• 대한기계학회논문집A
• /
• 제24권8호
• /
• pp.1968-1799
• /
• 2000

A warpage analysis program has been developed for fiber-reinforced injection molded parts. The warpage is predicted from the residual stress and anisotropic thermo-mechanical properties coupled with fiber orientation in the integrated injection molding simulation. A simple elastic model is used for the calculation of thermally and pressure-induced residual stresses which are employed as the initial conditions in the structural analysis. To improve the reliability of warpage analysis, a new triangular flat shell element superimposing well-known efficient plate bending and membrane element is presented. The numerical examples address the necessity to use anisotropic models for fiber-reinforced materials and show that predicted warpage is in good agreement with experimentally measured one.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집A
• /
• pp.745-750
• /
• 2000

A warpage analysis program has been developed for fiber-reinforced injection molded parts. The warpage is Predicted from the residual stress and anisotropic thermo-mechanical properties coupled with fiber orientation in the integrated injection molding simulation. A simple elastic model is used for the calculation of thermally and pressure-induced residual stresses which are employed as the initial conditions in the structural analysis. To improve the reliability of warpage analysis, a new triangular flat shell element superimposing well-known efficient plate bending and membrane element is presented. The numerical examples address the neccesity to use anisotropic models for fiber-reinforced materials and show that predicted warpage is in good agreement with experimentally measured one.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2011년도 춘계학술대회 논문집
• /
• pp.735-736
• /
• 2011

• 반도체디스플레이기술학회지
• /
• 제17권4호
• /
• pp.42-45
• /
• 2018

As The semiconductor decrease from 10 nanometer to 7 nanometer, It is suggested that "More than Moore" is needed to follow Moore's Law, which has been a guide for the semiconductor industry. Fan-Out Wafer Level Package(FOWLP) is considered as the key to "More than Moore" to lead the next generation in semiconductors, and the reasons are as follows. the fan-out WLP does not require a substrate, unlike conventional wire bonding and flip-chip bonding packages. As a result, the thickness of the package reduces, and the interconnection becomes shorter. It is easy to increase the number of I / Os and apply it to the multi-layered 3D package. However, FOWLP has many issues that need to be resolved in order for mass production to become feasible. One of the most critical problem is the warpage problem in a process. Due to the nature of the FOWLP structure, the RDL is wired to multiple layers. The warpage problem arises when a new RDL layer is created. It occurs because the solder ball reflow process is exposed to high temperatures for long periods of time, which may cause cracks inside the package. For this reason, we have studied warpage in the FOWLP structure using commercial simulation software through the implementation of the reflow process. Simulation was performed to reproduce the experiment of products of molding compound company. Young's modulus and poisson's ratio were found to be influenced by the order of influence of the factors affecting the distortion. We confirmed that the lower young's modulus and poisson's ratio, the lower warpage.

• 한국기계가공학회지
• /
• 제8권3호
• /
• pp.90-97
• /
• 2009

In the study, a design methodology for robust minimization of a warpage in injection-molded part is presented. Taguchi's parameter design method is integrated with a computer simulation tool for injection molding to search for best design with robustness against the process variability by noises. The proposed methodology is based on a two-stage process: (1) reducing a warpage in the part by optimizing the part geometry including the layout and size of ribs, and (2) additionally minimizing the warpage by optimizing process conditions. An example is used to illustrate the usefulness of the design methodology.

• 마이크로전자및패키징학회지
• /
• 제25권4호
• /
• pp.41-45
• /
• 2018

패널 레벨 패키지(Panel Level Package)에서 공정 단계별로 발생하는 휨(warpage)에 대해 유한요소법을 이용하여 전산모사를 진행하였다. $5{\times}5mm^2$ 크기의 실리콘 칩이 총 221개가 포함된 $122.4{\times}93.6mm^2$ 크기의 패널에 대해서 (1) EMC 몰딩, (2) detach core 부착, (3) 가열, (4) 캐리어 분리, (5) 냉각의 5 단계에 대해서 해석을 수행하였으며, 캐리어와 detach core 소재로 유리와 FR4의 조합이 휨 현상에 미치는 영향을 조사하였다. 캐리어 및 detach core의 소재에 따라 공정 단계별로 휨의 경향이 다르게 나타나고 있으나, 최종적으로는 유리를 캐리어로 사용하는 경우에 detach core의 소재와 관계없이 FR4 캐리어에 비해 낮은 휨 값을 나타내었으며 유리 캐리어와 유리 detach core의 조합에서 가장 낮은 휨 값이 관찰되었다.

• 반도체디스플레이기술학회지
• /
• 제22권4호
• /
• pp.124-130
• /
• 2023

Recently, fan out wafer level packaging, which enables high integration, miniaturization, and low cost, is being rapidly applied in the semiconductor industry. In particular, FOWLP is attracting attention in the mobile and Internet of Things fields, and is recognized as a core technology that will lead to technological advancements such as 5G, self-driving cars, and artificial intelligence in the future. However, as chip density and package size within the package increase, FOWLP warpage is emerging as a major problem. These problems have a direct impact on the reliability and electrical performance of semiconductor products, and in particular, cause defects such as vacuum leakage in the manufacturing process or lack of focus in the photolithography process, so technical demands for solving them are increasing. In this paper, warpage simulation according to the thickness of FOWLP material was performed using finite element analysis. The thickness range was based on the history of similar packages, and as a factor causing warpage, the curing temperature of the materials undergoing the curing process was applied and the difference in deformation due to the difference in thermal expansion coefficient between materials was used. At this time, the stacking order was reflected to reproduce warpage behavior similar to reality. After performing finite element analysis, the influence of each variable on causing warpage was defined, and based on this, it was confirmed that warpage was controlled as intended through design modifications.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2013년도 춘계학술대회 논문집
• /
• pp.1223-1224
• /
• 2013

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2011년도 춘계학술대회 논문집
• /
• pp.755-756
• /
• 2011

• 품질경영학회지
• /
• 제29권3호
• /
• pp.86-96
• /
• 2001

The objective of this research is to develop a robust design methodology for plastic injection molded parts wherein warpage will be minimized by a complex method which is a kind of a simple direct search method. The design space considered for optimization is divided Into two sub-design space : mold and process conditions. Warpage is quantified using the Moldflow injection molding simulation software. The design methodology was applied to an actual part of a fax machine, the Guide-ASF model, through two different design policies. The significance of this study is the synthesis of a computer simulation of injection molding process and optimization technique to determine the optimal robust design solution.