Performance requirements, standards, and related testing methods for metal based copper clad laminates

Performance requirements, standards, and related testing methods for metal based copper clad laminates

1、 Performance requirements and standards

Some industrial developed countries, such as Japan, were able to produce aluminum based copper clad panels and achieve industrial production in the early 1970s, but the Japanese Industrial Standards (JIS) did not establish standards for aluminum based copper clad panels. So far, influential international standardization organizations such as IPC, IEC, NEMA, and ASTM have not yet developed standards for aluminum based copper clad panels. In China, with the gradual expansion of the aluminum based copper clad plate market, the PCB and copper clad plate industry urgently requires the formulation of industry standards for aluminum based copper clad plates. In 1999, Factory 704 was responsible for drafting and formulating the military standard for the electronic industry, "Specification for Flame retardant aluminum based copper clad foil laminated plates.". The main technical requirements are introduced as follows.

1. Dimensional requirements

(1) The nominal surface dimensions and allowable deviations of aluminum based copper clad panels shall comply with the provisions of Table 5-3. Non nominal surface dimensions and their deviations shall be agreed upon by both the supply and demand parties.

(2) The nominal thickness and deviation of aluminum based foil sheet should comply with the provisions in Table 5-4.

(3) When inspecting the verticality of aluminum based foil sheets according to GB/T 4722, it should comply with the provisions of Table 5-5.

(4) The warpage of aluminum based foil sheets should comply with the provisions of Table 5-6 when tested according to GB 4677.5.

When measuring the degree of warping, the sample size should not exceed 300mm x 300mm. If it is a whole board or the side length is greater than 300mm, it should be cut into 300mm x 300mm. But when calculating, the side length is the measured side length.

2. Appearance

The end face of the aluminum based foil plate should be neat and free of layering, cracks, and burrs.

The surface of the aluminum plate is flat, the oxide film is uniform, smooth, and there should be no defects such as dents, cracks, scratches that affect its use.

The copper foil surface should not have any bubbles, wrinkles, pinholes, scratches, pitting, or adhesive spots that affect its use. Any discoloration or dirt should be able to be wiped off with a hydrochloric acid solution with a density of 1.02g/c ㎡ or a suitable organic solvent.

3. Performance requirements

The various properties of aluminum based foil sheets should comply with the provisions of Table 5-7

The performance indicators of the dielectric constant and dielectric loss tangent of a pair of LI-11 aluminum based copper-clad laminates at high frequencies shall be negotiated between the supply and demand parties.

2、 Inspection methods for aluminum based copper clad panels

The military standard for the electronics industry, "Specification for Flame-retardant Aluminum based Copper Clad Laminate," has developed two specific testing methods for aluminum based copper clad laminates:

1. Measurement method for dielectric constant and dielectric loss tangent - Variable Q-value series resonance method;

2. Thermal resistance measurement method.

1. Measurement method for dielectric constant and dielectric loss tangent - Variable Q-value series resonance method

1) Method principle: This method utilizes the principle of connecting the sample and tuning capacitor in series to a high-frequency circuit, measuring the quality factor E value of the series circuit, and measuring the dielectric constant and dielectric loss factor of large capacitance, small resistance, and small inductance plate shaped samples. The measurement circuit is shown in Figure 5-3.

3) Equipment, instruments, and materials

1 Eddy current thickness gauge (TC-103 or equivalent) with a range of 0-200 μ m) Accuracy to+-1/1m.

The Q value measurement range of the 2 Q meter is 10~600, and the capacitance measurement range is 0~400pF, with an accuracy of+-0.2pF.

The electrode device should be clean and its own dielectric loss should be minimized as much as possible. Adopting a two electrode system, the electrode size and other requirements shall comply with the provisions of GB1409.

4 0.02mm annealed aluminum foil.

5 Medical Vaseline or Silicone.

6 high-frequency oscillation power supply, with a frequency of 0.1~100MHz.

3) Sample

Cut and process 4 square specimens with dimensions of 55mm x 55mm.

Etch and remove the copper foil according to method 3031 in GJB 1651.

4) Program

1. Use a small amount of low dielectric loss materials such as medical Vaseline or silicone grease to stick the aluminum foil onto the sample, and no pores or wrinkles should be visible on the attached aluminum foil

2. Pre treat the sample according to the product standard and stick 50 on it φ Mm electrodes, with the upper and lower electrodes aligned concentric.

Connect the series clamp and measuring microelectrode according to the circuit diagram.

4. Adjust the frequency accurately and select an appropriate auxiliary inductor to connect to the circuit.

5. Place the tested sample into the measuring microelectrode and tighten it.

Tighten the short-circuit ring on the series fixture to short-circuit the tested sample, adjust the tuning capacitor to make the test circuit resonant, and record C1 and Q1.

Release the short-circuit ring and connect the tested sample to the test circuit. Adjust the tuning capacitor again to make the test circuit resonant, and record Q2 and C2.

Measure the insulation layer thickness of each sample and record the average thickness of three points on each sample.

5) The formula for calculating the tangent of the dielectric loss angle and the dielectric constant is as follows:

6) Result

Take the average dielectric constant of 4 samples as the test result;

Take the average tangent value of the dielectric loss angle of four samples as the test result

7) Report

The individual and average values measured on 13 samples;

2. Pre treatment conditions for the sample;

3. Environmental conditions during measurement;

Any abnormal phenomena or differences from the prescribed procedures during the measurement.

2. Thermal resistance testing method

The principle of ($) method is that temperature difference is the driving force for heat transfer. Under stable working conditions, the thermal conductivity P=T1-T2/R, where P is the thermal conductivity (W), T1, T2 are the surface temperatures on both sides of the object (℃), and R is the thermal resistance (℃/W).

The schematic diagram of thermal resistance measurement is shown in Figure 5-4.

2) Instrument and equipment materials

1 high-power transistor with a power of 5W, packaged in TO-220 format.

One high-power transistor power supply (consisting of a DC regulator and related circuits) is used to keep the transistor in a DC steady state.

3 radiators, made of copper plate and placed in a constant temperature water bath.

Two temperature sensors are required to be placed at the two temperature measurement points shown in Figure 5-4, and the impact on the temperature of these two points can be ignored.

3) Two samples with dimensions of 30mmx40mm x plate thickness.

4) Program

The sample shall be treated for no less than 16 hours under conditions of temperature ranging from 15 to 35 ℃, relative humidity ranging from 45% to 75%, and air pressure ranging from 86 to 106 kPa.

As shown in Figures 5-4, place the sensor of the thermometer at measurement points 1 and 2, apply thermal conductive silicone grease to the contact part between the sample and the transistor, as well as the contact part between the heat sink and the sample, and fix the three together, so that there is no gap between the transistor and the sample, and between the sample and the heat sink.

Connect the transistor to the power supply.

Turn on the power supply switch and record the temperature of temperature measurement points 1 and 2 every 5 minutes. When the temperature stabilizes (about 30 minutes), read T1 and T2 from the temperature display. And measure the voltage VcE and collector current Ic between the collector and emitter of the transistor.

3、 UL certification for aluminum based copper clad panels

Obtaining UL certification is the passport for products to enter the international market. The safety standard UL746E for industrial laminates used in printed circuits stipulates that rigid industrial laminates with UL/ANSI model identification should pass 16 test items, as shown in Table 5-8.

Performance requirements, standards, and related testing methods for metal based copper clad laminates

1、 Performance requirements and standards

Some industrial developed countries, such as Japan, were able to produce aluminum based copper clad panels and achieve industrial production in the early 1970s, but the Japanese Industrial Standards (JIS) did not establish standards for aluminum based copper clad panels. So far, influential international standardization organizations such as IPC, IEC, NEMA, and ASTM have not yet developed standards for aluminum based copper clad panels. In China, with the gradual expansion of the aluminum based copper clad plate market, the PCB and copper clad plate industry urgently requires the formulation of industry standards for aluminum based copper clad plates. In 1999, Factory 704 was responsible for drafting and formulating the military standard for the electronic industry, "Specification for Flame retardant aluminum based copper clad foil laminated plates.". The main technical requirements are introduced as follows.

1. Dimensional requirements

(1) The nominal surface dimensions and allowable deviations of aluminum based copper clad panels shall comply with the provisions of Table 5-3. Non nominal surface dimensions and their deviations shall be agreed upon by both the supply and demand parties.

(2) The nominal thickness and deviation of aluminum based foil sheet should comply with the provisions in Table 5-4.

(3) When inspecting the verticality of aluminum based foil sheets according to GB/T 4722, it should comply with the provisions of Table 5-5.

(4) The warpage of aluminum based foil sheets should comply with the provisions of Table 5-6 when tested according to GB 4677.5.

When measuring the degree of warping, the sample size should not exceed 300mm x 300mm. If it is a whole board or the side length is greater than 300mm, it should be cut into 300mm x 300mm. But when calculating, the side length is the measured side length.

2. Appearance

The end face of the aluminum based foil plate should be neat and free of layering, cracks, and burrs.

The surface of the aluminum plate is flat, the oxide film is uniform, smooth, and there should be no defects such as dents, cracks, scratches that affect its use.

The copper foil surface should not have any bubbles, wrinkles, pinholes, scratches, pitting, or adhesive spots that affect its use. Any discoloration or dirt should be able to be wiped off with a hydrochloric acid solution with a density of 1.02g/c ㎡ or a suitable organic solvent.

3. Performance requirements

The various properties of aluminum based foil sheets should comply with the provisions of Table 5-7

The performance indicators of the dielectric constant and dielectric loss tangent of a pair of LI-11 aluminum based copper-clad laminates at high frequencies shall be negotiated between the supply and demand parties.

2、 Inspection methods for aluminum based copper clad panels

The military standard for the electronics industry, "Specification for Flame-retardant Aluminum based Copper Clad Laminate," has developed two specific testing methods for aluminum based copper clad laminates:

1. Measurement method for dielectric constant and dielectric loss tangent - Variable Q-value series resonance method;

2. Thermal resistance measurement method.

1. Measurement method for dielectric constant and dielectric loss tangent - Variable Q-value series resonance method

1) Method principle: This method utilizes the principle of connecting the sample and tuning capacitor in series to a high-frequency circuit, measuring the quality factor E value of the series circuit, and measuring the dielectric constant and dielectric loss factor of large capacitance, small resistance, and small inductance plate shaped samples. The measurement circuit is shown in Figure 5-3.

3) Equipment, instruments, and materials

1 Eddy current thickness gauge (TC-103 or equivalent) with a range of 0-200 μ m) Accuracy to+-1/1m.

The Q value measurement range of the 2 Q meter is 10~600, and the capacitance measurement range is 0~400pF, with an accuracy of+-0.2pF.

The electrode device should be clean and its own dielectric loss should be minimized as much as possible. Adopting a two electrode system, the electrode size and other requirements shall comply with the provisions of GB1409.

4 0.02mm annealed aluminum foil.

5 Medical Vaseline or Silicone.

6 high-frequency oscillation power supply, with a frequency of 0.1~100MHz.

3) Sample

Cut and process 4 square specimens with dimensions of 55mm x 55mm.

Etch and remove the copper foil according to method 3031 in GJB 1651.

4) Program

1. Use a small amount of low dielectric loss materials such as medical Vaseline or silicone grease to stick the aluminum foil onto the sample, and no pores or wrinkles should be visible on the attached aluminum foil

2. Pre treat the sample according to the product standard and stick 50 on it φ Mm electrodes, with the upper and lower electrodes aligned concentric.

Connect the series clamp and measuring microelectrode according to the circuit diagram.

4. Adjust the frequency accurately and select an appropriate auxiliary inductor to connect to the circuit.

5. Place the tested sample into the measuring microelectrode and tighten it.

Tighten the short-circuit ring on the series fixture to short-circuit the tested sample, adjust the tuning capacitor to make the test circuit resonant, and record C1 and Q1.

Release the short-circuit ring and connect the tested sample to the test circuit. Adjust the tuning capacitor again to make the test circuit resonant, and record Q2 and C2.

Measure the insulation layer thickness of each sample and record the average thickness of three points on each sample.

5) The formula for calculating the tangent of the dielectric loss angle and the dielectric constant is as follows:

6) Result

Take the average dielectric constant of 4 samples as the test result;

Take the average tangent value of the dielectric loss angle of four samples as the test result

7) Report

The individual and average values measured on 13 samples;

2. Pre treatment conditions for the sample;

3. Environmental conditions during measurement;

Any abnormal phenomena or differences from the prescribed procedures during the measurement.

2. Thermal resistance testing method

The principle of ($) method is that temperature difference is the driving force for heat transfer. Under stable working conditions, the thermal conductivity P=T1-T2/R, where P is the thermal conductivity (W), T1, T2 are the surface temperatures on both sides of the object (℃), and R is the thermal resistance (℃/W).

The schematic diagram of thermal resistance measurement is shown in Figure 5-4.

2) Instrument and equipment materials

1 high-power transistor with a power of 5W, packaged in TO-220 format.

One high-power transistor power supply (consisting of a DC regulator and related circuits) is used to keep the transistor in a DC steady state.

3 radiators, made of copper plate and placed in a constant temperature water bath.

Two temperature sensors are required to be placed at the two temperature measurement points shown in Figure 5-4, and the impact on the temperature of these two points can be ignored.

3) Two samples with dimensions of 30mmx40mm x plate thickness.

4) Program

The sample shall be treated for no less than 16 hours under conditions of temperature ranging from 15 to 35 ℃, relative humidity ranging from 45% to 75%, and air pressure ranging from 86 to 106 kPa.

As shown in Figures 5-4, place the sensor of the thermometer at measurement points 1 and 2, apply thermal conductive silicone grease to the contact part between the sample and the transistor, as well as the contact part between the heat sink and the sample, and fix the three together, so that there is no gap between the transistor and the sample, and between the sample and the heat sink.

Connect the transistor to the power supply.

Turn on the power supply switch and record the temperature of temperature measurement points 1 and 2 every 5 minutes. When the temperature stabilizes (about 30 minutes), read T1 and T2 from the temperature display. And measure the voltage VcE and collector current Ic between the collector and emitter of the transistor.

3、 UL certification for aluminum based copper clad panels

Obtaining UL certification is the passport for products to enter the international market. The safety standard UL746E for industrial laminates used in printed circuits stipulates that rigid industrial laminates with UL/ANSI model identification should pass 16 test items, as shown in Table 5-8.