• Title/Summary/Keyword: Single Adhesive Layer

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Appropriate Package Structure to Improve Reliability of IC Pattern in Memory Devices (메모리 반도체 회로 손상의 예방을 위한 패키지 구조 개선에 관한 연구)

  • 이성민
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.32-35
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    • 2002
  • The work focuses on the development of a Cu lead-frame with a single-sided adhesive tape for cost reduction and reliability improvement of LOC (lead on chip) package products, which are widely used for the plastic-encapsulation of memory chips. Most of memory chips are assembled by the LOC packaging process where the top surface of the chip is directly attached to the area of the lead-frame with a double-sided adhesive tape. However, since the lower adhesive layer of the double-sided adhesive tape reveals the disparity in the coefficient of thermal expansion from the silicon chip by more than 20 times, it often causes thermal displacement-induced damage of the IC pattern on the active chip surface during the reliability test. So, in order to solve these problems, in the resent work, the double-sided adhesive tape is replaced by a single-sided adhesive tape. The single-sided adhesive tape does net include the lower adhesive layer but instead, uses adhesive materials, which are filled in clear holes of the base film, just for the attachment of the lead-frame to the top surface of the memory chip. Since thermal expansion of the adhesive materials can be accommodated by the base film, memory product packaged using the lead-flame with the single-sided adhesive tape is shown to have much improved reliability. Author allied this invention to the Korea Patent Office for a patent (4-2000-00097-9).

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AE Characteristics on Microscopic Failure Behavior of Carbon/Epoxy Comosite Prepared by Cocure and Precure Process (Cocure/Precure 경화공정에 의해 제조된 Carbon/Epoxy 복합재료의 미시적 파손거동에 대한 AE 특성)

  • Lee, Jin-Gyeong;Lee, Jun-Hyeon;Lee, Min-Rae;Choe, Heung-Seop
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.10 s.181
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    • pp.2520-2528
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    • 2000
  • Mechanical and physical properties of composite materials make a great difference due to their cure process condition. In order to clarify the effect of cure process condition on the microscopic damage behavior and failure mechanism of Carbon/Epoxy composites, three point bend test has been performed. For this purpose, two kinds of specimens with single adhesive and multiple adhesive layers were prepared. For single adhesive layer, four different types of specimen were used, that is, non-sanding, sanding, cocured, laminated specimens. Three different types of specimen were also used for the multiple adhesive layer, non-sanding, sanding, cocured specimens. Acoustic emission technique has also been employed to monitor the damage progresses associated with each micro-failure mechanism. The characteristics of AE parameters associated with micro-failure mechanism of each specimen were discussed.

EFFECT OF INTERMEDIATE RESIN HYDROPHILICITY ON BOND STRENGTH OF SINGLE STEP ADHESIVE (중간레진의 친수성이 상아질 접착에 미치는 영향)

  • Kim, Yong-Sung;Park, Sang-Hyuk;Choi, Gi-Woon;Choi, Kyoung-Kyu
    • Restorative Dentistry and Endodontics
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    • v.32 no.5
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    • pp.445-458
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    • 2007
  • The purpose of this study was to evaluate the bond strength of a new Single step system with different curing mode composites, and to evaluate the effect of the intermediate resins which have different hydrophilicity on bonding ability by means of the micro shear bond testing and TEM examination for the adhesive interface. The adhesive used in this study was an experimental single step system (Bisco Inc., Schaumburg IL). Experimental groups were produced by using six kinds of intermediate resin having different hydrophilicity that was hydrophilic, hydrophobic and most hydrophobic resin and as filled or not after applying adhesive. Each experimental group was further divided into two subgroups whether the adhesive was light cured or not. Dual cured composite (Bis Core, Bisco Ltd., Schaumburg, IL) was placed on the adhesive layer as light cure or self cure mode. The results or bond strength were statistically analyzed using one way ANOVA and multiple comparisons are made using Tukey's test at ${\alpha}\;<\;0.05$ level. The results of this study were as follows ; 1. The application of intermediate resin did not increase the bond strength for light cured composite. 2. The bond strength of an experimental adhesive with self cured composite was significantly increased by the application of intermediate resin layer. 3. The bond strength of adhesive was irrespective of the cure or not of itself before intermediate resin layer applied. 4. As applied hydrophilic resin layer was, the initial bond strength was higher than both hydrophobic and most hydrophobic one used but there was no significance. Using a single step adhesive with dual/self cured composite, the incompatibility between both of them should be solved by the application of intermediate hydrophobic resin to reduce the adhesive permeability. However, Single step adhesive can be used in the light cured composite restoration without any decrease of the initial bond strength.

Experimental examination for effect of voids on bonding performance in cryogenic temperature condition (내부 기공이 극저온에서 접착강도에 미치는 영향에 대한 실험적 고찰)

  • Shon, Min-Young;Kim, Jong-Ho;Kim, Jong-Hak
    • Composites Research
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    • v.22 no.2
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    • pp.14-17
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    • 2009
  • Adhesive joints are widely used for structural joining applications in various fields and environmental conditions. Polyurethane adhesive is using for LNG carrier with cryogenic temperature condition. In industrial application of polyurethane adhesive, void of adhesive layer is often discussed regarding its effects on bonding properties. In present study, artificial void were prepared on Polyurethane adhesive layer with various size and location. The single lap shear test was carried out by using prepared specimens under $-170^{\circ}C$. As a result, it was confirm that the void of adhesive layer didn't affect the adhesion properties independent of their size and location.

A Study on Strength Evaluation of Adhesive Joints(1st Report, Stress Analysis and Fracture Strength of Adhesive Single-Lap Joint) (접착이음의 강도평가에 관한 연구 (제1보 겹치기 접착이음의 응력해석과 파괴강도))

  • 정남용
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.4
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    • pp.667-674
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    • 1992
  • Recently advantages in composite and light weight material technique have led to the increased use of structural adhesives in various industries. In spite of such wide application of the adhesive joints, the evaluation method of fracture strength and design methodology of them, have not been established. In this study finite element method, theoretical and experimental analyses were investigated according to changes of lap length and adhesive for adhesive single-lap joint. As the results, the strength evaluation of adhesive joint by conventional nominal stress, was pointed out inadequate strength evaluation and design method regardless stress singularity, stress distribution and crack propagation in its adhesive layer. Also, it was examined the problems to apply fracture mechanics by means of static and fatigue test.

Stress Analysis Of Wavy Lap Joint (WAVY LAP JOINT 응력 해석)

  • 김위대;양승희
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.11a
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    • pp.216-219
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    • 2000
  • The adhesive bonded single-lap joint is due to its intrinsic load eccentricity problem, severe peel stresses concentration occur at both end of the joint. In this paper, new lap-joint is designed to avoid the singular peel stress, and to compare the stresses of the middle adhesive layer between the single-lap joint and the wavy-lap joint. Two adherend lay-up, i.e., [90/0/90/0]$_{2s}$ and [0/90/0/90]$_{2s}$ were consider in the study.

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Failure Mode and Strength of Unidirectional Composite Single Lap Bonded Joints I. Experiments (일방향 복합재료 Single Lap접합 조인트의 파손 모드 및 강도 I. 실험)

  • Kim Kwang-Soo;Yoo Jae-Seok;An Jae-Mo;Jang Young-Soon
    • Composites Research
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    • v.17 no.6
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    • pp.14-21
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    • 2004
  • Failure process, mode and strength of unidirectional composite single lap bonded joints were investigated experimentally with respect to bonding methods, those are, co-curing with and without adhesive and secondary bonding. The co-cured joint specimens without adhesive had the largest failure strength. Progressive failures along the adhesive layer occurred in the secondary bonded specimens. In the co-cured specimens with adhesive film which had better material strength and adhesion performance, delamination failure occurred and the joint strengths were less than those of secondary bonded specimens. Delamination failure did not occur in the secondary bonded specimens because of earlier crack growth and progressive failure in the adhesive layer. Therefore, failure strength of composite bonded Joints were not always proportionate to material strength and adhesion performance of the adhesive due to the weakness of delamination in composite materials. The effects of surface roughness, bondline thickness and fillets were also studied on secondary bonded specimens.

Effect of Spew Fillet on Failure Strength Properties of Natural Fiber Reinforced Composites Including Adhesive Bonded Joints (접착제 접합된 자연섬유강화 복합재료의 파괴강도 특성에 미치는 접착제 필릿의 영향)

  • Yoon Ho-Chel;Choi Jun-Yong;Kim Yong-Jig;Lim Jae-Kyoo
    • Journal of Welding and Joining
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    • v.23 no.6
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    • pp.67-71
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    • 2005
  • This paper is concerned with a study on fracture strength of composites in an adhesive single lap joint. The tests were carried out on joint specimens made with hybrid stacked composites consisting of the polyester and bamboo natural fiber layer. The main objective of this work was to evaluate the fracture properties adjacent to adhesive bonded joint of natural fiber reinforced composite specimens. From the results, natural fiber reinforced composites have lower tensile strength than the original polyester. But tensile-shear strength of natural fiber reinforced composites with bamboo layer far from adhesive bond is as high as that of the original polyester adhesive bonded joints. Spew filet at the end of the overlap reduced the stress concentration at the bonded area. Spew fillet and position of bamboo natural fiber layer have a peat effect on the tensile-shear strength of natural fiber reinforced composites including adhesive bonded joints.

Application of Single Lap-Shear Test for Extracting Adhesive Bonding Strength of Coating Layer on Galvannealed sheet (합금화용융아연코팅강판의 코팅층 접합강도 평가를 위한 단일 겹치기이음 시험의 적용)

  • Lee, Jung-Min;Lee, Cha-Joo;Lee, Sang-Gon;Ko, Dae-Cheol;Kim, Byung-Min
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.238-243
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    • 2007
  • This paper is designed to estimate the adhesion strength of coating layer on galvannealed steel sheet using lap shear test. The single lap shear test is the most commonly used standard test for determining the strength of medium-strength and high strength bonds. The bond strength of bonded single lap joints on subjecting the substrates to loads is determined by lap shear forces in the direction of the bonded joint. In this study, specimen for adhesion strength test was made to attach coated sheet to cold rolled sheet and were heated in temperature of 180 for 20minutes. After test, detached parts of coatings on coated sheet were observed using SEM and EDX to identify substrate and complete detachment. The tested results showed that adhesive strength of coating is unrelated to anisotropy of sheet and is difficult to be extracted using conventional theory because of fine cracks of coating layers which were created during annealing process.

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