In spacecraft electronic devices,the deformation of solder balls within ball grid array(BGA)packages poses a significant risk of system failure.Therefore,accurately measuring the mechanical behavior of solder balls is...In spacecraft electronic devices,the deformation of solder balls within ball grid array(BGA)packages poses a significant risk of system failure.Therefore,accurately measuring the mechanical behavior of solder balls is crucial for ensuring the safety and reliability of spacecraft.Although finite element simulations have been extensively used to study solder ball deformation,there is a significant lack of experimental validation,particularly under thermal cycling conditions.This is due to the challenges in accurately measuring the internal deformations of solder balls and eliminating the rigid body displacement introduced during ex-situ thermal cycling tests.In this work,an ex-situ three-dimensional deformation measurement method using X-ray computed tomography(CT)and digital volume correlation(DVC)is proposed to overcome these obstacles.By incorporating the layer-wise reliability-guided displacement tracking(LW-RGDT)DVC with a singular value decomposition(SVD)method,this method enables accurate assessment of solder ball mechanical behavior in BGA packages without the influence of rigid body displacement.Experimental results reveal that BGA structures exhibit progressive convex deformation with increased thermal cycling,particularly in peripheral solder balls.This method provides a reliable and effective tool for assessing internal deformations in electronic packages under ex-situ conditions,which is crucial for their design optimization and lifespan predictions.展开更多
Voids are one of the major defects in ball grid array （BGA） solder joints due to a large amount of outgassing flux that gets entrapped during reflow. X-ray nondestructive machines are used to make voids visible ...Voids are one of the major defects in ball grid array （BGA） solder joints due to a large amount of outgassing flux that gets entrapped during reflow. X-ray nondestructive machines are used to make voids visible as lighter areas inside the solder joints in X-ray images for detection However, it has always been difficult to analyze this problem automatically because of some challenges such as noise, inconsistent lighting and void-like artifacts. This study realized accurate extraction and automatic a-nalysis of void defects in solder joints by adopting a technical proposal, in which Otsu algorithm was used to segment solder balls and void defects were extracted through opening and closing operations and top-hat transformation in mathematical mor-phology. Experimental results show that the technical proposal mentioned here has good robustness and can be applied in the detection of voids in BGA solder joints.展开更多
Ball grid arrays (BGAs) have been used in the production of electronic devices/assemblies because of their advantages of small size, high I/O port density, etc. However, BGA voids can degrade the performance of the bo...Ball grid arrays (BGAs) have been used in the production of electronic devices/assemblies because of their advantages of small size, high I/O port density, etc. However, BGA voids can degrade the performance of the board and cause failure. In this paper, a novel blob filter is proposed to automatically detect BGA voids presented in X-ray images. The proposed blob filter uses the local image gradient magnitude and thus is not influenced by image brightness, void position, or component interference. Different sized average box filters are employed to analyze the image in multi-scale, and as a result, the proposed blob filter is robust to void size. Experimental results show that the proposed method obtains void detection accuracy of up to 93.47% while maintaining a low false ratio. It outperforms another recent algorithm based on edge detection by 40.69% with respect to the average detection accuracy, and by 16.91% with respect to the average false ratio.展开更多
A ball grid array （BGA） package based on Si interposer with through silicon via （TSV） was de- signed. Thermal behaviors of the designed BGA with Si interposer has been analyzed and compared to a conventional BGA w...A ball grid array （BGA） package based on Si interposer with through silicon via （TSV） was de- signed. Thermal behaviors of the designed BGA with Si interposer has been analyzed and compared to a conventional BGA with BT substrate in the approach of finite element modeling （FEM）. The Si interposer with TSV was then fabricated and the designed BGA package was demonstrated. The designed BGA pack- age includes a 100 ~m thick Si interposer, which has redistribution copper traces on both sides. Through vias with 25 to 40 ~m diameter were fabricated on the Si interposer using deep reactive ion etching （DRIE）, plasma enhanced chemical vapor deposition （PECVD）, copper electroplating and chemical mechanical pol- ishing （CMP）, etc. TSV in the designed interposer is used as electrical interconnections and cooling chan- nels. 5 mm by 5 mm and 10 mm by 10 mm thermal chips were assembled on the Si interposer.展开更多
文摘In spacecraft electronic devices,the deformation of solder balls within ball grid array(BGA)packages poses a significant risk of system failure.Therefore,accurately measuring the mechanical behavior of solder balls is crucial for ensuring the safety and reliability of spacecraft.Although finite element simulations have been extensively used to study solder ball deformation,there is a significant lack of experimental validation,particularly under thermal cycling conditions.This is due to the challenges in accurately measuring the internal deformations of solder balls and eliminating the rigid body displacement introduced during ex-situ thermal cycling tests.In this work,an ex-situ three-dimensional deformation measurement method using X-ray computed tomography(CT)and digital volume correlation(DVC)is proposed to overcome these obstacles.By incorporating the layer-wise reliability-guided displacement tracking(LW-RGDT)DVC with a singular value decomposition(SVD)method,this method enables accurate assessment of solder ball mechanical behavior in BGA packages without the influence of rigid body displacement.Experimental results reveal that BGA structures exhibit progressive convex deformation with increased thermal cycling,particularly in peripheral solder balls.This method provides a reliable and effective tool for assessing internal deformations in electronic packages under ex-situ conditions,which is crucial for their design optimization and lifespan predictions.
基金National Science and Technology Major Project of the Ministry of Science And Technology of China(No.2013YQ240803)Shanxi Programs for Science and Technology Development(Nos.20140321010-02,201603D121040-1)Scientific and Technological Innovation Programs of Higher Education Institutions of Shanxi Province(No.2013063)
文摘Voids are one of the major defects in ball grid array （BGA） solder joints due to a large amount of outgassing flux that gets entrapped during reflow. X-ray nondestructive machines are used to make voids visible as lighter areas inside the solder joints in X-ray images for detection However, it has always been difficult to analyze this problem automatically because of some challenges such as noise, inconsistent lighting and void-like artifacts. This study realized accurate extraction and automatic a-nalysis of void defects in solder joints by adopting a technical proposal, in which Otsu algorithm was used to segment solder balls and void defects were extracted through opening and closing operations and top-hat transformation in mathematical mor-phology. Experimental results show that the technical proposal mentioned here has good robustness and can be applied in the detection of voids in BGA solder joints.
基金supported by the Dankook University 2010 Funding for Research Institute of Information and Communication Convergence Technology (RICT),Korea
文摘Ball grid arrays (BGAs) have been used in the production of electronic devices/assemblies because of their advantages of small size, high I/O port density, etc. However, BGA voids can degrade the performance of the board and cause failure. In this paper, a novel blob filter is proposed to automatically detect BGA voids presented in X-ray images. The proposed blob filter uses the local image gradient magnitude and thus is not influenced by image brightness, void position, or component interference. Different sized average box filters are employed to analyze the image in multi-scale, and as a result, the proposed blob filter is robust to void size. Experimental results show that the proposed method obtains void detection accuracy of up to 93.47% while maintaining a low false ratio. It outperforms another recent algorithm based on edge detection by 40.69% with respect to the average detection accuracy, and by 16.91% with respect to the average false ratio.
基金Supported by the National S&T Major Project (No. 2009ZX02038)the National High-Tech Research and Development (863) Program of China (No. 2009AA04321)supported by Cisco Systems Inc
文摘A ball grid array （BGA） package based on Si interposer with through silicon via （TSV） was de- signed. Thermal behaviors of the designed BGA with Si interposer has been analyzed and compared to a conventional BGA with BT substrate in the approach of finite element modeling （FEM）. The Si interposer with TSV was then fabricated and the designed BGA package was demonstrated. The designed BGA pack- age includes a 100 ~m thick Si interposer, which has redistribution copper traces on both sides. Through vias with 25 to 40 ~m diameter were fabricated on the Si interposer using deep reactive ion etching （DRIE）, plasma enhanced chemical vapor deposition （PECVD）, copper electroplating and chemical mechanical pol- ishing （CMP）, etc. TSV in the designed interposer is used as electrical interconnections and cooling chan- nels. 5 mm by 5 mm and 10 mm by 10 mm thermal chips were assembled on the Si interposer.
