• Title, Summary, Keyword: Warpage

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Warpage Analysis for Top and Bottom Packages of Package-on-Package Processed with Thin Substrates (박형 기판을 사용한 Package-on-Package용 상부 패키지와 하부 패키지의 Warpage 분석)

  • Park, D.H.;Shin, S.J.;Ahn, S.G.;Oh, T.S.
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.2
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    • pp.61-68
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    • 2015
  • Warpage analysis has been performed for top and bottom packages of thin package-on-packages processed with different epoxy molding compounds (EMCs). Warpage deviation was measured for packages molded with the same EMCs and also the warpage deviations of top and bottom substrates themselves were characterized in order to identify the major factor causing the package warpage. For the top and bottom packages processed with thin substrates, the warpage deviation of the substrates was large, which made it difficult to figure out the effect of EMC properties on the package warpage. Top packages, where the molding area of $13mm{\times}13mm$ covered the most of the substrate area ($14mm{\times}14mm$), exhibited similar warpage behavior with changing the temperature. On the other hand, bottom packages, where the molding area was only $8mm{\times}8mm$, exhibited the complex warpage behavior due to simultaneous occurrence of (+) and (-) warpages on the same package. Accordingly, the bottom packages showed dissimilar temperature-warpage behavior even being processed with the same EMCs.

Study on Design Parameters of Substrate for PoP to Reduce Warpage Using Finite Element Method (PoP용 Substrate의 Warpage 감소를 위해 유한요소법을 이용한 설계 파라메타 연구)

  • Cho, Seunghyun;Lee, Sangsoo
    • Journal of the Microelectronics and Packaging Society
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    • v.27 no.3
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    • pp.61-67
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    • 2020
  • In this paper, we calculated the warpage of bare substrates and chip attached substrates by using FEM (Finite Element Method), and compared and analyzed the effect of the chips' attachment on warpage. Also, the effects of layer thickness of substrates for reducing warpage were analyzed and the conditions of layer thickness were analyzed by signal-to-noise ratio of Taguchi method. According to the analysis results, the direction of warpage pattern in substrates can change when chips are attached. Also, the warpage decreases as the difference in the CTE (coefficient of thermal expansion) between the top and bottom of the package decreases and the stiffness of the package increases after chips are loaded. In addition, according to the impact analysis of design parameters on substrates where chips are not attached, in order to reduce warpage, the inner layers of the circuit layer Cu1 and Cu4 has be controlled first, and then concentrated on the thickness of the solder resist on the bottom side and the thickness of the prepreg layer between Cu1 and Cu2.

A study on the warpage in injection molded part for various rib design (사출성형품의 리브 설계에 따른 휨의 연구)

  • Lee, Min;Lyu, Min-Young
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.2 no.4
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    • pp.54-61
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    • 2008
  • Warpage, which is one of the molding trouble, acts as possible factor which results in defect in assembly. In this study, a mold was designed to produce specimens with rib parallel to flow direction, specimens with rib perpendicular to flow direction and specimens without rib. This work researched change of warpage according to injection molding condition such as injection pressure, packing pressure, packing time, resin temperature, mold temperature in non-crystalline resins(PC, ABS), crystalline resins(PP, PA66), and 30% glass fiber reinforced-resins(PC, ABS, PP, PA66).Specimens with rib and Crystalline resins show more warpage than specimens without rib and non-crystalline resins, respectively. Glass fiber reinforced-resins and specimens with rib parallel to flow direction show smaller warpage than conventional resins and specimens with rib perpendicular to flow, respectively. Specimens with rib and specimens without rib show reduced warpage as packing time increases. In addition, warpage increase as resin temperature increases. It is found that CAE shows similar tendency with experiment as packing time, resin temperature. when the rib is caused, warpage will reduce and prevent the transformation. product of a irregular form occurs warpage. In the study It'll be basic data that product occurs warpage, preferablity.

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Warpage Characteristics Analysis for Top Packages of Thin Package-on-Packages with Progress of Their Process Steps (공정 단계에 따른 박형 Package-on-Package 상부 패키지의 Warpage 특성 분석)

  • Park, D.H.;Jung, D.M.;Oh, T.S.
    • Journal of the Microelectronics and Packaging Society
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    • v.21 no.2
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    • pp.65-70
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    • 2014
  • Warpage of top packages to form thin package-on-packages was measured with progress of their process steps such as PCB substrate itself, chip bonding, and epoxy molding. The $100{\mu}m$-thick PCB substrate exhibited a warpage of $136{\sim}214{\mu}m$. The specimen formed by mounting a $40{\mu}m$-thick Si chip to such a PCB using a die attach film exhibited the warpage of $89{\sim}194{\mu}m$, which was similar to that of the PCB itself. On the other hand, the specimen fabricated by flip chip bonding of a $40{\mu}m$-thick chip to such a PCB possessed the warpage of $-199{\sim}691{\mu}m$, which was significantly different from the warpage of the PCB. After epoxy molding, the specimens processed by die attach bonding and flip chip bonding exhibited warpages of $-79{\sim}202{\mu}m$ and $-117{\sim}159{\mu}m$, respectively.

A Reliability and warpage of wafer level bonding for CIS device using polymer (폴리머를 이용한 CIS(CMOS Image Sensor) 디바이스용 웨이퍼 레벨 접합의 warpage와 신뢰성)

  • Park, Jae-Hyun;Koo, Young-Mo;Kim, Eun-Kyung;Kim, Gu-Sung
    • Journal of the Microelectronics and Packaging Society
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    • v.16 no.1
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    • pp.27-31
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    • 2009
  • In this paper, the polymer adhesive bonding technology using wafer-level technology was investigated and warpage results were analyzed. Si and glass wafer was bonded after adhesive polymer layer and dam pattern for uniform state was patterned on glass wafer. In this study, warpage result decreased as the low of bonding temperature of Si wafer, bonding pressure and height of adhesive bonding layer. The availability of adhesive polymer bonding was confirmed by TC, HTC, Humidity soak test after dicing. The result is that defect has not found without reference to warpage.

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Optimal Design of Dummy Patterns for Minimizing PCB Warpage (PCB 휨의 최소를 위한 더미 패턴의 최적 설계)

  • Lee, Sang-Hyuk;Kim, Sun-Kyoung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.6
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    • pp.577-583
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    • 2009
  • In this work, a design method that minimizes PCB warpage is proposed. This work suggests that narrow dummy patterns are placed on the discetized location along the periphery of the PCB to control the warpage. The warpage is numerically simulated base on direct modeling of PCB patterns. The optimal pattern that minimizes warpage is determined using the human-based genetic algorithm.

Study on the Nonlinear Characteristic Effects of Dielectric on Warpage of Flip Chip BGA Substrate

  • Cho, Seunghyun
    • Journal of the Microelectronics and Packaging Society
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    • v.20 no.2
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    • pp.33-38
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    • 2013
  • In this study, both a finite element analysis and an experimental analysis are executed to investigate the mechanical characteristics of dielectric material effects on warpage. Also, viscoelastic material properties are measured by DMA and are considered in warpage simulation. A finite element analysis is done by using both thermal elastic analysis and a thermo-viscoelastic analysis to predict the nonlinear effects. For experimental study, specimens warpage of non-symmetric structure with body size of $22.5{\times}22.5$ mm, $37.5{\times}37.5$ mm and $42.5{\times}42.5$ mm are measured under the reflow temperature condition. From the analysis results, experimental warpage is not similar to FEA results using thermal elastic analysis but similar to FEA results using thermo-viscoelastic analysis. Also, its effect on substrate warpage is increased as core thickness is decreased and body size is getting larger. These FEA and the experimental results show that the nonlinear characteristics of dielectric material play an important role on substrate warpage. Therefore, it is strongly recommended that non-linear behavior characteristics of a dielectric material should be considered to control warpage of FCBGA substrate under conditions of geometry, structure and manufacturing process and so on.

A Study on Manufacturing of Plastic Injection Mold for Warpage Characteristics of Mobile Phone Cover (모바일폰 커버의 휨특성 평가를 위한 금형 제작에 관한 연구)

  • Kim M. Y.;Lee S. H.;Kwon C. O.;Kim O. R.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.126-131
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    • 2005
  • In the present study, warpage characteristics of mobile phone cover through injection molding process were investigated by using design of experiments. Warpage in plastic injection molding process has a significant effect on quality of product. Effects of injection time, packing pressure, packing time, mold temperature ana melt temperature on warpage of mobile phone cover were considered by CAE analysis and experiment with Taguchi method. The degree of warpage for the injection molded product was measured by using three dimensional CMM. It was shown that temperature parameter has more significant effect on the warpage of mobile phone cover than pressure parameter.

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Design of Gate Locations, Molding Conditions, and Part Structure to Reduce the Warpage of Short-Fiber Reinforced Injection Molded Part (단섬유 보강 사출성형품의 휨 감소를 위한 게이트 위치, 성형 조건 및 제품 구조 설계)

  • Choi, D.S.
    • Transactions of Materials Processing
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    • v.17 no.6
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    • pp.443-448
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    • 2008
  • Fiber reinforced injection molded parts are widely used in recent years because of their improved properties of materials such as specific stiffness, specific strength, and specific toughness. The demand for products with high precision is increasing and it is important to minimize the warpage of the products. The warpage of short-fiber reinforced product is caused by anisotropy induced by fiber orientation as well as the residual stresses induced during the molding process. In order to reduce the warpage of the part, it is important to achieve successful mold design, processing control, and part design. In the present study, the design of gating system, molding condition, and part structure were carried out and verified with numerical analysis using a commercial CAE code Moldflow. The numbers and locations of gates were iteratively determined, and the molding conditions which can decrease the warpage of the part were investigated. Finally, slight structural modification of the part was conducted to reduce the locally concentrated warpage.

A Study on Plastic Injection Molding for Warpage Characteristics Evaluation of Mobile Phone Cover (모바일폰 커버의 휨특성 평가를 위한 사출 성형에 관한 연구)

  • Kim O. R.;Kim M. Y.;Lee S. H.;Kwon C. O.
    • Transactions of Materials Processing
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    • v.15 no.1
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    • pp.76-81
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    • 2006
  • In this study, warpage characteristics of mobile phone cover through injection molding process were investigated using design of experiments in injection molding process. Warpage in plastic injection molding has a significant effect on quality of product. Effects of injection time, packing pressure, packing time, mold temperature and melt temperature on the warpage of mobile phone cover were considered by numerical analysis and experiment with Taguchi method. The degree of warpage for the injection molded part was measured by using three dimensional coordinate measurement machine. It was shown that temperature control factor has more significant effect on the warpage of mobile phone cover than pressure control factor.