Influence of surface cleanness on ultrasonic ball bondability of Au wire on to Au, Cu and Al pads

Kajiwara, Ryoichi; Takahashi, Tōru; Tsubosaki, Kunihiro; Watanabe, Hitoshi

doi:10.1080/09507119809455138

Cited by 3 publications

(3 citation statements)

References 5 publications

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“…With the chips and substrate prepared, the transplanted chips were attached onto the substrate using H70E epoxy die attach, before undergoing thermal curing to harden the epoxy in place. After the die attachment, the transplanted sample was subjected to plasma cleaning to ensure the surface cleanliness of the bond pads for more successful wire rebonding process [10] later. New wire bonds were then created on the sample to re-establish electrical connections between the transplanted chips and the stitch pads of the substrate.…”

Section: Chips Transplantation Onto Substratementioning

confidence: 99%

“…8. This was most likely due to contaminations on the pad surfaces, from exposure to the surrounding air [12] or emitted species from the die attach during the thermal curing process [13], thereby affecting the adhesion of the gold wire onto them [10]. Plasma cleaning was subsequently conducted on all bonding pads to remove these contaminants for better surface cleanliness, as well as to increase the surface energy of their surfaces [12] to promote better bonding condition.…”

Section: Transplantation Of Chips Onto Substratementioning

confidence: 99%

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Hardware Security Assessment through Repair of Damaged Device

Sim,

Liu,

Kor

et al. 2023

2023 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA)

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In this paper, the feasibility of content access to physically damaged electronic device was explored by performing package level repair through transplantation of its intact silicon chip from its faulty substrate package onto another functional one, and establishment of new electrical connections between them. This functionality restoration of a damaged device was investigated using an integration of various sample preparation techniques commonly used in microelectronics failure analysis. Different decapsulation techniques were also studied to identify the optimal processes for this application. The repaired device was tested to verify the restoration of its functionality, as well as the integrity of the stored data. This may pave the way for new hardware security assessment approach for electronic devices with other types of packaging.

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Section: Chips Transplantation Onto Substratementioning

confidence: 99%

Section: Transplantation Of Chips Onto Substratementioning

confidence: 99%

Hardware Security Assessment through Repair of Damaged Device

Sim,

Liu,

Kor

et al. 2023

2023 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA)

View full text Add to dashboard Cite

show abstract

“…[5][6][7] To overcome this oxidization problem, some researchers have used an inert gas to provide a shielding gas atmosphere between the copper and the air when welding gold wires onto copper pads. [8][9][10] Kajiwara et al 9 studied the effects of the ambient atmosphere on the ultrasonic ball bondability of gold wires onto copper, aluminum, and gold pads, and showed that the bondability deteriorates when the argon gas contains water, acetone and oxygen, but is enhanced when welding is performed in a vacuum. Meanwhile, Jeng et al 10 used argon as a shielding gas to facilitate the thermosonic wire bonding of gold wires onto copper pads.…”

mentioning

confidence: 99%

A Novel Method for Enabling the Thermosonic Wire Bonding of Gold Wire onto Chips with Copper Interconnects

Jeng¹,

Wang

Chiu

et al. 2004

Electrochem. Solid-State Lett.

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The wire bonding of chips with copper interconnects is a challenging issue. The present study develops a method in which the substrates are stored in a temperature and humidity controlled environment such that copper oxide films of appropriate thickness are formed on the substrate prior to the gold-copper thermosonic bonding process. It is shown that this film can be removed during the bonding process, hence rendering the wire bonding process feasible without the requirement for an inert gas environment or the use of metallic cap layers.The miniaturization of electronic components causes the signal delay phenomenon to become increasingly pronounced, and hence limits the ability of these devices to satisfy the requirements of high frequency and high-speed transmission. An effective means of overcoming this problem is to utilize copper rather than aluminum as the interconnect material in integrated circuits, ultralarge scale integration devices, and other electronic components. Compared to aluminum, copper has a lower electrical resistivity and a higher electromigration resistance. 1-4 However, unlike aluminum, copper is easily oxidized at high temperatures and fails to form a passivation oxide layer on its surface, which subsequently protects the sub-layers beneath from excess oxidization. This oxidization phenomenon creates significant problems in the wire bonding process of copper chips. [5][6][7] To overcome this oxidization problem, some researchers have used an inert gas to provide a shielding gas atmosphere between the copper and the air when welding gold wires onto copper pads. [8][9][10] Kajiwara et al. 9 studied the effects of the ambient atmosphere on the ultrasonic ball bondability of gold wires onto copper, aluminum, and gold pads, and showed that the bondability deteriorates when the argon gas contains water, acetone and oxygen, but is enhanced when welding is performed in a vacuum. Meanwhile, Jeng et al. 10 used argon as a shielding gas to facilitate the thermosonic wire bonding of gold wires onto copper pads. The resulting welding quality was analyzed in terms of the observed interfacial microscopic phenomena. The results demonstrated that the use of an appropriate shielding gas resulted in a significant reduction in the copper oxidization induced by the high working temperature of the bonding process. Aoh and Chuang 11 employed an argon shielding technique in the thermosonic wire bonding process to attach gold wires to copper pads at bonding temperatures of 180°C and above. They also conducted high-temperature storage ͑HTS͒ testing to understand the reliability of the Au/Cu ball bond at elevated temperature after prolonged storage, the results shows that the volume of Au-Cu intermetallic compounds formed at the interface is too small to cause degradation of bonding strength after the HTS tests. From the perspective of thermal activation energy, it also indicates that formation of Au-Cu intermetallic compounds at the interface during HTS is more difficult than those between the gold ball and aluminu...

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Reinigung von Metalloberflächen: Mehr als sauber

Vissing

2003

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Influence of surface cleanness on ultrasonic ball bondability of Au wire on to Au, Cu and Al pads

Cited by 3 publications

References 5 publications

Hardware Security Assessment through Repair of Damaged Device

Hardware Security Assessment through Repair of Damaged Device

A Novel Method for Enabling the Thermosonic Wire Bonding of Gold Wire onto Chips with Copper Interconnects

Reinigung von Metalloberflächen: Mehr als sauber

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