• Title/Summary/Keyword: So-seong

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Fine-Pitch Solder on Pad Process for Microbump Interconnection

  • Bae, Hyun-Cheol;Lee, Haksun;Choi, Kwang-Seong;Eom, Yong-Sung
    • ETRI Journal
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    • 제35권6호
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    • pp.1152-1155
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    • 2013

  • A cost-effective and simple solder on pad (SoP) process is proposed for a fine-pitch microbump interconnection. A novel solder bump maker (SBM) material is applied to form a 60-${\mu}m$ pitch SoP. SBM, which is composed of ternary Sn3.0Ag0.5Cu (SAC305) solder powder and a polymer resin, is a paste material used to perform a fine-pitch SoP through a screen printing method. By optimizing the volumetric ratio of the resin, deoxidizing agent, and SAC305 solder powder, the oxide layers on the solder powder and Cu pads are successfully removed during the bumping process without additional treatment or equipment. Test vehicles with a daisy chain pattern are fabricated to develop the fine-pitch SoP process and evaluate the fine-pitch interconnection. The fabricated Si chip has 6,724 bumps with a 45-${\mu}m$ diameter and 60-${\mu}m$ pitch. The chip is flip chip bonded with a Si substrate using an underfill material with fluxing features. Using the fluxing underfill material is advantageous since it eliminates the flux cleaning process and capillary flow process of the underfill. The optimized bonding process is validated through an electrical characterization of the daisy chain pattern. This work is the first report on a successful operation of a fine-pitch SoP and microbump interconnection using a screen printing process.

  • https://doi.org/10.4218/etrij.13.0213.0284 인용 PDF KSCI

Maskless Screen Printing Process using Solder Bump Maker (SBM) for Low-cost, Fine-pitch Solder-on-Pad (SoP) Technology

  • Choi, Kwang-Seong;Lee, Haksun;Bae, Hyun-Cheol;Eom, Yong-Sung
    • 마이크로전자및패키징학회지
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    • 제20권4호
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    • pp.65-68
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    • 2013

  • A novel bumping process using solder bump maker (SBM) is developed for fine-pitch flip chip bonding. It features maskless screen printing process. A selective solder bumping mechanism without the mask is based on the material design of SBM. Maskless screen printing process can implement easily a fine-pitch, low-cost, and lead-free solder-on-pad (SoP) technology. Its another advantage is ternary or quaternary lead-free SoP can be formed easily. The process includes two main steps: one is the thermally activated aggregation of solder powder on the metal pads on a substrate and the other is the reflow of the deposited powder on the pads. Only a small quantity of solder powder adjacent to the pads can join the first step, so a quite uniform SoP array on the substrate can be easily obtained regardless of the pad configurations. Through this process, an SoP array on an organic substrate with a pitch of 130 ${\mu}m$ is, successfully, formed.

  • https://doi.org/10.6117/kmeps.2013.20.4.065 인용 PDF KSCI

ECC 기반의 공개키 보안 프로토콜을 지원하는 보안 SoC (A Security SoC supporting ECC based Public-Key Security Protocols)

  • 김동성;신경욱
    • 한국정보통신학회논문지
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    • 제24권11호
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    • pp.1470-1476
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    • 2020

  • 모바일 장치와 IoT의 보안 프로토콜 구현에 적합한 경량 보안 SoC 설계에 대해 기술한다. Cortex-M0을 CPU로 사용하는 보안 SoC에는 타원곡선 암호 (elliptic curve cryptography) 코어, SHA3 해시 코어, ARIA-AES 블록 암호 코어 및 무작위 난수 생성기 (TRNG) 코어 등의 하드웨어 크립토 엔진들이 내장되어 있다. 핵심 연산장치인 ECC 코어는 SEC2에 정의된 20개의 소수체와 이진체 타원곡선을 지원하며, 부분곱 생성 및 가산 연산과 모듈러 축약 연산이 서브 파이프라인 방식으로 동작하는 워드 기반 몽고메리 곱셈기를 기반으로 설계되었다. 보안 SoC를 Cyclone-5 FPGA 디바이스에 구현하고 타원곡선 디지털 서명 프로토콜의 H/W-S/W 통합 검증을 하였다. 65-nm CMOS 셀 라이브러리로 합성된 보안 SoC는 193,312 등가 게이트와 84 kbyte의 메모리로 구현되었다.

  • https://doi.org/10.6109/jkiice.2020.24.11.1470 인용 PDF KSCI