond shear strength was studied using dynamic contact angle analyzer, bond tester and scanning electron microscopy. The results indicate that, the wettability of the solder alloy increased with increase in reflow time. Microstructure study revealed the presence of Cu5Zn8 and CuZn5 IMCs at the interface. The thickness of an IMC increased with increase in the reflow time. The mean thickness of about 11μm for Cu5Zn8 IMC layer was observed for the reflow time of 1000s. The thickness of CuZn5 layer increased up to a reflow time of 100s and decreases thereafter. The bond shear strength increased up to 100s and decreased with increase in reflow time. The decrement in shear strength at higher reflow time is mainly due to excessive thickness of Cu5Zn8 IMC layer and diffusion of Sn from bulk solder towards the substrate. The excessive thick IMC layer exhibited pre micro-cracks led to the brittle failure of bond under the influence of shear stress.