Query: QFN process flow

Candidate papers:

abstract: Package thinning, down scaling, and miniaturization are common interests among semiconductor industries, with each manufacturing site having different approach and technical directions in providing novelties in their products. The paper offers an innovative design of manufacturing flow to reduce the semiconductor package height of a Quad Flat No leads (QFN) device through the application of a specialized package grinding process. The process would significantly reduce the carrier thickness for the overall package height configuration of QFN. Through this integration, the common assembly barriers and defects related in producing thin devices are eliminated, thus thinner version manufacturing becomes more simplified and efficient.
author_names: Rennier S Rodriguez

Frederick Ray I Gomez
title: Incorporating Package Grinding Process for QFN Thin Device Manufacturing
year: 2020

abstract: This research studied about an epoxy molding compound (EMC) floor life to reliability performance of integrated circuit (IC) package. Molding is the process for protecting the die of IC package form mechanical and chemical reaction from external environment by shaping EMC. From normal manufacturing process, the EMC is stored in the frozen at 5oC and left at around room temperature for aging time or floor life before molding process. The EMC floor life effect to its properties and reliability performance of IC package. Therefore, this work interested in varied the floor life of EMC before molding process to analyze properties of EMC such as spiral flow length, gelation time, and viscosity. In experiment, the floor life of EMC was varied to check the effect of its property to reliability performance. The EMC floor life were varied from 0 hours to 60 hours with a step of 12 hours and observed wire sweep, incomplete EMC, and delamination inside the packages for 3x3, 5x5 and 8x8 mm2 of QFN packages. The evaluation showed about clearly effect of EMC floor life to IC packaging reliability. EMC floor life is not any concern for EMC property, moldabilty, and reliability from 0 hours to 48 hours for molding process of 3x3,5x5 and 8x8 mm2 QFN packaging manufacturing
author_names: Udom Peanpunga

Kessararat Ugsornrat

Panakamol Thorlor

Chalermsak Sumithpibul
title: The Effect of Epoxy Molding Compound Floor Life to Reliability Performance and mold ability for QFN Package
year: 2017

abstract: The development of solutions for high power packaging systems requires the use of a die attach material that has high thermal conductivity and low electrical resistance. However, solder paste, one of which meets this design requirement, is often affected by solder voids that form during the reflow process. By using a 3 factor full factorial design of experiment, this study looks into the effects of reflow profile, nitrogen flow rate, and leadframe type (A and B) on single and cumulative voids produced during the reflow process. Also, the effect of the location of specific nitrogen vents in the machine with respect to the package during reflow processing will be discussed. Analysis of data collected shows that use of higher N2 flow rate, leadframe type A, and reflow profile with higher time above liquidus and soak time reduces both single and cumulative void dppm by more than 95% This is attributed to lower oxidation and increased flux outgassing during solder reflow.
author_names: Ariel Jan V Sadural

Laura May Antoinette Clemente
title: Voiding reduction and leadframe interactions in high lead solder die attach for QFN applications
venue: 2017 International Conference on Electronics Packaging (ICEP)
year: 2017

abstract: A quad flat no lead (QFN) package delamination improvement and its related lead frame (LF) copper oxidation effect were studied. Pudding mold adhesion testing method was utilized to determine the epoxy molding compound (EMC)/LF interfacial adhesion performance, chemical composition change including cupric oxide (CuO, Cu+ and cuprous oxide (Cu2O, Cu+ on LF surface oxidation structure was identified by Auger electron spectroscopy (AES) Experimental results have shown that higher CuO/Cu2O ratio (Cu+/Cu+ 1) have a good adhesion characterization for different oxidizing observation, moreover, AES depth profile analysis have supported that the demonstration much CuO content to reduction is verified an important adhesion improvement after plasma clean process. Back end plasma clean conditions such as plasma time, slot/un lot magazine type, and H2/Ar mixing gas flow rate in a QFN package production for enhancing adhesion characterization were studied, moreover, a package delamination improvement was obtained by plasma clean conditions tuning.
author_names: M F Shu

Koduck Chen

Bret Yang

Webber Liu

Yi-Hsiu Tseng
title: Lead frames copper oxidation effect for a QFN package delamination improvement
venue: 2016 6th Electronic System Integration Technology Conference (ESTC)
year: 2016

abstract: Automotive IC demand is expected to grow tremendously at CAGR of 7% over the next few years. In general automotive devices can be packaged into commonly used packaging solution like SOIC, SOP, QFN, except a few automotive products may require custom packaging solution. This paper discuss the QFN packaging solution for automotive IC from the perspective of package outline design, material selection, process flow, manufacturing system control and reliability assessment. It also covers special topics of research on side wall plating and packaging design and process consideration for more stringent "under the hood" grade 0 automotive products.
author_names: Tan Boo Wei

Lee Yoke Foo

Niu You Hua
title: Automotive QFN packaging solution
venue: 2016 China Semiconductor Technology International Conference (CSTIC)
year: 2016

abstract: High end test handler with high efficiency is required in domestic.Through consulting many documents and researching test handler using turntable of import carefully,system design of TX900 quad flat no lead package test handler was drawn up.The work principle of TX900 QFN test handler was discussed.Running process of the machine was described.The system structure model was built with modular design method.The structure design of all parts was illustrated in detail.The structure of electronic control and design of control software were introduced.The flow chart of control program was presented.At last key technologies and solutions of the machine were discussed.The machine is efficient,compatible and extensible.The whole system design lays a foundation for the realization of the QFN test handler using turntable.
author_names: Cao Pan-jiang
title: System design of QFN test handler using turntable
year: 2010

abstract: The chip embedding technology achieved significant progress the last years. After various research activities the main focus is today on industrialisation and implementation of new business models. In the project HERMES European partners from industry and research aim to bring embedding technology based on low cost PCB /Printed Circuit Board) processes to a market ready product flow, demonstrated by automotive, power electronics and telecommunication applications. The research part of the project aims to overcome current limitations and to achieve even higher levels of miniaturisation. This paper will describe the embedding process flow and will discuss the process steps in detail. Three devices realised, a 2 chip module, a 3D System in Package and a QFN (Quad Flat No Lead) package will be described and discussed. Especially the realisation of the QFN is a strong challenge for today's machine capabilities, since it contains a chip with a pitch of 100 um.
author_names: Andreas Ostmann

Dionysios Manessis

Lars Boettcher

Stefan Karaszkiewicz

Herbert Reichl
title: Realisation of embedded chip QFN packages technological challenges and achievements
venue: 2009 European Microelectronics and Packaging Conference
year: 2009

abstract: Miniaturized package with thinner die requirement like Quad Flat No Lead (QFN) has led to new challenges for conventional die attach paste materials and dicing process. Die attach film (DAF) is seem to be the most potential candidate to replace the conventional die attach paste for QFN stacked die. DAF is able to replace epoxy paste in stacked packages in producing good paste bleed control, zero creeping effect and constant bond line thickness (BLT) Dicing die attach film (DDAF) will be used in this study; the laminated DDAF wafer will be diced together during wafer dicing. Laminated wafer will be cut by using step cut method. In dicing DDAF, parameter such as spindle rotation, feed speed, water flow and blade grit size will be considered. However, dicing DDAF laminated wafer is not as simple as the bare silicon wafer. Due to this reason, this paper will reveal the DDAF dicing response. Dicing responses like lateral crack, whisker formation and sidewall effect will be observed. The result shows that step cutting process gives the common dicing effect which is still in the accepted limit. In addition, the implementation of controlling dicing process parameter is crucial to obtain good dicing results.
author_names: Samihah Abdullah

S M Yusof

Azman Jalar

Mohamad Faizal Abdullah

Zalina Abdul Aziz

Ruslizam Daud
title: STEP CUT FOR DICING LAMINATED WAFER IN A QFN PACKAGE
year: 2008

abstract: Quad Flat No Lead Package (QFN) with "Super Thin" package height of 0.3 to 0.4 mm (package profile height sub code "X2" per Jedec Standard) is designed with limited vertical space for wire loop height. Typical package construction consists of leadframe thickness, chip and chip attach adhesive thickness, mold (encapsulation) thickness left only 75 to 100 um (3 to 4 mils) space between chip surface and package surface which is available for wire bonding Therefore wire bonding loop height in QFN X2 package are typically controlled within less than 100um (4mils) as measured from chip surface to highest point of wire loop Typically there are 3 areas to consider when developing gold wire bond techniques to achieve low loop height: 1. Stress level at the heat affected zone near wire exit above ball (1st bonds) 2. Consistency of wire loop height across all wires within same package. 3. Resistance to mold flow sweeping during molding (encapsulation process) There are two common wire bond techniques available to achieve wire loop height less than 100um (4mils) bond stitch on ball (BSOB) and ultra low loop (ULL) forward bonding. This paper discusses the comparative performance and limitations of both wire bond techniques
author_names: Tan Boo Wei

Wang Lei

Ken Niu

Lu Hai Long
title: Application Of Ultra Low Loop gold wire bonding technique in Super Thin (Jedec Package Profile Height Sub Code "X2" Quad Flat No Lead Package (QFN)
venue: 2008 33rd IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)
year: 2008

abstract: This paper elaborates on the EMC leadframe interfacial delamination in QFN package. The study was conducted to check each factor and process which contributes to the package delamination. A list of the possible process/factor and their impact on the package interfacial delamination were first determined through brainstorming. Fractional factorial screening experiment was then conducted to determine the vital few factors in the current process flow from the trivial many by incorporating the blocking concept on material batch to batch and machine to machine variation. The screening experiment shows the metal finishing process is the major contributor for delamination. Further each cell in metal finishing process was studied and step by step root cause identification was done. Statistical Analysis was used to determine each affecting factor for delamination. This report discusses the detail DOE to identify the root cause for interfacial delamination.
author_names: Teo Soon Tong

J Sharath Kumar

M M D Kanan
title: A Study and Investigation on Processes Inducing Delamination in QFN Package Using Statistical Analysis
venue: 2006 Thirty First IEEE/CPMT International Electronics Manufacturing Technology Symposium
year: 2006