PCB - Printed Circuit Boards

Materials

• FR-4 Tg 140 degree

• FR-4 High Tg 160 degree

• FR-4 High Tg 180 degree

• Modified Epoxies

• Polyimide

• Cyanate Ester (Low dk/Low Loss)

• PTFE or equivalents

• Alternative HDI Dielectrics

• Halogen Free Material

• Rogers 4350

• Getek

• Nelco 6000

• BT

• Taconic

• Roger 4K Series

• Roger 3010

• Risholite

• GIL

Surface Finish

SA Electronics offers the following surface finishes for PCB fabrication to meet a variety of complex needs:

Immersion Silver — RoHS compliant finish available on all product lines. This "no additional cost" coating that provides a very planar surface and a very reliable solder joint. While this finish is ideal for prototyping as well as larger lot sizes, this coating is more susceptible to temperature, humidity as well as handling. As a result, care should be taken when storing or handling these PCBs. Thickness of silver is 4 to 20 micro inches.
OSP (Organic Solderability Preservative) - A transparent organic coating is deposited on features that are not covered with solder mask.
HASL — Tin-lead solder coating (Hot Air Solder Level). This time tested finish is available through all product lines and at no additional cost. Solder provides the most reliable solder joint and shelf life of the available surface finishes. However due to the thickness and application of this coating, it can be less planar and may not be an ideal choice for fine pitch components. Solder Thickness varies from 0.2 to 1.2 mils. This variation is due to board circuit density, aspect ratio. Solder consists of 63%/37% eutectic Tin/lead.
White Tin - Immersion tin is deposited on features not covered with Solder mask. Thickness is typically 30-40 micro inches.
Carbon Ink for Key pad application - A conductive carbon paste is applied on selective pads for contact purposes, e.g.. Keypads of calculators, etc.
ENIG — (Electroless Nickel / Immersion Gold) RoHS compliant finish provides a very planar surface, a very reliable solder joint and is very resistant to environmental storage conditions, handling etc. ENIG provides a great deal of flexibility of applications and is ideally suited for PCBs of many design needs. Typically 150-200 micro inches of nickel is deposited, and 5-10 micro inches of Hard gold. Gold flash is applied to features after pattern Copper plating.
Gold Fingers — Ideal surface finish for a wear application such as an insertion connector. Provides a very planar surface that is resistant to wear from repeated insertions. Gold fingers can be ordered in conjunction with the other surface finishes as well, to provide the needed solderable surface finish, as well as the wear protection needed, all on one circuit board.
Wire Bondable Soft Gold - Electrolytic soft gold is plated on features that require bondable gold for wire bonding application. Depending on the type of wire bonding used, the thickness of gold varies from 20 to 50 micro inches. Nickel thickness is between 150 to 250 micro inches.

Technologies

Specification Tables....click here....

Testing Parameters

• Net List TestingIPC-D-356

• Voltage100 Volts

• Continuity Resistance10 ohms

• Isolation resistance10 MOhms

Impedance

Type Standard Advanced

• Single-ended % ±10 ± 5

• Differential, Edge-coupled % ±10 ± 5

• Differential, Broadside-Coupled % ±10 ± 10

Flex Capabilities

Material selection, process tolerances, manufacturing logistics, and your flex supplier all play an important role in producing a cost-effective and reliable flex circuit design.
At SA Electronics Inc., we can assist you in your Design For Manufacturing (DFM) efforts to help minimize overall program costs. Listed are standard materials and capabilities. List Here...

Laser-Drill Micro-Vias

HDI and Micro-Vias

As PCBs continue to decrease in size and increase in complexity, your PCB fabricator has to keep up. As a designer, you certainly understand that old processes are revised and new ones are added, including those needed for High Density Interconnect (HDI).

SA Electronics Inc. is always working to stay ahead of the game!
HDI is one of SA Electronics's specialties. HDI requires more than fine lines in the foil pattern; it also requires Sequential Build-Up (SBU), and laser-drilled Micro-Vias.

Sequential Build-Up

Multilayer technology using SBU involves the addition of one layer of dielectric and foil pattern at a time, allowing processing of HDI Micro-Vias before adding another layer.
These layers are added to the substrate in pairs, one layer on each side of the substrate, to balance the stresses to the substrate. For example, 1, 2, 3, etc. layers on each side of the substrate (N), or 1+N+1, 2+N+2, 3+N+3, etc.

Laser-Drilled Micro-Vias

Laser-drilled Micro-Vias reduce the space required by through-the-board vias. They are smaller in diameter, and because of this, more space can be devoted to circuit traces.
A Micro-Via links only one layer of foil to the next; layers above and below them are available for foil lines, further increasing overall circuit density.
As each layer of SBU is added, a laser drills a hole from the outer layer of foil, through the dielectric that was just laid down, to the next inner layer of foil. This hole is then plated and filled. If there is an additional layer of SBU, the Micro-Via becomes buried.
We fill the Micro-Vias with solid metal for stronger connections and to obtain better thermal management, increasing overall board reliability. Not all fabricators fill their Micro-Vias.
High density I/O components sometimes require Via-In-Pads (VIP) just to connect traces to all solder pads. When VIPs are used, filling the Micro-Via helps keep the pad smooth, allowing for a better reflow of solder.
Filling also allows the Micro-Vias to be stacked on top of each other to connect three or more layers of foil, further increasing density.

Inner Layer

Inner Layers are known as the internal layers of a multilayer PCB.
The laminate and dielectric thicknesses as well as the copper weights of inner layers are predefined for Quickturn/PCBexpress product .
The thickness and copper weight of these inner layers can be customized to meet your needs. The minimum manufacturable trace widths and spacing are based on the copper weight of the layer.
Inner layers sometimes employ a "copper pour" technique. Copper pour is commonly used to create a power plane or a ground plane. Another benefit of using a copper pour is to reduce the amount of chemistry (etchant) used during manufacturing as well as helping the layer to layer bonding process.
Inner layers may be transmitted for fabrication with either a positive polarity or a negative polarity. It is important that the polarity of the layer be noted during the ordering process in the absence of a polarity distinguishable feature (i.e. thermal connection).

Outer Layer

The outer layers are also known as the external copper layers of the PCB. Normally, the components are attached to the outer layers.
Outer layers begin with a copper foil that is then electroplated with copper to increase the thickness and add copper to the through-hole barrels. The copper weight of the outer layers is predefined (1/2 oz plated to approximately 1.0 oz). The finished copper thickness of these layers, however, can be customized to meet your needs.
Minimum manufacturable trace widths and spacing requirements are based on the pre-plate copper weight of the layer.

Soldermask

Soldermask is functionally the "mask layer" that defines the size and location of all of the solderable surfaces of a PCB. This layer allows the other conductors of the outer layers to remain isolated from solder during assembly processes.
Green soldermask has long been the industry standard color.
SA Electronics.Inc offers a variety of additional soldermask colors (blue, black, red and white) through Custom Quote to allow further customization to your PCB.

Silkscreen

Silkscreen (also known as legend or nomenclature) defines the text-based, human-readable information that one finds printed onto the surface of a circuit board. Silkscreen information can include component reference designators, company logos, component identifiers, switch settings, test points, other instructions, part numbers, version numbers, etc.

Traditionally, silkscreen has been applied using a traditional screen printing process. Increasingly, silkscreen is applied using a custom-built digital printer with an ink-jet technology.

Other colors (black or yellow) are available.

See silkscreen capabilities for the minimum line widths, character heights and widths, and registration tolerances.

Drill File

The NC (Numerical Control) Drill file defines hole locations, tool numbers and finished hole sizes (X&Y coordinates). For Low Volume all holes are treated like plated through holes. Holes intended to be non-plated will finish larger than the design file (+/- 0.005") indicates and we do not guarantee the holes will remain unplated (even a hole that has no external pad).

SA Electronics Inc. offers 2 choices of drill sizing for your PCB fabrication.

Maximum 23 Drill SizesStandard. There are a pre-set 23 drill sizes ranging from 0.0135” to 0.251”(finished).
Custom Drill Sizes: This selection will allow the finished hole size of the circuit board to match your design requirements. Drilled hole sizes available starting at 0.010”. The smallest drill size available is 0.0135".

Specified holes < 0.018" will be treated as vias, and drilled approximately the same size as specified. The smallest available bit is 0.0135". If your drill is smaller, it will be increased to this size.

Hole sizes > 0.250" will finish as non-plated.

Routing

The final step to complete your PCB order is to remove each board from the larger panel upon which it was fabricated. Depending on the method of assembly and the partner chosen for assembly, one of these three options will meet your needs.

During the manufacturing process, SA Electronics Inc. offers three options for routing:

Individual The board perimeter is routed to the outline and size provided. This outline must be a continuous route path using an 0.093” diameter router. For route paths that require smaller notches and arcs, with a router diameter down to 0.031.”
PalletizationCombine the boards into an array using tabs at the board edge or tabs with perf holes (optional). This option will space the boards approximately 0.1” apart. A standard (1/2") frame is added to the perimeter of the array. This selection can be helpful for boards being assembled by automated means.
V-ScoreCombine the boards into an array separated by only a score line for break apart after assembly.

Gold Tips

Fingers usually refer to the terminals on a card-edge connector. Gold fingers are gold-plated card-edge connectors.

Gold provides a good surface finish for a high-wear applications, such as an insertion connector. This is partly due to the fact that hardened gold provides a very planar surface that is resistant to wear from repeated insertions. For the manufacture of printed circuit boards, a bright hard gold with a mixture of nickel and/or cobalt is often used for card edge connector fingers.

Gold can be ordered in conjunction with all the other surface finishes available.

CopperWeights

Copper Weight is defined as the amount of copper present in one square foot of area. This parameter indicates the overall thickness of copper on the layer.

SA Electronics Inc. utilizes the following copper weights for PCB fabrication (pre plate). Weights measured in oz/ft2. The appropriate copper weight can be selected to fit the design requirement.

0.5 oz copper (~17.5µm thick or 0.7 mils) — Available on internal layers. Standard starting copper weight for external layers on product selected with 1 oz finished copper.
1 oz copper (~35µm thick or 1.4 mils) — Standard internal layer copper thickness 1.5 oz finished copper.
2 oz copper (70µm thick or 2.8 mils) — Available on internal layers as well as on 3 oz finished copper. Available on internal layers as well as on 3 oz finished copper.

Plating

Plating on a PCB refers to the electrochemical process by which a metal is deposited onto the surface of the circuit board, and inside the plated through-holes. The most common plated metal in PCB fabrication is copper. Copper plating serves two purposes, it increases the copper thickness of the surface pads and conductors as well as providing a robust copper connection from layer to layer through the plated through-holes.