2005 Fiscal Year Final Research Report Summary
Development of Preventive Means against Joint Defects in Anodically-bonded Joints Induced by Application of Reverse Voltage
| Project/Area Number |
16560632
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Material processing/treatments
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
TAKAHASHI Makoto Osaka University, Joining and Welding Research Institute, Assistant Professor, 接合科学研究所, 助手 (10294133)
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Keywords | anodic bonding / ion substitution / suppression of joint defects / control of precipitation / borosilicate glass / silicon / silver / Kovar alloy |
|---|
| Research Abstract |
Preventive means against joint defects in anodically-bonded joints induced by application of the reverse voltage was developed from the aspect of inhibition of accumulation of alkali ions at the joint interface that caused the joint defects. Alkali ions are the cause of the joint defects, but they play an essential role in the mechanism of the anodic bonding. Hence, Alkali-ion-free glass is not joinable with anodic bonding. Therefore, effect of replacement of alkali ions with some other cation that is mobile in glass and can substitute for alkali ions in anodic bonding was examined. The major alkali metal component of borosilicate glass Corning 7740 was sodium. After substitution of silver for sodium component, this glass showed comparable joinability by anodic bonding to usual glass, and joint defect did not form in the joints of the glass whose sodium component was replaced by silver. The same treatment was applied to the Corning 7056 glass, borosilicate glass whose alkali metal comp
… More
onents were differ from that of corning 7740. Decrease in the strength of the joint of that glass with application of the reverse voltage was suppressed by ion substitution. When the reverse voltage was applied to the joints of the glass whose alkali ion component was replaced by silver, the silver ions accumulated in the joint area and formed precipitates of metallic silver with specific morphology. This phenomenon did not cause joint defects, but it can cause problems in some applications. At the same time, it may be useful as a method to form structures of electric conductor in glass. Hence, controlling factors of the formation and growth of the precipitates were investigated, and it was found that the frequency of formation of local current passes in the cation depletion layer that formed in the glass adjacent to the joint interface during anodic bonding influenced the size and number density of the precipitates, and shortening of the bonding time, increase in the reverse voltage and application temperature of the reverse voltage caused miniaturization and increase in number density of the precipitates. Less
|
Research Products
(11 results)
