Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704505
Y. Sawada, A. Yamaguchi, S. Oka, H. Fujioka
The reliability of plastic ball grid array (PBGA) packages is studied from the viewpoint of materials properties. The reliability of PBGA packages using conventional bismaleimide-triazine type PWB and the authors' original high T/sub g/ epoxy type PWB is evaluated. The PBGA package using the original high T/sub g/ epoxy type PWB has the feature of lower package warpage, and has similar performance in terms of thermal cycling stability and package crack resistance during reflow soldering as compared with the PBGA using the conventional PWB. The crack resistance during reflow soldering for each PBGA is JEDEC level 3. In order to improve crack resistance during reflow soldering, both PWB materials and other factors are investigated. As a result, the low moisture absorption molding compound and the high adhesion strength and fracture strength die attach material are effective for improved crack resistance during reflow soldering. Additionally, we report a new package crack mechanism in this study. The delamination firstly occurs in the gold-plated wire bonding area due to thermomechanical stress. Water vapor pressure accelerates the propagation of delamination or cracking. The delamination propagates in the inner and outer directions along weak adhesion strength interfaces or through low fracture strength materials. It becomes clear that the key properties of materials are moisture absorption, adhesion strength and fracture strength.
{"title":"The reliability of plastic ball grid array package","authors":"Y. Sawada, A. Yamaguchi, S. Oka, H. Fujioka","doi":"10.1109/IEMTIM.1998.704505","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704505","url":null,"abstract":"The reliability of plastic ball grid array (PBGA) packages is studied from the viewpoint of materials properties. The reliability of PBGA packages using conventional bismaleimide-triazine type PWB and the authors' original high T/sub g/ epoxy type PWB is evaluated. The PBGA package using the original high T/sub g/ epoxy type PWB has the feature of lower package warpage, and has similar performance in terms of thermal cycling stability and package crack resistance during reflow soldering as compared with the PBGA using the conventional PWB. The crack resistance during reflow soldering for each PBGA is JEDEC level 3. In order to improve crack resistance during reflow soldering, both PWB materials and other factors are investigated. As a result, the low moisture absorption molding compound and the high adhesion strength and fracture strength die attach material are effective for improved crack resistance during reflow soldering. Additionally, we report a new package crack mechanism in this study. The delamination firstly occurs in the gold-plated wire bonding area due to thermomechanical stress. Water vapor pressure accelerates the propagation of delamination or cracking. The delamination propagates in the inner and outer directions along weak adhesion strength interfaces or through low fracture strength materials. It becomes clear that the key properties of materials are moisture absorption, adhesion strength and fracture strength.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129437791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704539
R. Sawada, H. Nakada, F. Ohira
A new method for accurately and quickly bonding a planar light waveguide circuit (PLC) and a laser diode is proposed. The method is based on simultaneous auto-focusing on marks fabricated on the PLC and laser diode. Bonding equipment constructed to implement the proposed method was accurate within /spl plusmn/1 /spl mu/m. The turnaround time, from picking up the laser diode with vacuum tweezers to completion of the bonding process, was 2 1/4 minutes.
{"title":"Highly accurate and quick bonding for planar lightwave circuit and laser-diode chip","authors":"R. Sawada, H. Nakada, F. Ohira","doi":"10.1109/IEMTIM.1998.704539","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704539","url":null,"abstract":"A new method for accurately and quickly bonding a planar light waveguide circuit (PLC) and a laser diode is proposed. The method is based on simultaneous auto-focusing on marks fabricated on the PLC and laser diode. Bonding equipment constructed to implement the proposed method was accurate within /spl plusmn/1 /spl mu/m. The turnaround time, from picking up the laser diode with vacuum tweezers to completion of the bonding process, was 2 1/4 minutes.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127985425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704635
N. Nishizuka, M. Tahara, M. Mohemaiti
Directional couplers are utilized in many communication systems and measuring instruments. The coupler is usually made of two-conductor coupled transmission-lines in the VHF and UHF ranges. Since the coupler becomes large in these frequency ranges, the bifilar line winding can be used to reduce its size. Then, the phase velocity of u- and b-modes become unequal v/sub u//spl ne/v/sub b/, which leads to deterioration of the isolation characteristics of the coupler. In this paper, we analyse the three or more conductor winding type directional couplers, whose isolation characteristics are high. The theoretical and experimental characteristics agree well.
{"title":"Analysis of small-sized winding type directional coupler","authors":"N. Nishizuka, M. Tahara, M. Mohemaiti","doi":"10.1109/IEMTIM.1998.704635","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704635","url":null,"abstract":"Directional couplers are utilized in many communication systems and measuring instruments. The coupler is usually made of two-conductor coupled transmission-lines in the VHF and UHF ranges. Since the coupler becomes large in these frequency ranges, the bifilar line winding can be used to reduce its size. Then, the phase velocity of u- and b-modes become unequal v/sub u//spl ne/v/sub b/, which leads to deterioration of the isolation characteristics of the coupler. In this paper, we analyse the three or more conductor winding type directional couplers, whose isolation characteristics are high. The theoretical and experimental characteristics agree well.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122313144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704525
S. Senda, Y. Hayashi, K. Nakayama
Although many kinds of thick film pastes are used at present for plasma display panels (PDPs), photosensitive pastes are often used instead of conventional printing methods due to the large size and finer patterning of PDPs. The characteristics of photosensitive paste, however, change depending on each of the drying, exposure, development and firing conditions. It is thus essential to examine the particular forming conditions required to obtain a stable patterned film. In this paper, we found the appropriate forming conditions by researching failure modes at the development and firing stages using photosensitive silver paste and black stripe paste. We also compared photosensitive pastes in terms of patterning efficiency with the conventional printing method, and studied advantages and disadvantages when applied to actual PDPs.
{"title":"Application of photo sensitive pastes for PDP","authors":"S. Senda, Y. Hayashi, K. Nakayama","doi":"10.1109/IEMTIM.1998.704525","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704525","url":null,"abstract":"Although many kinds of thick film pastes are used at present for plasma display panels (PDPs), photosensitive pastes are often used instead of conventional printing methods due to the large size and finer patterning of PDPs. The characteristics of photosensitive paste, however, change depending on each of the drying, exposure, development and firing conditions. It is thus essential to examine the particular forming conditions required to obtain a stable patterned film. In this paper, we found the appropriate forming conditions by researching failure modes at the development and firing stages using photosensitive silver paste and black stripe paste. We also compared photosensitive pastes in terms of patterning efficiency with the conventional printing method, and studied advantages and disadvantages when applied to actual PDPs.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116072807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704498
M. Lin
This paper summarizes the current status of Taiwan microelectronics industry, including both semiconductor technology and flat panel displays, and presents the technology developments leading to the strategic goals of Taiwan towards the year 2000 and beyond.
{"title":"Technology trends of microelectronics in Taiwan","authors":"M. Lin","doi":"10.1109/IEMTIM.1998.704498","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704498","url":null,"abstract":"This paper summarizes the current status of Taiwan microelectronics industry, including both semiconductor technology and flat panel displays, and presents the technology developments leading to the strategic goals of Taiwan towards the year 2000 and beyond.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131210487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704543
H. Watanabe, H. Honma
Generally, palladium catalyst treatment is applied to initiate the electroless Ni-P plating on the copper patterns because copper does not have a catalytic action for the oxidation of hypophosphite. However, when electroless nickel films are deposited on circuit boards with high density copper patterns by this process, many extraneous deposits are observed after electroless nickel plating. If electroless nickel plating is progressed on the copper patterns without palladium catalyst treatment, extraneous nickel depositions are inhibited. Direct electroless nickel plating of the copper patterns by the addition of dimethyl amine borane (DMAB) as a second reducing agent into the plating bath is investigated.
{"title":"Direct electroless nickel plating on copper circuits using DMAB as a second reducing agent","authors":"H. Watanabe, H. Honma","doi":"10.1109/IEMTIM.1998.704543","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704543","url":null,"abstract":"Generally, palladium catalyst treatment is applied to initiate the electroless Ni-P plating on the copper patterns because copper does not have a catalytic action for the oxidation of hypophosphite. However, when electroless nickel films are deposited on circuit boards with high density copper patterns by this process, many extraneous deposits are observed after electroless nickel plating. If electroless nickel plating is progressed on the copper patterns without palladium catalyst treatment, extraneous nickel depositions are inhibited. Direct electroless nickel plating of the copper patterns by the addition of dimethyl amine borane (DMAB) as a second reducing agent into the plating bath is investigated.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"160 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134071281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704629
T. Nagasaka, Y. Ootani, K. Oka, M. Miyairi, K. Naito
When burn-in testing was performed at high temperature with opposing electrodes which were formed on the thick film Ag conductor, a short occurred between the electrodes. We realized that this was due to the electric field strength in addition to the temperature. Moreover, we found the cause of this short from the results of our investigation: in the conductor firing process, Ag is melted with glass inside the conductor and this mixture of Ag and glass disperses and accumulates near the electrode. For this reason, we improved the glass quality inside the conductor to decrease the degree of dispersion of the Ag/glass mixture during firing of the conductor and avoided high temperature migration.
{"title":"High temperature migration of thick film conductor","authors":"T. Nagasaka, Y. Ootani, K. Oka, M. Miyairi, K. Naito","doi":"10.1109/IEMTIM.1998.704629","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704629","url":null,"abstract":"When burn-in testing was performed at high temperature with opposing electrodes which were formed on the thick film Ag conductor, a short occurred between the electrodes. We realized that this was due to the electric field strength in addition to the temperature. Moreover, we found the cause of this short from the results of our investigation: in the conductor firing process, Ag is melted with glass inside the conductor and this mixture of Ag and glass disperses and accumulates near the electrode. For this reason, we improved the glass quality inside the conductor to decrease the degree of dispersion of the Ag/glass mixture during firing of the conductor and avoided high temperature migration.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132085125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704663
T. Hamano, Y. Ikemoto, A. Okada, K. Asada, M. Abe, Y. Kubota
We developed a 420-ball enhanced BGA (EBGA) package that can accommodate a 500 MHz ASIC with 15 W power consumption. This package uses a low voltage differential signal with 400 mV full amplitude and 240 ps risetime as its highest speed signal, and consists of 8 pairs of differential signals. Each pair is composed of 2 signals with an isometric length. Two pairs have an identical length and form a channel, i.e. a parallel transmission path. This package has a nonstub configuration using electroless nickel and gold plating. This package also has a short ground loop running on the sidewall of the cavity. A time domain waveform was used for simulation of the electrical characteristics of this package. Then, the time domain waveform in an actual package was measured at risetime of 120 and 240 ps. As a result, the simulated time domain waveform agreed well with the measurements. We confirmed that the electrical performance of this package allows accommodation of a 500 MHz ASIC, and can achieve parallel transmission in a 500 MHz system.
{"title":"Electrical characterization of a 500 MHz frequency EBGA package","authors":"T. Hamano, Y. Ikemoto, A. Okada, K. Asada, M. Abe, Y. Kubota","doi":"10.1109/IEMTIM.1998.704663","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704663","url":null,"abstract":"We developed a 420-ball enhanced BGA (EBGA) package that can accommodate a 500 MHz ASIC with 15 W power consumption. This package uses a low voltage differential signal with 400 mV full amplitude and 240 ps risetime as its highest speed signal, and consists of 8 pairs of differential signals. Each pair is composed of 2 signals with an isometric length. Two pairs have an identical length and form a channel, i.e. a parallel transmission path. This package has a nonstub configuration using electroless nickel and gold plating. This package also has a short ground loop running on the sidewall of the cavity. A time domain waveform was used for simulation of the electrical characteristics of this package. Then, the time domain waveform in an actual package was measured at risetime of 120 and 240 ps. As a result, the simulated time domain waveform agreed well with the measurements. We confirmed that the electrical performance of this package allows accommodation of a 500 MHz ASIC, and can achieve parallel transmission in a 500 MHz system.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121266141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704674
A. Stanfield, S. Mannan
A feasibility study into alternative methods of producing interconnection between a PCB and flip chip has been undertaken. A number of initial ideas were investigated, the least promising being discarded at an early stage, whilst the ideas showing the greatest chance of success were subject to a more rigorous examination. Of the initial ideas, the most promising were amalgam materials and magnetic alignment of ferromagnetic particles. These two ideas were combined to produce a new type of anisotropic conducting adhesive (ACA) which may have the potential to overcome problems due to z-axis irregularities and have the ability to form fine pitch metallurgical bonding. In order to promote bonding, amalgam compositions that enhance surface wetting while retaining good mechanical properties have been investigated. The possibility of incorporating liquid/semi-solid metallic interconnects within the ACA which retain contact during the thermal expansion of the polymeric materials was also explored. During the course of the study, various techniques such as DSC and SEM have been used to characterise the thermal stability of Ga based alloys and discrepancies with current phase diagrams have been found.
{"title":"Gallium based interconnects for flip-chip assembly","authors":"A. Stanfield, S. Mannan","doi":"10.1109/IEMTIM.1998.704674","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704674","url":null,"abstract":"A feasibility study into alternative methods of producing interconnection between a PCB and flip chip has been undertaken. A number of initial ideas were investigated, the least promising being discarded at an early stage, whilst the ideas showing the greatest chance of success were subject to a more rigorous examination. Of the initial ideas, the most promising were amalgam materials and magnetic alignment of ferromagnetic particles. These two ideas were combined to produce a new type of anisotropic conducting adhesive (ACA) which may have the potential to overcome problems due to z-axis irregularities and have the ability to form fine pitch metallurgical bonding. In order to promote bonding, amalgam compositions that enhance surface wetting while retaining good mechanical properties have been investigated. The possibility of incorporating liquid/semi-solid metallic interconnects within the ACA which retain contact during the thermal expansion of the polymeric materials was also explored. During the course of the study, various techniques such as DSC and SEM have been used to characterise the thermal stability of Ga based alloys and discrepancies with current phase diagrams have been found.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122361867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-15DOI: 10.1109/IEMTIM.1998.704703
K. Kotaka, Y. Abe, Y. Homma
Epoxy acid anhydride materials are normally used as flow-type underfill materials. However, the underfill materials of this type, when humidified, tend to cause delamination at the interface with chips in solder reflow. To solve this problem, increasing the adhesive property of underfill material was attempted by investigating the relationship of adhesion strength with the glass transition temperature, high-temperature elastic modulus, and coefficient of moisture absorption for different resin compositions and different filler contents. As a result, the adhesion strength is higher and soldering heat resistance was found to be improved with higher glass transition temperature compositions. On the other hand, the adhesion strength was not affected by changes in the filler content. Based on these findings, an underfill material with high adhesion strength was developed. This new material did not cause delamination, even when treated by the level 2 JEDEC preconditioning test.
{"title":"The new underfill materials with high adhesion strength for flip-chip applications","authors":"K. Kotaka, Y. Abe, Y. Homma","doi":"10.1109/IEMTIM.1998.704703","DOIUrl":"https://doi.org/10.1109/IEMTIM.1998.704703","url":null,"abstract":"Epoxy acid anhydride materials are normally used as flow-type underfill materials. However, the underfill materials of this type, when humidified, tend to cause delamination at the interface with chips in solder reflow. To solve this problem, increasing the adhesive property of underfill material was attempted by investigating the relationship of adhesion strength with the glass transition temperature, high-temperature elastic modulus, and coefficient of moisture absorption for different resin compositions and different filler contents. As a result, the adhesion strength is higher and soldering heat resistance was found to be improved with higher glass transition temperature compositions. On the other hand, the adhesion strength was not affected by changes in the filler content. Based on these findings, an underfill material with high adhesion strength was developed. This new material did not cause delamination, even when treated by the level 2 JEDEC preconditioning test.","PeriodicalId":260028,"journal":{"name":"2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225)","volume":"164 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122558328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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