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BGA Reflow Profile

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BGA Reflow Profile - Oct 30, 2007 by aj  

BGA Reflow Profile - Oct 30, 2007 by wayne  

BGA Reflow Profile - Oct 30, 2007 by Doug Philbrick  

BGA Reflow Profile - Oct 31, 2007 by aj  

BGA Reflow Profile - Nov 01, 2007 by davef  

BGA Reflow Profile - Nov 02, 2007 by


aj

#52231

BGA Reflow Profile | 30 October, 2007

Hi All,

I would appreciate some advise with regard to Leadfree settings for a 5 zone reflow oven.

I have a 35mm square BGA 672 pin on board. I am struggling to get the Delta T down to 2 degrees C . I have 5 Thermocuples drilled up from the bottom and glued into position ( impossible to solder ). One at each corner and 1 in the center.

The 2 leading TC reach Liquidus Temp roughly 3-5 seconds before the trailing TCs.

Peak Temp is within 2-3 degrees C.

Coming out of the Liquidus Zone the Trailig TCs are still in reflow for again approx: 5 secs after the leading TCs.

Settings - Speed 18 inches Per min. 160175215225270

Any replies appreciated.

aj

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#52232

BGA Reflow Profile | 30 October, 2007

how many layer board is it? what kinda temperatures is your oven currently hitting. In our reflow oven I have been using a profile that is the same for the top and bottom at zone 1 111C zone 2 at 164C zone 3 at 161C zone 4 at 208C and zone 5 at 253C. and 15 inches/minute. This is looking on our boards with NC254 (no-clean) paste. The 3rd zone being lower is because of the bleed over from the next zone, I needed to put it lower to maintain a good soak time. This profile I descrbed was used on a board containing 5 BGA's and it is a six layer board with lots of copper. Good luck!

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#52234

BGA Reflow Profile | 30 October, 2007

Wayne

I am curious what your heated length is on your oven.

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aj

#52236

BGA Reflow Profile | 31 October, 2007

Hi,

My oven has 5 zones each 12 inches in length , giving a total of 70 inches Heating Zone in total.

I am working with a 6 layer PCB ,ENIG Finish.

I am using Alpha OM338T no-clean Solder Paste.

I am working to a cycle time of 4 to 4.5mins RTS profile.

aj...

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#52257

BGA Reflow Profile | 1 November, 2007

AJ -

Why so stringent on your 2�C Delta T? You say your peaks are within 2�C - 3�C of each other within the device.

Reason I'm asking. With a 5-zone oven, it is very difficult to achieve that. With more zones, you can put a little "knee" or soak zone to let the thermal gradients stabalize before your reflow zone.

Is someone asking the impossible of you?

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#52270

BGA Reflow Profile | 1 November, 2007

How does the delta T on the board relate to the delta T on the component?

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aj

#52275

BGA Reflow Profile | 2 November, 2007

Hi all,

Thanks for the replies so far.

To make things clearer.

BGA is 35mm square.

Leading edge of BGA hits 217 and then trailing edge hits 217 5 seconds later. So leading edge is reflowing when the trailing end is not.

Coming out of the reflow zone - again the leading edge is out of reflow i.e. below 217 a good 6 seconds while the trailing end is still in reflow.

My worry is BGA tilt.

We have had a small occurence of Tilt in the past but we have just completed a batch of 600 and no issues.

aj...

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