PCB technologies / PROJECT FIELD GUIDE

High-Tg PCBs

Review material performance across assembly and operating temperatures.

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ENGINEERING → PROCUREMENT → PRODUCTION

THE PRACTICAL ANSWER

What to know before you decide

A high-Tg PCB uses a laminate with an elevated glass-transition temperature, but Tg is only one part of thermal material selection. It does not directly state a safe continuous operating temperature or guarantee resistance to every soldering process. Review decomposition behavior, thermal expansion, moisture and the intended assembly and service exposure as applicable. Compare exact grades and test methods, then establish a construction and validation plan around the product's real thermal risks.

01 / DECISION GUIDE

Make the trade-offs explicit

Describe the exposure instead of a label

List assembly passes, possible rework and expected operating temperatures at relevant locations. Include duration and cycling where they matter. A request for high Tg without an exposure profile leaves the material reviewer guessing. Distinguish brief processing excursions from sustained service because the property needed to assess one may not answer the other.

Compare a set of relevant properties

Read Tg alongside other thermal and mechanical data, including the test methods and conditions. For a plated-hole design, dimensional change through the board can be relevant to interconnect stress. Avoid ranking materials by one headline value when the design depends on several properties. Keep the comparison focused on the identified failure mechanisms.

Include the complete construction

Layer count, dielectric arrangement, copper distribution and hole geometry influence how the board experiences thermal processing. Review these with the material proposal rather than selecting a grade in isolation. If a higher-Tg option changes thickness availability or processing, resolve the resulting design effects before release instead of assuming a drop-in change.

Validate the intended use

Select tests or build evidence that address the specific concern, such as assembly exposure or temperature cycling. Record the material and stack-up used in the validation build. A data-sheet comparison helps select candidates; it does not replace evidence for a demanding finished-board construction. Carry the approved construction into repeat procurement.

02 / SIDE BY SIDE

Compare the choices

high Tg PCB material selection — planning considerations
Property or condition	What it helps describe	What it does not establish alone
Tg	Transition in material behavior	Continuous operating rating
Thermal expansion	Dimensional change with temperature	Complete interconnect life
Decomposition behavior	Thermal degradation under a test	Every assembly process margin
Time at temperature	Exposure under defined conditions	All service environments
Actual board validation	Behavior of a chosen construction	Unreviewed material substitutes

03 / REVIEW BEFORE RELEASE

Questions that prevent rework

Tg used as maximum operating temperature

Continuous use requires a broader material and product assessment. Do not equate the two numbers.

Higher Tg assumed equivalent in every respect

Electrical, mechanical and processing properties can differ. Compare the exact grades.

Rework exposure omitted

Include realistic repair and second-side processes in the thermal history review.

04 / COMMON QUESTIONS

Get a clear answer

Is a higher Tg always better?

Not by itself. Select the material against the properties and exposure that affect the design, then consider availability and processing. A higher number on one property does not prove overall equivalence.

Does high Tg prevent delamination?

It does not provide a universal guarantee. Moisture, construction, processing and other material properties contribute to thermal reliability.

What should a high-Tg material request contain?

Provide exact grade if selected, stack-up, assembly exposure and relevant service conditions. State which property requirements must be maintained if alternatives are proposed.

Technical references

Check each source’s scope and revision against your project requirements. Confirm the proposed construction with your manufacturing partner.

YOUR PROJECT / YOUR NEXT STEP

Build a useful project brief

Create a thermal-material review brief without treating Tg as a service-temperature rating.

Use this planning aid to prepare a review. It does not approve a design or estimate a price. Selections are processed locally and are not submitted by this tool.

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01 / Capabilities