PCB Universe FAQs

FAQ

Data File Standards
Format	Gerber RS-274X is preferred although we can accept RS-274D and ODB++ formats. We do not accept board layout files in AutoCAD, Eagle or other software specific formats.
Drill File	Excellon Drill File (a.k.a. ASCII or CNC Drill) - Including tool size list
View	We assume all Gerber layers are viewed from top side. This means your bottom layers will appear 'backward'. For example, your bottom side silkscreen should be 'wrong reading' or backwards, as if in a mirror, since you are viewing it from the top side, not the bottom.
Fab Print	We prefer all orders to contain a detailed fab print specifying dimensions, board thickness, material type, copper weight, dielectric stackup, qty of holes, whether holes are plated or not, layer stack order….etc. If a print or other instructions are not provided, we will build per PCB Universe Rigid PCB Standards.
Alternative File Types	If your Gerbers do not contain a fab print, we can accept prints in other popular formats such as PDF, DXF, DWG, TXT … etc.
Delivery	For ease of delivery and to ensure no files are lost, please place all design files, fab notes and other files regarding your order, into a single .zip file. If ordering online, please upload your file through the online order system so it can be associated and tracked with your order.

Final Finish	Cost	RoHS	Fine Pitch Use	Flatness	High Speed	Rework Cycles	Shelf Life	Solder Joint	Solderability	Wire Bonding
Final Finishes 101
There are many factors to consider when selecting a final finish for your printed circuit board. Below is a consolidated list of popular finishes and their general characteristics.
Tin/Lead Solder (HASL)	Lowest	No	No	Bad	No	Few	12 months	Excellent	Excellent	No
Lead Free Solder (HASL)	Lowest	Yes	No	Fair	No	Few	12 months	Good	Good	No
OSP (Organic Solder Preservative)	Low	Yes	Yes	Excellent	No	None	9-12 months	Good	Good	Yes
Immersion/White Tin	Low	Yes	No	Excellent	No	None	9-12 months	Good	Good	No
Immersion Silver	Medium	Yes	Yes	Excellent	Yes	Many	9-12 months	Good	Very Good	No
Immersion Gold (ENIG) Electroless Nickel Gold	Medium	Yes	Yes	Excellent	No	Few	12 months	Good	Good	No
Hard/Deep Gold	High	Yes	No	Bad	No	None	12 months	Bad	Good	No
Wirebondable/Soft Gold	Very High	Yes	Yes	Good	No	None	12 months	Bad	Good	Yes

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Tin/Lead Solder (HASL)	The PCB is dipped into a solder pot and air knives remove the excess solder from the surface of the board. The typical chemical composition of this finish is approximately 63% Tin and 37% Lead. Historically this has been the accepted industry standard finish but tighter designs and lead free legislation may soon bring this finish to an end for most purposes. Only military, medical and select few other devices that require high dependability are currently exempt from RoHS legislation.
Pros	Lowest cost and remains solderable through many cycles. Relatively low temperature reflow point.
Cons	Not recommended for lead pitches less than 0.64mm (.025 inch) due to solder bridging and uneven thickness. Lead is a known cause of many illnesses, more stringent environmental (RoHS lead free) legislature may eventually eliminate this plating option.
Lead Free Solder (HASL)	The PCB is dipped into a solder pot and air knives remove the excess solder from the surface of the board. Various chemistries exist for Lead Free Solder but most rely on a 99% Tin composition with various trace elements depending on the manufacturers recipe. While it is flatter than its lead counterpart, Lead Free Solder is still not recommended for fine pitch applications.
Pros	Lowest cost and remains solderable through many cycles.
Cons	Not recommended for lead pitches less than 0.64mm (.025 inch) due to solder bridging and uneven thickness. Tin Whiskering is also a concern with tightly spaced features. http://nepp.nasa.gov/whisker/background/index.htm#q1
OSP (Organic Solder Preservative)	A very thin finish. Its only purpose is to protect the bare copper from oxidation since it dissipates after soldering. Assemblers need to use a different type of flux and cannot use as many heating cycles as with other finishes.
Pros	Low cost, flat surface, good solderability and can be wire bonded.
Cons	Significant changes to assembly process make it unpopular with most assemblers. Special handling required since finger prints can easily erode the OSP finish exposing the copper to oxidation.
Immersion / White Tin	Due to the many other superior alternatives available today, this finish is seldom used.
Pros	Good solderability, flat surface, low cost.
Cons	Subject to Tin Whiskering and limited rework capability. Solutions used in manufacturing are suspected carcinogens and pose potential health threats.
Immersion Silver	Unlike gold finishes which use a layer of nickel to prevent the base copper from migrating into the metal, silver does not require this process. Silver is applied directly onto the bare copper. Silver is quickly gaining in popularity as a preferred RoHS finish. ENIG is still #1 but time will tell.
Pros	Good solderability, assemblers like it since it can be worked like HASL. During the solder process the silver is dissolved into the joint providing very good connections, ideal for BGAs.
Cons	Higher cost than solder but less expensive than ENIG. Tarnishes relatively easily so keep them in a cool, dark place in their original packaging until ready to assemble.
Immersion Gold (ENIG) Electroless Nickel Gold	ENIG stands for Electroless Nickel Immersion Gold. Approximately 100-150µ" of nickel is applied directly to the bare copper on the PCB. 2-5µ" of gold are then applied on top of the nickel via a chemical process. Because the gold bonds to the nickel by replacing the outer nickel molecules, the resulting finish is extremely flat and cannot be plated any thicker than approximately 5-6µ".
Pros	Excellent solderability, flat surface, long shelf life, multiple reflows, will not tarnish easily, precious metal electrical contact surface, mini nickel rivet which strengthens hole walls, and the nickel barrier also protects the barrels from copper dissolution during wave solder and rework.
Cons	Higher cost, nickel layer is fairly brittle and has been noted to break during mechanical stress. This is known as "black pad" or "mudflat cracks".
Hard / Deep Gold	Like all gold finishes, 100-200µ" of nickel is used as a barrier to prevent the copper from migrating into the gold. Because this finish is plated using electricity rather than chemically, the surface is relatively rough. There are hardeners added to the chemistry making the finish very durable. It is generally used for edge fingers or keypad based applications where high durability is desired. Typical gold thickness for this finish range between 7 to 50µ".
Pros	Durability and long shelf life.
Cons	High cost, no rework capability and poor coplanarity (flatness).
Wirebondable / Soft Gold	Like Hard/Deep Gold, this process is electroplated except this is 99.99% pure gold. Due to its very high cost, it is typically used only for wirebonding applications. Typical gold thickness is between 30-100µ" over 150-200µ" of nickel. Cost varies significantly depending on the desired gold thickness.
Pros	Long shelf life, solderability and wirebondable.
Cons	Very high cost and no rework capability.

Standard Specifications (Rigid Boards)
PCB Universe Rigid PCB Standards
To avoid miscommunication, we prefer all data packages to contain a complete fab print detailing all aspects of your PCB fabrication either within your Gerber data or in another commonly used format such as a PDF, DWG or even a simple TXT file.
We realize this is not always convenient or possible for all of our customers so please be aware that if your data is incomplete we will build to the following standard specifications. It is your responsibility to review the quoted/ordered specifications and verify they are acceptable for your design.
* Below is a list of our rigid PCB manufacturing assumptions if your data is incomplete. We have many other capabilities, these are simply our standards.
Material Type	FR4 (135-140°C Tg) 94V-0 Flame Rating
Finished Thickness	.062"
Rout Type	Individually routed
Array/Panel	If you require your board to be panelized into an array for automated assembly, we will be glad to step and repeat your 1-up design for you at no extra charge. We assume .4" rails on all 4 sides of the array whether it be scored or tab-routed. We will score where possible and tab-rout (rout and retain) where it is not. Many assemblers have guidelines as to how they prefer arrays to be constructed. Check with your assembler if they have size limitations or preferences regarding rail placement, tooling holes and fiducials.
Finished Plating	Lead Solder
Copper Weight	1oz (finished weight, outer and inner)
Drill	All holes assumed plated thru (PTH). If there is no copper pad surrounding the hole on the top and bottom layers or the pads are the same size as the drill and no apparent electrical purpose, will assume non-plated thru hole (NPTH).
Slots	Slots are assumed to be non-plated thru unless there is a copper pad surrounding the slot on both the top and bottom layers.
Soldermask	We will use your soldermask files if included in your data. If your design is all thru-hole and we receive only 1 mask file, will assume it is to be used on both sides. Soldermask type will be LPI (Liquid Photo Imageable).
Soldermask Color	Green
Silkscreen	We will use all silkscreen files included in your data. Any legend that covers pads or annular rings will be clipped to ensure proper final finish adhesion.
Silkscreen Color	White
Gold Fingers	If your design appears to have an edge connector we will assume 20µ" hard gold over 100-150µ" nickel plating and beveled edge.
Dielectric Thickness	We will use one of our standard dielectric stacks based on your design and materials we have on hand.
Impedance	We assume there are no impedance requirements unless specifically stated.
RoHS	If RoHS compliancy is requested, we will build with Lead Free Solder and FR4 (135-140°C Tg) material. All of our final finishes are RoHS compliant EXCEPT Lead Solder. All board laminates we use are also RoHS compliant. We assume our standard FR4 (135-140°C Tg) material is sufficient for your RoHS needs. Use of a hi-temp laminate must be specified. RoHS compliancy is not an indication of special laminate temperature requirements or final finish. Consult with your PCB assembler if you are unsure what final finish or laminate they require for their RoHS process.
ITAR	We assume all designs are not ITAR controlled.
Board Thickness Tolerance	±10% or ±5 mil, whichever is greater
Dimensional Tolerance	±10 mils
Inspection Criteria	IPC Class II

Policies
Order Cut-Off Time	Orders may be placed on our website 24 hours a day, 365 days a year. Depending on the day of the week and/or time of day, your order may not be processed until the next business day. Orders placed Monday-Friday before 9pm(EST)/6pm(PST), will be counted as being entered that day. Orders placed over the weekend, on a holiday or after 9pm(EST)/6PM(PST) will be processed the next business day.
Calculating Lead Time	Our lead times are calculated in business days. The day an order is processed is day zero, (see order cut-off time). If it is 3pm on Wednesday, a 4 day turn will ship no later than the next Tuesday. (Assuming no holidays or delays from incomplete or unclear data).
	Wed = 0	Thu = 1	Fri = 2	Mon = 3	Tue = 4 (order ships)
After hours Contact	As with any custom fabrication, questions can arise if there is any missing or unclear data. We never want to delay the shipment of your order so please provide us with an after hours contact so we can address any questions as soon as possible. Turn times do not begin until your order clears engineering review.
Electrical Test Policy	We electrically test every bare PCB we manufacture. Please be aware that some shorts or opens may not be present or detectable until after the heat cycle of the assembly process.
Electrical Test Types	Depending on the design, we may use a flying probe or clamshell test fixture at our discretion. For designs with Controlled Impedance requirements, we will test to verify your target impedance has been achieved and list the results on your inspection report. Upon request we can also perform a high voltage test.
Warranty	We will gladly replace or credit any boards that are found to be defective within 60 days of the original shipment that we find to be defective in materials, workmanship or order accuracy. We will not be held accountable for monetary losses including but not limited to; missed deadlines, components, labor or other damages.

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FAQ

Data File Standards

Final Finishes 101

PCB Universe Rigid PCB Standards

Policies

Privacy Policy