HPL (High Power Lighting)

HPL is specifically formulated for high power lighting LED applications with demanding thermal performance requirements.

Dielectrics FAQs

Selection Characteristics Summary Product Family FAQ's

1).

Question: How does the cost of Thermal Clad compare to that of FR4?

Answer: The simple answer is: it doesn't! To make a true and useful cost comparison, one should compare the costs of FR-4:

plus heat sink
plus device mounting hardware (such as clip, screw or clamp)
plus interface (Sil-Pad)
plus the cost of manual assembly versus the Thermal Clad automated surface mount assembly.

Taking into consideration all relevant costs, Thermal Clad system is lower overall when comparing it to a traditional printed circuit board (PCB) and heat sink assembly.

2).

Question: How does the cost of Thermal Clad compare to that of DBC?

Answer: Again the costs have to be like for like. Unlike Thermal Clad, Direct Bonded Copper (DBC) always involves some method of mechanically attaching it to a heat sink. This is either a solder operation or a mechanical frame to secure the DBC. It is not possible to secure the DBC with mounting holes built into the delicate ceramic whereas Thermal Clad can support mounting holes, rivets, press-in fastners, etc. In simple terms, Thermal Clad can be worked like any metal sheet, even forming into a box-shape is possible. Taking into consideration all relevant costs, Thermal Clad system provides lower overall costs when comparing it to a DBC substrate and heat sink assembly.

3).

Question: Our company does not do surface mounting. Can we still use Thermal Clad?

Answer: Yes you can! Even if your company does not have the capability to assemble Thermal Clad, it is still possible to take advantage of Thermal Clad's high thermal performance and also remove the need for a number of clips and screws per power device. Thermal Clad can be used to solder all of your power devices in a row and create a sub-assembly. The device leads are formed, then "through-hole" mounted into your control PCB. Bergquist can offer names of sub-contract manufacturing assembly houses to build these assemblies.We call this system Thermal Clad-Power Rail.

4).

Question: Do I need an interface between Thermal Clad and any additional heat sink?

Answer: This depends on your application. For example, in thermally demanding applications, you will be concerned about transferring as much heat to the heat sink as possible. Bergquist Hi-Flow phase change material is often used in these applications to assure an intimate contact between the the Thermal Clad base to heat sink. Phase change material softens to a paste-like consistency and wets the surfaces when it reaches a threshold temperature. In addition to this, Thermal Clad can be formed in a slightly convex shape with respect to the base. When bolted down with mounting holes around the edge, the part is assured good contact with the heat sink.

5).

Question: Why does Bergquist offer copper-based as well as aluminum-based Thermal Clad?

Answer: There is a need for both. Depending on your application, either copper or aluminum may be the applicable solution. However, if your application demands heavy copper weights due to large current requirements or for mounting ceramic devices, then copper is recommended, or as copper foil thickness approaches 10% of the thickness of aluminum. The use of a copper base for Thermal Clad is especially suitable for bare die or large ceramic chip capacitors. In addition, copper does not have the CTE (coefficient of thermal expansion) mis-match issues that can be present with copper/aluminum substrates. See our "Selecting Base Material" section on the web and learn how you can select a thinner copper base for costs similar to thermally equivalent thicker aluminum.

6).

Question: What circuit finishes are available?

Answer: Any type of finish that can be applied to regular FR-4 can be applied to Thermal Clad as well. This traditionally ranges from Hot Air Solder Levelling (HASL) for the re-flow process and nickel-gold process for wire bonding and other finishes that are RoHS compliant. A solder mask is often used to keep parts clean and help with pattern recognition, it also contains the molten solder during the re-flow process.

7).

Question: Do I need to fix my power devices in place during re-flow to stop them from moving around?

Answer: This is not required. In most cases, if you design the solder pad area to manufacturers recommendation, the surface tension created in the molten solder during the re-flow process will bring badly aligned parts into the correct position.

8).

Question: I would like to have some parts to test. How do I go about getting prototypes?

Answer: Simply contact us. Bergquist can take care of all of your prototype needs. Obviously we can supply them ourselves, but we also have a network of local printed circuit shops familiar with processing Thermal Clad. They can supply prototypes on our behalf or you can work directly with them. All you need to get started is:

Circuit pattern layout (preferably in electronic format i.e. Gerber)
Mechanical design giving:
- positions for holes and their size
- overall dimensions
- dimensions linking the artwork traces to a mechanical feature
  (i.e. dimensions of fiducial to datum edges)
The material specification
The required finish

9).

Question: What are the basic panel sizes of Thermal Clad?

Answer: The basic panel sizes are 609 x 457mm (24 x 18 inches) or 482 x 406mm (19 x 16 inches). Each panel has a border of 12.7mm (0.5 inches) which should be kept clear of active electrical tracks / traces. The border around the outside of the panel is normally used for tooling holes during the circuit processing of the material.

10).

Question: Which is the lowest-cost method for extracting my part out of the panel?

Answer: There is no simple answer to this one as each customer design will be different. As a general rule, if your volumes are going to go above 5000 pieces, then you might want to consider a punch tool. If the part has an irregular shape, then punching or routing is normally used. If you design a rectangular part (i.e. no radii) then v-scoring offers good material utilization.

11).

Question: "What is ISO 9001:2000?"

Answer: The ISO certification is the adoption of a quality management system that is a strategic decision of the organization. This International Standard specifies requirements for a quality management system where an organization:
a) needs to demonstrate its ability to consistently provide product that meets customer and applicable regulatory requirements, and
b) aims to enhance customer satisfaction through the effective application if the system, including processes for continual improvement of the system and the assurance of conformity to customer and regulatory requirements.
Definition taken from Quality Associates International, Inc web page.