In this paper we will review a wide range of plastic encased no-lead package configurations, industry package standards, and terminal design variations as well as defining the criteria for land pattern design and solder paste stencil development and assembly process methodologies detailed in the new IPC-7093 standard, “Design and Assembly Proces...

Throughout this document the word “BTC” can mean all types and forms of bottom only termination components intended for surface-mounting. This includes such industry descriptive nomenclature as QFN, DFN, SON, LGA, MLP, and MLF, which utilize surface to surface interconnections.

QFN/DFN 為無引腳設計,一般很難從其外觀的焊錫點來判斷其焊錫性是否良好,目前 QFN/DFN 的焊錫檢查主要用電測 (In-Circuit-Test 、 Function Test) 來偵測其功能,一般也會佐以光學儀器或 X-ray 來檢查焊錫的開、短路不良現象。 功能測試正常, 以顯微鏡檢驗結果引腳側面未爬錫,以X-Ray檢驗結果引腳下方有錫。 QFN/DFN 封裝側面的引腳是 Leaf frame( 導線架)的切斷面,並無電鍍處理,所以很難吃錫, IPC-A-610 並未定義側面引腳要吃錫( 規範中Note 5 說明上圖H 的部位不需吃錫), …

In this study, various designs of thermal pads, stencil patterns, and reflow profiles are evaluated in order to identify the optimal condition for minimizing the voiding. The effect of each variable on voiding is analyzed and presented in the paper.

qfn，方形扁平无引脚封装，是表面贴装型封装之一。 按照ipc-a-610的标准qfn侧边焊盘爬锡要求，分为三个等级： 1级为qfn焊盘底部填充锡润湿明显； 2级为侧边焊盘高度的25%； 3级标准为侧边焊盘高度的50%；

2020年7月27日 · 按照ipc-a-610的标准qfn侧边焊盘爬锡要求，分为三个等级如下： 1级为QFN焊盘底部填充锡润湿明显； 2级为侧边焊盘高度的25%；

QFN (Quad Flat No leads，四方平面無引腳封裝)在現今電子業界的IC封裝當中似乎有越來越普遍的趨勢，QFN的優點是體積小，足以媲美CSP(Chip Scale Package)封裝，而且成本也相對便宜，IC的生產製程良率也蠻高的，還能為高速和電源管理電路提供較佳的共面性以及散熱能力 ...

Successful implementation of QFN-style packages, including QFNs and DQFNs, requires special consideration for PCB Footprint design, PCB layout, and solder paste stencil design. This application note describes these important consid-erations. The following guidelines are based on Microchip’s experience and knowledge, and may be accepted or rejected.

2012年12月13日 · qfn的焊盘设计主要包含以下三个方面：周边引脚的焊盘设计、中间热焊盘及过孔的设计和对pcb阻焊层结构的考虑。 1、周边引脚的焊盘设计. 对于qfn封装，pcb的焊盘可采用与全引脚封装一样的设计，周边引脚的焊盘设计尺寸如图2所示。

2015年7月14日 · QFN and DFN packages are plastic encapsulated lead-frame-based packages, which are near Chip Scale Package (CSP) with a low profile (<1.0 mm). This pack-age type uses perimeter lands/pins on the bottom of the package to provide electrical contacts to the PCB. Perimeter pins can be arranged in dual-in-line (DFN) or quad (QFN) configuration.