Pcb Cte Z. The materials have low Dk, low loss and high speed signal capa
The materials have low Dk, low loss and high speed signal capability but do not The Coefficient of Thermal Expansion, or CTE, is the rate of expansion of a PCB material as it heats up. Z-axis CTE (coefficient of thermal expansion) is the expansion rate through the PCB thickness. Conclusions Development of new PCB materials containing multiple thermal control layers has demonstrated higher thermal conductivity, high PCB板材的热膨胀系数（CTE） , 材料的热膨胀系数是材料物理特性之一，温度的变化造成的变形以及带来的应力作用是无法改变的。 The CTE is often not the same in all axes (that is, not ‘isotropic’). CTE is expressed in parts per million (ppm) expanded for every degree Celsius that it is heated. To measure Z-axis CTE, the most common method is Thermal Mechanical Analysis (TMA). This test provides two key values: α1-CTE – The It is not acceptable for a material under thermal stress to expand in X or Y directions, but it must expand in the Z direction. , FR4 CTE (Coefficient of Thermal Expansion) is the degree to which FR-4 material expands in response to changes in temperature. Thermal expansion perpendicular to the PCB surface, critical for via reliability. In PCB laminates, for example, the values are different in the plane of the board (X-Y) and through its thickness (Z). g. 1 times that of copper (17 ppm/°C). The Printed Circuit Board (PCB), the ground base of all electronics, is reaching limitations due to the material 2、为什么PCB板材需要关注Z轴热膨胀系数？ Z轴CTE对PCB尤其是多层PCB的镀覆孔的可靠性有很重要的影响。 PCB板在热处理、高温焊接和运行操作时，受热会引起Z轴膨胀，进而会受 Our PCB Material Reference & Selection Guide covers the key characteristics of popular circuit materials including dielectric constant (Dk), dissipation factor (Df), However, in the Z axis, which is perpendicular to the surface of the PCB, the material can freely expand or contract. has analyzed the typical failures in PTH induced by thermal and mechanical reasons. 3 Most thermal analysis equipment have the software capability to determine Tg and CTE values; it is recommended that this approach be used for consistency, provided test parameters (e. One of the FR-4 是最常見的PCB材料，但它的 Z軸CTE在Tg附近急劇增加，這可能會對通孔造成壓力。 聚醯亞胺 具有比 FR-4 更好的高溫穩定性和更低的 CTE，使其成為惡 Today’s materials & their limitations Table 1 displays the properties of the dielectric materials that are used to make PCBs. The CTE is rarely FR-4 FR-4 glass epoxy is a popular and versatile high-pressure thermoset plastic laminate with good strength to weight ratio. 093”) a layer of CCL can be placed one layer un er each surface layer. . Non-woven ara-mid A higher Tg value favors a low CTE-z value which represents the absolute expansion in the z-axis. For medium thickness PCBs (<0. This would allow for an ideal optimization of thermal, CTE and rigidity In the world of electronics manufacturing, understanding the physical properties of materials is crucial for designing reliable and long-lasting products. The expansion of PCB materials occurs volumetrically CTE：Coefficient of thermal expansion热胀系数，通常衡量 PCB板材性能的是线性膨胀系数，定义为：单位温度改变下长度的增加量与的原长度的比值，如Z X-y-CTE (coefficient of thermal expansion): The purpose of knowing a material’s x-y-CTE, measured from -40° to 125°C in ppm/°C, is to assess the Factors that influence material selection Reliability: Thermal Mechanical: Lead free assembly X,Y,Z CTE Long term life Conduction cooling PCB Trace Technologies Inc. The PCB CTE is a core parameter for measuring the dimensional stability of PCB boards under temperature changes, which directly affects the We’ve compiled important PCB CTE values for your reference, and we’ll describe the importance of avoiding CTE mismatches in material selection. This means that in a classic PCB PCB. If the z-axis CTE is closely matched to copper, expansion of the PCB Introduction The evolution of electronics is now reaching the threshold of design capability. Selecting the right PCB laminates and materials for your design is very important as it can impact the overall performance of the board. Critical in Z-axis – typically above Tg and the expansion is greater. As a Conclusion Choosing the right PCB material involves carefully balancing the CTE (z) and Tg with the specific requirements of your application. In the Z direction, the Whenever the temperature gets near to a Tg, the z-axis CTE dramatically increases from 4 to 14 times the value of the x-y axis. Apart from mechanical reasons The z-axis CTE is a concern because as the PCB expands during heating, it can elongate plated via holes and cause fracturing. Unlike X-Y axes (constrained According to the IPC - 4101 standard, the CTE of the Z - axis of an FR4 substrate is 70 ppm/°C (from room temperature to the Tg value), which is 4. For high-reliability designs, especially those Heavy copper, for example, has the ability to manage the ther-mal issues on a PCB, but has limi-tations in terms of CTE control, high density (weight) as well as manufacturability. Therefore, it is crucial to The combustion products produced by pyrolysis of the epoxy resin in a PCB laminate, were transferred from the thermogravimetric balance output to a heated gas cell located inside a Fourier The main ones that we would consider first include: CTE A measure of how much the material expands when heated. If CTE insufficient PCBs with a low CTE (coefficient of thermal expansion) are especially important in high-precision electronics, high-frequency circuits, or The Z-axis CTE mismatch between copper plating (approximately 16-18 ppm/°C) and the PCB substrate (55-60 ppm/°C for FR-4) creates one of 6. With near zero water absorption, FR-4 is most commonly used as an Signal integrity isn’t the full story, the thermal properties of your PCB substrate materials are also important for reliability.