Wettable flank routable thin MicroLeadFrame for automotive applications

Kim, Byong Jin; Jeon, HyeongIl; Gijeong, Kim,; Cho, Nam-Hee; Khim, JinYoung; Kim, Yeong K.

doi:10.1016/j.microrel.2022.114602

Cited by 6 publications

(3 citation statements)

References 15 publications

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“…With the development of semiconductor devices towards higher integration, the requirements on size accuracy and surface quality of the lead frames are more and more strict [1]. At present, the high-precision lead frame is mainly processed by etching [2,3], and the materials are the high-strength and high conductivity Cu alloys [4,5]. Etching is a precise material reduction processing method which selectively dissolves the unnecessary part of the Cu alloy strips to obtain the devices with specific size and shape.…”

Section: Introductionmentioning

confidence: 99%

Influences of Etchants on Etched Surfaces of High-Strength and High Conductivity Cu Alloy of Different Processing States

Fang,

Zhang,

Zhang

et al. 2024

Preprint

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With continuous increase in integration of the semiconductor devices, the requirements on size accuracy and surface quality of the etched lead frame are higher. The etchant is a key factor on etching process and etched surface quality, while effects of the difference in etchants on microscopic etched surface morphology of the Cu alloy have not been directly studied. In this study, the aqua regia, acidic FeCl3 and CuCl2 solutions were used as etchants, and the CuCrSn alloy specimens with different microstructure were etched and characterized. The results show that the etching rate in aqua regia is high, and the grain orientation, grain boundary (GB) and dislocation have significant influence on the local etching rate. The preferential etching of some atomic planes forms steps between grains with different orientations, and the preferential etching around the GB and dislocation group forms grooves, resulting in high surface roughness. For etching of the FeCl3 and CuCl2 etchants, the steps and grooves become blurred, and almost invisible on the surface etched by the CuCl2 etchant, thus the surface roughness is much lower. The CuCrSn alloy surface etched by the aqua regia is clean, with little Cr-rich particles, while high density Cr-rich particles are remained on the surfaces etched with the FeCl3 and CuCl2 etchants. For the same kind of etchant, the ion concentration can affect the etching mechanism and etching surface morphology.

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Section: Introductionmentioning

confidence: 99%

Influences of Etchants on Etched Surfaces of High-Strength and High Conductivity Cu Alloy of Different Processing States

Fang,

Zhang,

Zhang

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…With the increased integration of semiconductor devices, the requirements of the size accuracy and surface quality of lead frames are becoming more and more strict [1]. At present, high-precision lead frames are mainly processed by etching [2,3], and the materials are high-strength and high-conductivity Cu alloys [4,5]. Etching is a precise material reduction method which selectively dissolves the unnecessary part of the alloy strips to obtain devices with a specific size and shape.…”

Section: Introductionmentioning

confidence: 99%

Influence of Etchants on Etched Surfaces of High-Strength and High-Conductivity Cu Alloy of Different Processing States

Fang,

Zhang,

Zhang

et al. 2024

Materials

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With the continuous integration of semiconductor devices, the requirements of the size accuracy and surface quality of etched lead frames are stricter. The etchant is a key factor in the etching process and etched surface quality, while the effects of the difference in etchants on the etched surface morphology of Cu alloy have not been directly studied. In this study, aqua regia, acidic FeCl3 and two CuCl2 solutions were used as etchants, and different CuCrSn specimens were etched and characterized. The results show that the etching rate in aqua regia is high, and the grain orientation, grain boundary (GB) and dislocations have significant influences on the local etching rate. The preferential etching of some atomic planes forms steps between the grains with different orientations, and preferential etching around the GB and dislocation group forms grooves, resulting in high surface roughness. For the surfaces etched by the FeCl3 and CuCl2 etchants, the steps and grooves are blurred; thus, they are less rough. The CuCrSn alloy surface etched by the aqua regia is clean, with little Cr-rich particles, while high-density Cr-rich particles remain on the surfaces etched by the FeCl3 and CuCl2 etchants. For the same kind of etchant, the ion concentration can affect the etching mechanism, rate and the etched surface morphology.

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“…But there are still no robust solutions to accommodate high thermal and electrical performance like leadframe package (McGibney and Barrett, 2006;Li et al, 2018;Wu et al, 2014) while gives design flexibility. In response to this need, routable molded leadframe (rtMLF), combining the two advantages of the high reliability of a leadframe and the design flexibility of a laminate package, has been developed (Kim et al, 2022a(Kim et al, , 2022b. rtMLF has a structure in which the upper layer (Top) and the lower layer (Land) are separated but one frame with insulating the preetched leadframe by laminating or screen printing with resin.…”

Section: Introductionmentioning

confidence: 99%

The advanced leadless leadframe package and its characteristics

Kim¹,

Jeon²,

Gijeong³

et al. 2023

Self Cite

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Purpose The purpose of this study is to offer the advanced leadless leadframe package which achieve small form factor and high thermal and electrical performance, according to the continuous market requirement. Because of demand and trends, new package structures that can accommodate many pins (I/Os) while maintaining the excellent thermal and electrical properties of the leadframe package was studied. Different from conventional leadframe and laminate packages, it must have the large-exposed pad for thermal dissipation and design flexibility to deploy signal, ground and power selectively. Design/methodology/approach In this study, the routable molded leadframe (rtMLF®) package applying the pre-resin MLF substrate was introduced. The structural advantages, in terms of design flexibility, were checked by adopting the specific electrical feature. Also, the excellence of thermal and electrical performance was confirmed by simulation. The sample was manufactured, and its package robustness was validated by reliability test. Findings rtMLF package that enables one layer substrate but routable pattern on top layer differently from existing leadframe package was developed and studied if it overcome the limitations of leadframe and laminate products. Asymmetric land layout was designed and special features to keep electrical interference was applied to prove design flexibility. The thermal and electrical simulation has been executed to check the advantages. And key differentiations were identified. Finally, actual sample was manufactured, and structural robustness was validated by package level and board level reliability. Originality/value The differentiation of new semiconductor package was introduced and its excellence was verified by electrical and thermal simulation as well as reliability test. It is expected to be adopted for alternative solutions not covered by the existing products.

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Wettable flank routable thin MicroLeadFrame for automotive applications

Cited by 6 publications

References 15 publications

Influences of Etchants on Etched Surfaces of High-Strength and High Conductivity Cu Alloy of Different Processing States

Influences of Etchants on Etched Surfaces of High-Strength and High Conductivity Cu Alloy of Different Processing States

Influence of Etchants on Etched Surfaces of High-Strength and High-Conductivity Cu Alloy of Different Processing States

The advanced leadless leadframe package and its characteristics

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