TWI465166B - Method and apparatus for reducing stress of printed circuit board - Google Patents

Description

Circuit board stress reduction method and circuit board stress relief device

The present invention relates to the field of circuit board technology, and in particular, to a method for stress reduction of a circuit board and a stress relief device for the circuit board.

At present, with the market demand for consumer electronic products (including mobile phones, notebook computers, digital cameras, game consoles, etc.), the printed circuit boards (PCBs) of electronic products are also thin, light and high. Frequency and multi-functional development. The substrate is the basic material for manufacturing a printed circuit board. Generally, the substrate is a copper-clad laminate, which is impregnated with a resin adhesive by a reinforcing material, and is dried, cut, and cured. The billet is further laminated, and then the copper foil is coated, and the steel sheet is used as a mold and processed by a high temperature and high pressure forming process in a hot press.

However, in the process of drying, curing, etc., the substrate tends to accumulate stress inside. If the above stress is not released well, it is likely to cause the substrate to bend in a stress environment, and may also cause the substrate to rupture.

One of the objects of the present invention is to provide a method of stress reduction of a circuit board and a stress relief apparatus.

In order to achieve the above advantages, the method for removing stress of a circuit board provided by the present invention comprises the steps of: providing a substrate; providing a stress relief device, the stress relief device is provided with at least three temperature zones along its length; and heating the stress relief device, The temperature of each temperature zone is set at 129.5 ° C ~ 351 ° C, and the temperature of the temperature zone located in the middle area of the stress relief device is higher than the temperature of the temperature zone near the outlet and the inlet of the stress relief device; and the substrate is 0.2~ The speed of 3.0 m / min passes through the stress relief equipment.

In order to achieve the above advantages, the stress relief device of the circuit board provided by the present invention comprises a conveyor belt and a heating device. The stress relief device is provided with at least three temperature zones along its length, and the heating device is used to heat the temperature of each temperature zone to 129.5 ° C ~ 351 ° C, and the temperature in the temperature zone in the middle of the stress relief equipment is heated to a temperature higher than the temperature zone near the outlet and inlet of the stress relief device, the conveyor is used to 0.2 to 3.0 m / min of the circuit board The speed of the transmission of the past stress equipment.

In the present invention, by heating the stress relief device, the temperature of each temperature zone is located at 129.5 ° C to 351 ° C, and the temperature in the temperature zone located in the middle portion of the stress relief device is higher than that near the exit and the inlet of the stress relief device. The temperature of the temperature zone is passed through the stress-relieving device at a speed of 0.2 to 3.0 m/min to eliminate the thermal stress of the substrate, and to ensure that the deformation size (ie, the size of the expansion and contraction) of the substrate is kept within a predetermined expansion range. Therefore, the invention can simply and effectively release the stress of the substrate, avoid bending and cracking of the substrate in a stress environment, and ensure that the size of the substrate is maintained within the control range.

S101, S102, S103, S105, S107‧‧‧ steps

201‧‧‧ heating device

203‧‧‧Conveyor belt

FIG. 1 is a flow chart showing the steps of a method for removing stress of a circuit board according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the main structure of a stress reduction device for a circuit board according to an embodiment of the present invention.

The specific embodiments, structures, features and functions of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

FIG. 1 is a flow chart showing the steps of a method for removing stress of a circuit board according to an embodiment of the present invention. Please refer to Figure 1. The method for removing stress of the circuit board of the embodiment of the present invention may include the following steps:

Step S101: providing a substrate.

In this step, the substrate may be an existing copper-clad laminate or the like. The method of manufacturing the substrate is the same as the conventional basic manufacturing method, and will not be described herein.

Step S102: A resistor is disposed on the substrate, and carbon ink is coated on the resistor.

Step S103: providing a stress relief device, the stress relief device is provided with at least three temperature zones along its length.

Step S105: heating the stress relief device so that the temperature of each temperature zone is between 129.5 ° C and 351 ° C, and the temperature of the temperature zone located in the middle region of the stress relief device is higher than that of the temperature zone adjacent to the outlet and the inlet of the stress relief device. temperature.

In this step, the temperature in the temperature zone in the middle region of the stress relief device is 189 ° C ~ 351 ° C, and the temperature in the temperature zone near the entrance of the stress relief device is 178.5 ° C ~ 331.5 ° C, near the exit of the stress relief device The temperature in the temperature zone is 129.5 ° C ~ 240.5 ° C. Preferably, the temperature of the temperature zone located in the intermediate portion of the stress relief device is 270 ° C, near the temperature of the temperature zone at the inlet of the stress relief device At 255 ° C, the temperature in the temperature zone near the outlet of the stress relief device is 185 ° C.

Specifically, the stress relief device is provided with 3 to 25 temperature zones. In one embodiment of the present invention, the stress relief device is provided with 12 temperature zones, and the temperature ranges of the 12 temperature zones are: 178.5 ° C ~ 331.5 ° C, 175 ° C ~ 325 ° C, respectively, from the inlet and the outlet of the stress relief device. 175°C~325°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 189°C~351°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 161°C ~299 ° C, 129.5 ° C ~ 240.5 ° C. Preferably, the temperature of the 12 temperature zones can be sequentially from the inlet and the outlet of the stress relief device: 255 ° C, 250 ° C, 250 ° C, 250 ° C, 250 ° C, 250 ° C, 250 ° C, 270 ° C, 250 ° C, 250 °C, 230 ° C, 185 ° C.

In this step, heating the stress relief device includes heating each temperature zone to a predetermined temperature by varying the power of the infrared source provided to the strain relief device.

Step S107: Pass the substrate through the stress relief device at a speed of 0.2 to 3.0 m/min.

In this step, the substrate is passed through a stress relief device at a speed of 0.2 to 3.0 m/min. Preferably, the substrate can be passed through a stress relief device at a rate of 0.84 m/min. In this way, the substrate is sequentially heated by at least three temperature zones of the stress relief device, and the process of first heating and lowering the temperature of the substrate can effectively eliminate the stress generated in the baking, curing, and the like of the substrate, and can ensure the substrate. The deformation size remains within the predetermined expansion and contraction range.

The following is an experimental verification of the extent of the substrate obtained by the stress-relief method of the circuit board of the present invention. The experimental data is as follows: the substrate is passed through a de-stressing device with 12 temperature zones at a speed of 0.84 m/min. The set temperature is as shown in Table 1. According to the test conditions in Table 1, through three experiments, each time sampling 6 substrates for verification, it can be measured using the circuit board of the present invention. The deformation of the substrate obtained by the stress method and the components (including resistance, carbon ink, etc.) disposed thereon are maintained within a predetermined expansion range (+/- 2 mil).

In an embodiment of the present invention, the temperature of each temperature zone is set to be between 129.5 ° C and 351 ° C by heating the stress relief device, and the temperature in the temperature zone located in the middle portion of the stress relief device is higher than that near the outlet of the stress relief device and The temperature of the temperature zone at the inlet passes the substrate through the stress relief device at a speed of 0.2 to 3.0 m/min to eliminate the thermal stress of the substrate and ensure that the deformation size of the substrate (ie, the size of the expansion and contraction) remains within the predetermined expansion and contraction range. . The heating zone is also heated to a predetermined temperature by changing the power of the infrared light source supplied to the stress relief device, so that the invention can simply and effectively release the stress of the substrate, thereby avoiding bending and cracking of the substrate in a stress environment. And can also ensure that the size of the substrate is maintained within the control range.

2 is a main architectural diagram of a stress relief device for a circuit board according to an embodiment of the present invention. Referring to FIG. 2, the stress relief device of the circuit board includes: a heating device 201 and a conveyor belt 203.

The stress relief device described above is provided with at least three temperature zones along its length. Specifically, the stress relief device is provided with 3 to 25 temperature zones, preferably, The force device is provided with 12 temperature zones, and the number of the temperature zones in the present invention can be adjusted according to relevant conditions such as the length of the stress relief device.

The heating device 201 is for heating the temperature of each temperature zone to 129.5 ° C to 351 ° C, and heating the temperature of the temperature zone located in the intermediate portion of the stress relief device to a temperature higher than the temperature zone near the outlet and the inlet of the strain relief device.

Further, the heating device 201 can also heat each temperature zone to a predetermined temperature by changing the power of the infrared light source supplied to the strain relief device. In the embodiment where the stress relief device is provided with 12 temperature zones, the temperature range of the 12 temperature zones is from 178.5 ° C to 331.5 ° C, 175 ° C to 325 ° C, and 175 ° C from the inlet and the outlet of the stress relief device. 325°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 189°C~351°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 161°C~299°C 129.5 ° C ~ 240.5 ° C. That is to say, the temperature of the temperature zone located in the intermediate portion of the stress relief device is preferably 189 ° C ~ 351 ° C, and the temperature of the temperature zone near the inlet of the stress relief device is preferably 178.5 ° C ~ 331.5 ° C, close to the outlet of the stress relief device The temperature in the temperature zone is preferably 129.5 ° C ~ 240.5 ° C. In one embodiment of the invention, the temperature of the 12 temperature zones is preferably 255 ° C, 250 ° C, 250 ° C, 250 ° C, 250 ° C, 250 ° C, 250 ° C, 270 at the inlet and outlet of the stress relief device. °C, 250 ° C, 250 ° C, 230 ° C, 185 ° C. That is, in this embodiment, the temperature of the temperature zone located in the intermediate portion of the strain relief device is 270 ° C, and the temperature of the temperature zone near the inlet of the stress relief device is 255 ° C, near the exit of the strain relief device. The temperature in the temperature zone is 185 °C.

Conveyor belt 203 is used to transport the board to the stress device at a speed of 0.2 to 3.0 meters per minute. Preferably, the substrate can be passed through a stress relief device at a rate of 0.84 meters per minute. In this way, the substrate is sequentially heated by at least three temperature zones of the stress relief device, and the process of first heating and then cooling down can effectively eliminate In addition to the stress of the substrate, it is possible to ensure that the deformation of the substrate is maintained within a predetermined range of expansion and contraction.

In an embodiment of the present invention, the temperature of each temperature zone is set to be between 129.5 ° C and 351 ° C by heating the stress relief device, and the temperature in the temperature zone located in the middle portion of the stress relief device is higher than that near the outlet of the stress relief device and The temperature of the temperature zone at the inlet passes the substrate through the stress relief device at a speed of 0.2 to 3.0 m/min to eliminate the thermal stress of the substrate and ensure that the deformation size of the substrate (ie, the size of the expansion and contraction) remains within the predetermined expansion and contraction range. . The heating zone is also heated to a predetermined temperature by changing the power of the infrared light source supplied to the stress relief device, so that the invention can simply and effectively release the stress of the substrate, thereby avoiding bending and cracking of the substrate in a stress environment. And can also ensure that the size of the substrate is maintained within the control range.

In the present invention, the temperature zone located in the middle portion of the stress relief device refers to the portion of the temperature zone in which the temperature is higher than the temperature zone of the middle portion of the stress relief device, and the temperature of the temperature zone of the intermediate zone is opposite to the sides thereof. The temperature of the temperature zone has a range of temperature rises. In a specific embodiment, the temperature zone of the intermediate zone may comprise a temperature zone or a plurality of temperature zone, and the temperature zone near the inlet or outlet of the stress relief device is located a portion of the stress relief device adjacent to the inlet or outlet and having a lower temperature than the portion of the intermediate region. In particular embodiments, the temperature region adjacent the inlet or outlet of the strain relief device may also include a temperature zone. Or multiple temperature zones.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention. A skilled person may make some modifications or modifications to equivalent variations using the technical contents disclosed above without departing from the scope of the present invention. Any simple modifications, equivalent changes and modifications to the above embodiments in accordance with the technical spirit of the present invention are still within the scope of the technical solutions of the present invention.

S101, S102, S103, S105, S107‧‧‧ steps

Claims (10)

A method for destressing a circuit board, comprising the steps of: providing a substrate; providing a stress relief device, the stress relief device is provided with at least three temperature zones along its length; heating the stress relief device to temperature of each temperature zone Located at 129.5 ° C to 351 ° C, and the temperature in the temperature zone located in the middle portion of the stress relief device is higher than the temperature in the temperature zone near the outlet and the inlet of the stress relief device; and the substrate is 0.2 to 3.0 m / min The speed is passed through the stress relief device. The method for stress-removing a circuit board according to claim 1, wherein the temperature in the temperature region of the intermediate portion of the stress relief device is 189 ° C to 351 ° C, near the temperature zone at the entrance of the stress relief device. The temperature is 178.5 ° C ~ 331.5 ° C, and the temperature in the temperature zone near the outlet of the stress relief device is 129.5 ° C ~ 240.5 ° C. The method of stress reduction of a circuit board according to claim 2, wherein a temperature in a temperature zone in an intermediate portion of the stress relief device is 270 ° C, and a temperature in a temperature zone near an inlet of the stress relief device is 255. °C, the temperature in the temperature zone near the exit of the stress relief device is 185 °C. The method for removing stress of a circuit board according to claim 1, wherein the stress relief device has 3 to 25 temperature zones. A method for removing stress of a circuit board as described in claim 4, The destressing device has 12 temperature zones, and the temperature ranges of the 12 temperature zones are: 178.5 ° C ~ 331.5 ° C, 175 ° C ~ 325 ° C, 175 ° C ~ 325 ° C, respectively, from the inlet and outlet of the stress relief device, 175°C~325°C, 175°C~325°C, 175°C~325°C, 189°C~351°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 161°C~299°C, 129.5°C ~240.5 °C. The method of stress removing a circuit board according to claim 1, wherein the step of heating the stress relief device comprises: heating each temperature zone to a predetermined temperature by changing a power of an infrared light source supplied to the strain relief device. A stress reduction device for a circuit board, comprising: a conveyor belt and a heating device, wherein the stress relief device is provided with at least three temperature zones along a length thereof, the heating device is configured to heat the temperature of each temperature zone to 129.5 °C~351 °C, and the temperature of the temperature zone in the middle zone of the stress relief device is heated to a temperature higher than the temperature zone near the outlet and the inlet of the stress relief device, the conveyor belt is used to 0.2 to 3.0 meters of the circuit board The speed of the minute is transmitted through the stress relief device. The stress relief device of the circuit board of claim 7, wherein the stress relief device has 3 to 25 temperature zones. The destressing device of the circuit board of claim 8, wherein the stress relief device has 12 temperature zones, and the temperature ranges of the 12 temperature zones are from the inlet and the outlet of the stress relief device: 178.5 °C~331.5°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 175°C~325°C, 189°C~351°C, 175°C~325°C, 175°C~ 325 ° C, 175 ° C ~ 325 °C, 161 ° C ~ 299 ° C, 129.5 ° C ~ 240.5 ° C. The stress relief device of the circuit board of claim 7, wherein the temperature in the temperature zone in the intermediate portion of the stress relief device is 270 ° C, and the temperature in the temperature zone near the inlet of the stress relief device is 255. °C, the temperature in the temperature zone near the exit of the stress relief device is 185 °C.