Technical Barriers and Development of Cu Wirebonding in Nanoelectronics Device Packaging

Gan, Chong Leong; Ng, EK; Chan, B. L.; Hashim, U.; Classe, F. C.

doi:10.1155/2012/173025

Cited by 37 publications

(26 citation statements)

References 21 publications

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“…1 to 3 below. Cracking usually starts at the Cu ball bond periphery, and it will propagate toward the center of the Cu ball bond [9,10,13]. There is a possibility that under moist conditions, internal oxidation of intermetallic phases can result in oxidation of aluminum, precipitation of the noble metal (Au or Cu), and generation of hydrogen.…”

Section: Resultsmentioning

confidence: 99%

Extended reliability of gold and copper ball bonds in microelectronic packaging

Gan

Francis²,

Chan³

et al. 2013

Gold Bull

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Wire bonding is the predominant mode of interconnection in microelectronic packaging. Gold wire bonding has been refined again and again to retain control of interconnect technology due to its ease of workability and years of reliability data. Copper (Cu) wire bonding is well known for its advantages such as cost-effectiveness and better electrical conductivity in microelectronic packaging. However, extended reliabilities of Cu wire bonding are still unknown as of now. Extended reliabilities of Au and Pd-coated Cu (Cu) ball bonds are useful technical information for Au and Cu wire deployment in microelectronic packaging. This paper discusses the influence of wire type and mold compound effect on the package reliability and after several component reliability stress tests. Failure analysis has been conducted to identify its associated failure mechanisms after the package conditions for Au and Cu ball bonds. Extended reliabilities of both wire types are investigated after unbiased HAST (UHAST), temperature cycling (TC), and high-temperature storage life test (HTSL) at 150, 175, and 200°C aging temperatures. Weibull plots have been plotted for each reliability stress. Obviously, Au ball bond is found with longer time to failure in unbiased HAST stress compared to Cu ball bonds for both mold compounds. Cu wire exhibits equivalent package and or better reliability margin compared to Au ball bonds in TC and HTSL tests. Failure mechanisms of UHAST and TC have been proposed, and its mean time to failure (t 50 ), characteristic life (t 63.2 , η), and shape parameter (ß) have been discussed in this paper. Feasibility of silver (Ag) wire bonding deployment in microelectronic packaging is discussed at the last section in this paper.

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Section: Resultsmentioning

confidence: 99%

Extended reliability of gold and copper ball bonds in microelectronic packaging

Gan

Francis²,

Chan³

et al. 2013

Gold Bull

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“…Figure 1 Proposed CuAl failure mechanism of Cu ball bond opens after UHAST reliability test. [22] The proposed chemical reaction at Cu ball bond area as shown in Eq. 1 to Eq.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 3 illustrates the Cu ball bond oxidation mechanism. Figure 3 Proposed Cu ball bond oxidation mechanism due to long staging at production floor and induce resistive opens after unbiased HAST reliability test [22] The detail dry oxidation of Cu ball liner wall and CuAl IMC wet oxidations are indicated in Eq. 5 to Eq.…”

Section: mentioning

confidence: 99%

Reliability challenges of Cu wire deployment in flash memory packaging

Gan

Ng²,

Chan³

et al. 2012

2012 7th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)

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Cu wirebonding become a great interest of industry in recent years due to its cost effectiveness and electrical and mechanical properties. However, several Cu wire bond reliability challenges are the key concerns in Cu wire deployment in semiconductor packaging. These include Cu wire oxidation and CuAl interface corrosion post HAST or UHAST reliability test. Bond reliability at a Cu wire bond under a humid environment is a major concern in replacing Au wires. Conventional bare Cu bonding wires, in general, are more susceptible to moisture corrosion compared to Au wire. This paper discusses the key reliability challenges Cu wire used in flash fineline BGA package. Cu wire IMD cracking induced by excessive ultrasonic bonding force, Cu wire oxidation due to long staging and Cu ball bond corrosion are discussed in this paper. Failure mechanisms and proposals for reliability improvement have been proposed and discussed in this paper.

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“…The failure mechanisms associated with the galvanic reaction and the out-gassing of H 2 gas in the Au-and Cu-Al bonds during uHAST, including the effect of Cl − ions from the EMC, have already been proposed by Gan et al [39,40]. Liqun et al [5] have proposed that the failure in the Ag-Al bond might be explained by the degradation of the Ag-Al IMCs by galvanic corrosion during a humidity test.…”

Section: Failure Mechanism In the Ag-al Bond During Uhastmentioning

confidence: 93%