Technical Information - How to - Ordering Heat Sinks with Thermal Tape

Introduction

All of our standard series heat sinks can be ordered with pre-applied thermal tape per each customer's requirements. There are some general guidelines for choosing the correct thermal tape and size.

Selection of type of tape

For metal or ceramic packages, we offer Chomerics T412. This tape offers the highest thermal conductivity/lowest thermal impedance of any of the tapes we carry. It must not be used on plastic packages or the bond may eventually fail. Available in any size.

For plastic packages, we offer several varieties of thermal tape:

Bergquist BP105 .005" thickness	Offers very good performance for plastic packages. We only carry this material in 35mm squares.
Chomerics T411 .011" thickness	Available in any size. Offers good performance for plastic packages. Relatively thick material conforms to surfaces that are not perfectly flat.
3M 8815 .015 " thickness	Available in any size. Thick compliant material conforms to packages that may be concave or convex, improving the thermal performance and bond strength.

For detail of each tape specification, please check Online Catalog - Thermal tape.

Tape Size

Standard Tape Size

Tape Size (mm) Type	14	17	20	23	25	28	30	32	35	38	40	42	45	48	50	58	Standard Sheet Size
T412	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	(6"x12")
T411	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	( 6"x12" )
BP105									X

Tape Size
(mm)

Type

Standard
Sheet Size

T412

(6"x12")

T411

( 6"x12" )

BP105

Choose a piece of tape that is large enough to completely cover the contact area plus and additional 1.5mm in each direction. The extra material ensures that the tape will cover the package contact area if it the heat sink not perfectly centered. Additionally, if the package size is close to the size of the heat sink, leave about 1mm of space between the edge of the heat sink and the tape. For example, if the LPD40-15B is used on a 40mm package, the proper tape size should be 38mm square.

Note

If the chip/package's surface is slightly concave in shape, we recommend the use of tape that is slightly smaller than the size of the chip's contact area, approximately 85%. This ensures that the tape will only be in contact with the center(hot spot) of the chip/package. The worst case scenario would be a concave package, where only the outer perimeter of the package is in contact with the heat sink. Another option for a non-flat/concave package would be the choice of 3M 8815 tape. The 3M 8815 tape is thicker and will conform to a concave surface better than the thinner, less compliant, tapes.

Quickly creating and ordering a part number for a standard series heat sink with tape

We have devised a intuitive system to quickly come up with a part number that can be immediately ordered.

Step

Choose the heat sink series and size that is appropriate for your application from our on-line catalog. For example, the LPD40-15B may be the proper choice for a 35mm BGA package, depending on a customer's thermal requirements.
Choose the proper type of thermal tape.
Choose the correct tape size.
Create a part name by combining the heat sink part number along with the tape type and size.

Example 1 : LPD40-15B-T412-38

If an LPD40-15B were going to be used on a metal 35mm package, the correct tape choice would be a 38mm piece of T412. This specifies a standard LPD40-15B heat sink with a 38x38mm piece of Chomerics T412.

Once the heat sink/tape choice and part number are chosen, please contact us for a quote. Standard series heat sinks and tape are carried in stock. In most cases, samples and initial order quantities can be shipped within 1 day.