Hi Ramon,
We end up with a 24 mils squard pads with 14 mils gap
in between. Stencil opening looks like this.
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Ted
--- "Dehoyos, Ramon" <[log in to unmask]> wrote:
> Hi Ted:
> What was your particular land design ( shape
> of the lands ) for the 0402s that work well for you?
> Regards,
> Ramon
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of
> Ted Kong
> Sent: Wednesday, September 29, 2004 12:17 PM
> To: [log in to unmask]
> Subject: Re: [TN] ENIG vs. HASL plating with 0.5 mm
> pitch QFN components
>
>
> Hi, Joe,
>
> one of our design has 0402 and QFNs on the board and
> we use HASL with 4 mils stencils. Our factory did
> not
> report any issue. One thing to keep in mind is that
> you must have a good pad design for 0402 land
> pattern
> to prevent insufficient solder or tombstoning.
>
>
> Ted
> --- "Wenger, George M." <[log in to unmask]>
> wrote:
>
> > Paul,
> >
> > I didn't make any comment about planarity or
> > indicate that HASL couldn't be controlled and used
> > for 0.5mm pitch because there are lots of
> companies
> > using HASL for 0.5mm pitch. The reason I wouldn't
> > recommend HASL is because of the pending RoHS/WEEE
> > directives.
> >
> > Regards,
> > George
> >
> > George M. Wenger (908)-546-4531
> > Reliability / FMA Engineer
> > Base Station and Subsystems Group
> > Andrew Corporation, 40 Technology Drive, Warren,
> NJ
> > 07059
> > [log in to unmask]
> >
> >
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]]On Behalf Of
> > Paul Edwards
> > Sent: Monday, September 27, 2004 4:34 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] ENIG vs. HASL plating with 0.5
> mm
> > pitch QFN components
> >
> >
> > Joe,
> >
> > I disagree with Paul and George...
> >
> > The planarity issue with HASL on .5mm pitch parts
> is
> > over blown.
> > A good PCB fabricator can control HASL variations.
> >
> > HASL increases the volume of solder in the lap
> joint
> > and increases and
> > lowers the joint's bulk interface intermetallics.
> >
> >
> > Paul
> >
> > Paul Edwards
> > Process Engineering
> > [log in to unmask]
> > Tel: 408-433-4700
> > FAX: 408-433-9988
> > Surface Art Engineering
> > 81Bonaventura Dr.
> > San Jose, CA 95134
> > DUNS: 944740570
> > CAGE/NCAGE: 1XZ48
> >
> > -----Original Message-----
> > From: Black, Paul [mailto:[log in to unmask]]
> > Sent: Monday, September 27, 2004 11:40 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] ENIG vs. HASL plating with 0.5
> mm
> > pitch QFN components
> >
> > Joe,
> >
> > I would agree with George on both counts. In any
> > case, I wouldn't choose
> > HASL. It doesn't deposit evenly. In the case of
> your
> > fine pitch and small
> > components, you could end up with reliability
> > issues.
> >
> > Thank you,
> > Paul Black
> > Manufacturing Engineer
> > Kronos
> > E-mail: [log in to unmask]
> > Voice: (978) 947-1520
> > Fax: (978) 244-0568
> > www.kronos.com
> > Improving the Performance of People and
> Business(tm)
> >
> >
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]]On Behalf Of
> > Wenger, George M.
> > Sent: Monday, September 27, 2004 1:21 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] ENIG vs. HASL plating with 0.5
> mm
> > pitch QFN components
> >
> >
> > Joe,
> >
> > Were you asked to recommend the type of pwb
> plating
> > that is best for your
> > simple board or were you only given two choices to
> > pick from? If I had to
> > pick from the two choices I'd pick ENIG. If I had
> > to make a recommendation
> > I wouldn't recommend either. My preference would
> be
> > immersion silver.
> >
> > Regards,
> > George
> >
> > George M. Wenger (908)-546-4531
> > Reliability / FMA Engineer
> > Base Station and Subsystems Group
> > Andrew Corporation, 40 Technology Drive, Warren,
> NJ
> > 07059
> > [log in to unmask]
> >
> >
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]]On Behalf Of
> > Macko, Joe @ IEC
> > Sent: Monday, September 27, 2004 1:08 PM
> > To: [log in to unmask]
> > Subject: [TN] ENIG vs. HASL plating with 0.5 mm
> > pitch QFN components
> >
> >
> > Fellow techs,
> >
> > I have been asked to recommend the type of pwb
> > plating that is best for a
> > simple board with only a few components. The
> finest
> > pitch component is a
> > QFN, 64 pads, 0.5 mm pitch. There are some 0402
> > resistors and capacitors as
> > well.
> >
> > My 2 choices are HASL or ENIG. Would someone
> please
> > comment on which is
> > best for 0402 and 0.5 mm QFN type components.
> >
> > Thanks in advance.
> > joe
> >
> >
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