Wafer bonding by low-temperature soldering

Lee, Chengkuo; Huang, W. C.; Shie, Jin‐Shown

doi:10.1016/s0924-4247(00)00338-1

Cited by 48 publications

(30 citation statements)

References 7 publications

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“…Under certain bonding conditions, the solder materials interact with Cu or Au to form a bonding joint. [5][6][7][8] This process often involves so-called diffusion soldering, 9 a joining method that combines features of conventional soldering and diffusion bonding processes. The bonding is produced when the substrate metal dissolves into the molten solder and rapidly reacts to form intermetallic compounds (IMCs) with the solder materials.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8] Hermetic packaging has also been developed at temperatures as low as 150°C by using an In-Sn alloy. 8 However, no-one has studied the interfacial reaction of thin-film solder with the substrate and the remelting temperature of the final joint, which are very important in manufacturing operations such as multiple reflows. With a highmelting seal, not only can the sealed packages be engaged in subsequent soldering steps, but also joint creep resistance and dimensional stability can be improved.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Hermetic Seal Using Composite Thin-Film In/Sn Solder as an Intermediate Layer and Its Interdiffusion Reaction with Cu

Yan

Lee

et al. 2008

Journal of Elec Materi

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A bonding joint between Cu metallization and evaporated In/Sn composite solder is produced at a temperature lower than 200°C in air. The effects of bonding temperature and duration on the interfacial bonding strength are studied herein. Cross sections of bonding joints processed at different bonding conditions were examined by scanning electron microscopy (SEM). The optimal condition, i.e., bonding temperature of 180°C for 20 min, was chosen because it gave rise to the highest average bonding strength of 6.5 MPa, and a uniform bonding interface with minimum voids or cracks. Good bond formation was also evidenced by scanning acoustic imaging. For bonding couples of patterned dies, a helium leak rate of 5.8 9 10 -9 atm cc/s was measured, indicating a hermetic seal. The interfacial reaction between Cu and In/Sn was also studied. Intermetallic compounds (IMCs) such as AuIn 2 , Cu 6 Sn 5 , and Cu 11 In 9 were detected by means of x-ray diffraction analysis (XRD), and transmission electron microscopy (TEM) accompanied by energy-dispersive x-ray (EDX) spectroscopy. Chemical composition analysis also revealed that solder interlayers, Sn, and In were completely converted into IMCs by reaction with Cu. All the IMCs formed in the joints have remelting temperatures above 300°C according to the Cu-In, Cu-Sn, and Au-In phase diagrams. Therefore, the joint is able to sustain high service temperatures due to the presence of these IMCs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Hermetic Seal Using Composite Thin-Film In/Sn Solder as an Intermediate Layer and Its Interdiffusion Reaction with Cu

Yan

Lee

et al. 2008

Journal of Elec Materi

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“…First Au/In, Ag/In, and Cu/In metal systems were applied [18]; however, the most common alloys in the semiconductor industry nowadays are Au/Sn, Ag/Sn, Cu/Sn, and Ni/Sn. The use of specific intermediate alloys as In/Sn or Ga/ Sn facilitates additional temperature reduction (160 °C) as reported in [19,20].…”

Section: Introductionmentioning

confidence: 99%

Reliable aluminum contact formation by electrostatic bonding

Kárpáti¹,

Pap²,

Radnóczi³

et al. 2015

J. Micromech. Microeng.

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The paper presents a detailed study of a reliable method developed for aluminum fusion wafer bonding assisted by the electrostatic force evolving during the anodic bonding process. The IC-compatible procedure described allows the parallel formation of electrical and mechanical contacts, facilitating a reliable packaging of electromechanical systems with backside electrical contacts. This fusion bonding method supports the fabrication of complex microelectromechanical systems (MEMS) and micro-opto-electromechanical systems (MOEMS) structures with enhanced temperature stability, which is crucial in mechanical sensor applications such as pressure or force sensors. Due to the applied electrical potential of −1000 V the Al metal layers are compressed by electrostatic force, and at the bonding temperature of 450 °C intermetallic diffusion causes aluminum ions to migrate between metal layers.

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“…For example, image sensor module requires a relative low process temperature (below 200 • C) because it contains polymer structures like micro-lens which is sensitive to the temperature [8]. Various low temperature wafer bonding technologies have been investigated and they are categorized as two main approaches, i.e., direct bonding using special surface treatment techniques (such as plasma surface activated bonding [9], atom beam irradiation [10]) and intermediate layer bonding using polymers [11] and low temperature solders based on diffusion soldering method [12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%