Method for reducing porcelain cracks of DCB substrate

Abstract

The invention discloses a method for reducing porcelain cracks of a DCB substrate, which is characterized in that a low-friction-coefficient polyether-ether-ketone resin insertion frame is used for three-stage ultrasonic washing of a single-sided copper-clad substrate, so that friction and abrasion between the insertion frame and the single-sided copper-clad substrate are reduced, and cracks are prevented from expanding due to thermal stress after sintering; and meanwhile, the temperature of the constant-temperature area during sintering is reduced to perform second surface sintering, so that ceramic cracks generated in the sintering process of the single-sided copper-clad substrate and the copper foil are reduced, further expansion of the cracks is prevented, and the product yield is improved.

Description

Technical Field

[0001] This application relates to the technical field of copper - clad ceramic substrate preparation, and specifically relates to a method for reducing porcelain cracking of DCB substrates. Background Art

[0002] DCB technology uses copper - containing eutectic liquid of copper to directly bond copper to ceramics. Its basic principle is to introduce an appropriate amount of oxygen element between copper and ceramics before or during the bonding process. Within a certain temperature range, copper and oxygen form a Cu - O eutectic liquid, which infiltrates the copper foil to achieve the bonding of the ceramic substrate and the copper plate.

[0003] Currently, the production of copper - clad ceramic substrates is basically sintered in two steps, that is, sintering one side first and then the other side. However, there are the following problems: There is a lot of ash in the DCB sintering furnace. Therefore, before the second sintering of the DCB, the semi - finished products are usually cleaned. Stainless steel fixtures are usually used for inserting the plates for cleaning. During the cleaning process, it is found that there is a risk of collision when employees pick up the semi - finished products, and when the number of picked - up products is too large, the risk of collision will be greater, resulting in breakage. After sintering, due to thermal stress, porcelain cracks will expand. At the same time, when the sintering temperature is too high, the product cracks will expand deeper and longer, resulting in a reduction in the product yield and an increase in production costs.

[0004] In view of this, a method for reducing porcelain cracking of DCB substrates is provided. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for reducing porcelain cracking of DCB substrates. By using a rack made of a specific material for cleaning the single - sided copper - clad substrate, and at the same time, a constant - temperature zone within a specific temperature range is used for the second - side sintering, the risk of porcelain cracking generated during the DCB substrate sintering process is reduced, and the problems existing in the prior art are solved.

[0006] To solve the above - mentioned technical problems, the present invention adopts the following solutions:

[0007] A method for reducing porcelain cracking of DCB substrates includes the following steps:

[0008] Step 1: After the first - side sintering of the porcelain chips to be sintered and the copper foil in the sintering furnace is completed, a single - sided copper - clad substrate is obtained. The single - sided copper - clad substrate is transferred to a rack made of a material with a low coefficient of friction for ultrasonic water washing.

[0009] Step 2: The single - sided copper - clad substrate and the copper foil after ultrasonic water washing are subjected to second - side sintering.

[0010] In this application, by screening the material of the insertion rack, a material with a low friction coefficient is finally selected. Thus, during the cleaning process, the material with a low friction coefficient plays a lubricating role for the single-sided copper-clad substrate, reducing the friction and wear between the insertion rack and the single-sided copper-clad substrate, and preventing the occurrence and expansion of cracks due to thermal stress after sintering.

[0011] Further preferably, the ultrasonic water washing is three-stage ultrasonic water washing, and pure water is used for cleaning.

[0012] Further preferably, the time for each stage of ultrasonic water washing is 3 - 5 min, and the temperature is 25 - 35 °C.

[0013] Further preferably, the material with a low friction coefficient is plastic or polyetheretherketone resin.

[0014] Further preferably, the material with a low friction coefficient is polyetheretherketone resin.

[0015] Further preferably, when sintering the first side and the second side, the belt speed of the conveyor belt inside the sintering furnace is 100 mm / min - 160 mm / min.

[0016] Further preferably, the temperature during the first-side sintering is 1070 - 1075 °C; the temperature during the second-side sintering is 1064 - 1071 °C.

[0017] Further preferably, when the ceramic chip to be sintered and the copper foil are sintered on the first side, they sequentially pass through four heating zones, four constant-temperature zones, and three cooling zones;

[0018] The four heating zones are sequentially set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C;

[0019] The total length of the heating zone is 1000 - 1200 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the heating zone is 9 - 15 min;

[0020] The passing times through the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0021] The four constant-temperature zones are set at temperatures between 1070 - 1075 °C; the total length of the constant-temperature zone is 1300 - 1500 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the constant-temperature zone is 14 - 18 min;

[0022] The three cooling zones are sequentially set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C;

[0023] The total length of the cooling zone is 1000 - 1100 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the cooling zone is 9 - 13 min.

[0024] Further preferably, when the single-sided copper-clad substrate and the copper foil are sintered on the second side, they sequentially pass through four heating zones, four constant-temperature zones, and three cooling zones;

[0025] The four heating zones are respectively set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C;

[0026] The total length of the heating zones is 1000 - 1200 mm; the time for the single-sided copper-clad substrate and the copper foil to pass through the heating zones is 9 - 15 min;

[0027] The passing times of the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0028] The temperatures of the four constant-temperature zones are set between 1064 - 1071 °C; the total length of the constant-temperature zones is 1300 - 1500 mm; the time for the single-sided copper-clad substrate and the copper foil to pass through the constant-temperature zones is 14 - 18 min;

[0029] The three cooling zones are respectively set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C;

[0030] The total length of the cooling zones is 1000 - 1100 mm; the time for the single-sided copper-clad substrate and the copper foil to pass through the cooling zones is 9 - 13 min.

[0031] Further preferably, the temperature of the constant-temperature zone during the second-side sintering is 4 - 6 °C lower than that during the first-side sintering. Since the bonding of copper during the sintering of the ceramic chip to be sintered and the copper foil mainly occurs in the constant-temperature zone, the further expansion of cracks is prevented by reducing the temperature of the constant-temperature zone.

[0032] The beneficial effects of the present invention are as follows: By selecting polyether ether ketone resin with a low coefficient of friction as the socket, it plays a lubricating role for the single-sided copper-clad substrate during the cleaning process, reduces the friction and wear between the socket and the single-sided copper-clad substrate, and prevents the occurrence and expansion of cracks due to thermal stress after sintering. The single-sided copper-clad substrate that has completed the first-side sintering is subjected to three-stage ultrasonic water washing and then the second-side sintering. During the sintering, the temperature of the constant-temperature zone is reduced to prevent the further expansion of cracks during sintering and improve the product yield. Description of the Drawings

[0033] Figure 1 It is a physical diagram of the DCB substrate in Embodiment 1 of the present invention;

[0034] Figure 2This is a physical diagram of the DCB substrate in Comparative Example 1 of the present invention. Detailed implementation mode

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0036] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present invention.

[0037] At the same time, it should be understood that for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0038] In addition, for the sake of clarity and conciseness, the description of well-known structures, functions, and configurations may be omitted. Those of ordinary skill in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of the present disclosure.

[0039] The technologies, methods, and devices known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorization specification.

[0040] In all the examples shown and discussed here, any specific value should be construed as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0041] Embodiment 1

[0042] A method for reducing porcelain cracking of a DCB substrate includes the following steps:

[0043] (1) Sintering on the first side: Place the sintered ceramic chip and copper foil in a sintering furnace for sintering on the first side. The sintering temperature is 1070 - 1075 °C, and the belt speed of the internal conveyor belt of the sintering furnace is 100 mm / min - 160 mm / min. The sintered ceramic chip and copper foil sequentially pass through four heating zones, four constant temperature zones, and three cooling zones;

[0044] The four heating zones are sequentially set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C;

[0045] The total length of the heating zone is 1000 - 1200 mm; the time for the sintered ceramic chip and copper foil to pass through the heating zone is 9 - 15 min;

[0046] The passing times of the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0047] The temperatures of the four constant temperature zones are set between 1070 - 1075 °C; the total length of the constant temperature zone is 1300 - 1500 mm; the time for the sintered ceramic chip and copper foil to pass through the constant temperature zone is 14 - 18 min;

[0048] The three cooling zones are sequentially set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C;

[0049] The total length of the cooling zone is 1000 - 1100 mm; the time for the sintered ceramic chip and copper foil to pass through the cooling zone is 9 - 13 min, and a single-sided copper-clad substrate is obtained.

[0050] (2) Three-stage ultrasonic water washing: Transfer the single-sided copper-clad substrate with the first side sintered to a rack made of polyether ether ketone resin (PEEK) and perform ultrasonic water washing in pure water.

[0051] Among them, the time for the first-stage ultrasonic water washing is 3 min and the temperature is 25 °C;

[0052] The time for the second-stage ultrasonic water washing is 4 min and the temperature is 30 °C;

[0053] The time for the third-stage ultrasonic water washing is 5 min and the temperature is 35 °C.

[0054] (3) Sintering of the second side: Place the single-sided copper-clad substrate and copper foil after the three-stage ultrasonic water washing in a sintering furnace for sintering the second side. The sintering temperature is 1064 - 1071 °C, and the belt speed of the internal conveyor belt of the sintering furnace is 100 mm / min - 160 mm / min. When sintering the second side, it sequentially passes through four heating zones, four constant temperature zones, and three cooling zones;

[0055] The four heating zones are sequentially set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C;

[0056] The total length of the heating zone is 1000 - 1200 mm; the time for the single-sided copper-clad substrate and copper foil to pass through the heating zone is 9 - 15 min;

[0057] The passing times of the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0058] The temperatures of the four constant-temperature zones are set between 1064 and 1071 °C; the total length of the constant-temperature zones is 1300 - 1500 mm; the time for the single-sided copper-clad substrate and copper foil to pass through the constant-temperature zones is 14 - 18 min;

[0059] The three cooling zones are successively set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C;

[0060] The total length of the cooling zones is 1000 - 1100 mm; the time for the single-sided copper-clad substrate and copper foil to pass through the cooling zones is 9 - 13 min.

[0061] For the physical picture of the DCB substrate finished product after sintering on the second side, refer to Figure 1 。

[0062] Example 2

[0063] A method for reducing porcelain cracking of DCB substrates, comprising the following steps:

[0064] (1) Sintering on the first side: Place the porcelain chip to be sintered and copper foil in a sintering furnace for sintering on the first side. The sintering temperature is 1070 - 1075 °C, and the belt speed of the internal conveyor belt of the sintering furnace is 100 mm / min - 160 mm / min. The porcelain chip to be sintered and copper foil successively pass through four heating zones, four constant-temperature zones, and three cooling zones;

[0065] The four heating zones are successively set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C;

[0066] The total length of the heating zones is 1000 - 1200 mm; the time for the porcelain chip to be sintered and copper foil to pass through the heating zones is 9 - 15 min;

[0067] The passing times of the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0068] The temperatures of the four constant-temperature zones are set between 1070 - 1075 °C; the total length of the constant-temperature zones is 1300 - 1500 mm; the time for the porcelain chip to be sintered and copper foil to pass through the constant-temperature zones is 14 - 18 min;

[0069] The three cooling zones are successively set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C;

[0070] The total length of the cooling zones is 1000 - 1100 mm; the time for the porcelain chip to be sintered and copper foil to pass through the cooling zones is 9 - 13 min, obtaining a single-sided copper-clad substrate.

[0071] (2) Tertiary ultrasonic water washing: Transfer the single-sided copper-clad substrate after the first-sided sintering to a rack made of plastic (PVC) material and perform ultrasonic water washing in pure water.

[0072] Among them, the time for the primary ultrasonic water washing is 3 min and the temperature is 25 °C;

[0073] The time for the secondary ultrasonic water washing is 4 min and the temperature is 30 °C;

[0074] The time for the tertiary ultrasonic water washing is 5 min and the temperature is 35 °C.

[0075] (3) Second-sided sintering: Place the single-sided copper-clad substrate and copper foil after the tertiary ultrasonic water washing into a sintering furnace for second-sided sintering. The sintering temperature is 1064 - 1071 °C, and the belt speed of the internal conveyor belt in the sintering furnace is 100 mm / min - 160 mm / min. When performing the second-sided sintering, it passes through four heating zones, four constant-temperature zones, and three cooling zones in sequence;

[0076] The four heating zones are sequentially set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C;

[0077] The total length of the heating zones is 1000 - 1200 mm; the time for the single-sided copper-clad substrate and copper foil to pass through the heating zones is 9 - 15 min;

[0078] The passing times through the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0079] The four constant-temperature zones are set at temperatures between 1064 - 1071 °C; the total length of the constant-temperature zones is 1300 - 1500 mm; the time for the single-sided copper-clad substrate and copper foil to pass through the constant-temperature zones is 14 - 18 min;

[0080] The three cooling zones are sequentially set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C;

[0081] The total length of the cooling zones is 1000 - 1100 mm; the time for the single-sided copper-clad substrate and copper foil to pass through the cooling zones is 9 - 13 min.

[0082] Example 3

[0083] A method for reducing porcelain cracking of DCB substrates, comprising the following steps:

[0084] (1) First - side sintering: Place the ceramic chip to be sintered and the copper foil in a sintering furnace for first - side sintering. The sintering temperature is 1070 - 1075 °C, the belt speed of the internal conveyor belt of the sintering furnace is 100 mm / min - 160 mm / min, and the ceramic chip to be sintered and the copper foil pass through four heating zones, four constant - temperature zones, and three cooling zones in sequence;

[0085] The four heating zones are sequentially set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C;

[0086] The total length of the heating zones is 1000 - 1200 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the heating zones is 9 - 15 min;

[0087] The passing times through the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0088] The four constant - temperature zones are set at temperatures between 1070 - 1075 °C; the total length of the constant - temperature zones is 1300 - 1500 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the constant - temperature zones is 14 - 18 min;

[0089] The three cooling zones are sequentially set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C;

[0090] The total length of the cooling zones is 1000 - 1100 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the cooling zones is 9 - 13 min, and a single - sided copper - clad substrate is obtained.

[0091] (2) Three - stage ultrasonic water washing: Transfer the single - sided copper - clad substrate and copper foil after the first - side sintering to a rack made of polyether ether ketone resin (PEEK) and perform ultrasonic water washing in pure water.

[0092] Among them, the time for the first - stage ultrasonic water washing is 3 min, and the temperature is 25 °C;

[0093] The time for the second - stage ultrasonic water washing is 4 min, and the temperature is 30 °C;

[0094] The time for the third - stage ultrasonic water washing is 5 min, and the temperature is 35 °C.

[0095] (3) Second - side sintering: Place the single - sided copper - clad substrate and copper foil after the three - stage ultrasonic water washing in a sintering furnace for second - side sintering. The difference in the conditions during sintering from the first - side sintering is only that the temperature of the constant - temperature zone is 1050 - 1063 °C.

[0096] Example 4

[0097] A method for reducing ceramic cracking of a DCB substrate, comprising the following steps:

[0098] (1) First - side sintering: Place the ceramic wafer to be sintered and the copper foil in a sintering furnace for first - side sintering. The sintering temperature is 1070 - 1075 °C, and the belt speed of the internal conveyor belt of the sintering furnace is 100 mm / min - 160 mm / min. The ceramic wafer to be sintered and the copper foil pass through four heating zones, four constant - temperature zones, and three cooling zones in sequence.

[0099] The four heating zones are set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C respectively;

[0100] The total length of the heating zones is 1000 - 1200 mm; the time for the ceramic wafer to be sintered and the copper foil to pass through the heating zones is 9 - 15 min;

[0101] The passing times through the four heating zones are 3 - 4.5 min, 3 - 4.5 min, 3 - 4.5 min, and 3 - 4.5 min in sequence;

[0102] The four constant - temperature zones are set at temperatures between 1070 - 1075 °C; the total length of the constant - temperature zones is 1300 - 1500 mm; the time for the ceramic wafer to be sintered and the copper foil to pass through the constant - temperature zones is 14 - 18 min;

[0103] The three cooling zones are set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C respectively;

[0104] The total length of the cooling zones is 1000 - 1100 mm; the time for the ceramic wafer to be sintered and the copper foil to pass through the cooling zones is 9 - 13 min, and a single - sided copper - clad substrate is obtained.

[0105] (2) Three - stage ultrasonic water washing: Transfer the single - sided copper - clad substrate after the first - side sintering to a rack made of plastic material (PVC) and perform ultrasonic water washing in pure water.

[0106] Among them, the time for the first - stage ultrasonic water washing is 3 min, and the temperature is 25 °C;

[0107] The time for the second - stage ultrasonic water washing is 4 min, and the temperature is 30 °C;

[0108] The time for the third - stage ultrasonic water washing is 5 min, and the temperature is 35 °C.

[0109] (3) Second - side sintering: Place the single - sided copper - clad substrate and the copper foil after the three - stage ultrasonic water washing in a sintering furnace for second - side sintering. The difference in the conditions during sintering from the first - side sintering is only that the temperature of the constant - temperature zone is 1050 - 1063 °C.

[0110] Example 5

[0111] Example 5 is basically the same as Example 1, except that in Example 5, the temperature of the constant temperature zone during the second-side sintering is the same as that of the constant temperature zone during the first-side sintering.

[0112] Comparative Example 1

[0113] This Comparative Example 1 is basically the same as Example 1, except that in Comparative Example 1, the single-sided copper-clad substrate after the first-side sintering is placed in a rack made of stainless steel material for cleaning operation. For the physical picture of the finished DCB substrate after sintering, refer to Figure 2 。

[0114] Comparative Example 2

[0115] This Comparative Example 2 is basically the same as Comparative Example 1, except that in Comparative Example 3, the conditions for the second-side sintering are the same as those for the first-side sintering.

[0116] Take the same number of DCB substrates after sintering in Examples 1-4 and Comparative Examples 1-2, and observe the porcelain cracking situation on both sides of the DCB substrate manually, as shown in Table 1 below:

[0117] Table 1 Comparison table of porcelain cracking in DCB substrates in examples and comparative examples

[0118] Sample Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Porcelain cracking ratio 0 0.8％ 0.05％ 1％ 1％ 1.5％ 2％

[0119] As can be seen from Table 1, by comparing Examples 1-4 with Comparative Examples 1 and 2, after using a rack made of a material with a low coefficient of friction to place the single-sided copper-clad substrate after the first-side sintering for cleaning, the porcelain cracking ratio of the DCB substrate in the examples is always lower than that in the comparative examples; at the same time, by comparing Example 1, Example 3 and Example 5, Example 2 and Example 4, Comparative Example 1 and Comparative Example 2 respectively, when the temperature of the constant temperature zone during the second-side sintering is between 1064 and 1071 °C in the rack made of a material with a low coefficient of friction, it is beneficial to prevent the further expansion of cracks, thereby improving the product yield.

[0120] The above are only the preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to be equivalent embodiments within the scope of the technical solution of the present invention. However, as long as it does not depart from the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still belong to the scope of the technical solution of the present invention.

Claims

1. A method for reducing porcelain cracking of a DCB substrate, characterized in that, It includes the following steps: Step 1: After the first side of the ceramic chip to be sintered and the copper foil are sintered in the sintering furnace, a single-sided copper-clad substrate is obtained, and the single-sided copper-clad substrate is transferred to a holder made of a material with a low coefficient of friction for ultrasonic water washing. Step 2: The second side of the single-sided copper-clad substrate and the copper foil after ultrasonic water washing are sintered.

2. A method for reducing porcelain cracking of a DCB substrate according to claim 1, characterized in that, The ultrasonic water washing is three-stage ultrasonic water washing, and pure water is used for cleaning.

3. A method for reducing porcelain cracking of a DCB substrate according to claim 1, characterized in that, The time for each stage of ultrasonic water washing is 3 - 5 minutes, and the temperature is 25 - 35 °C.

4. A method for reducing porcelain cracking of a DCB substrate according to claim 1, characterized in that, The material with a low coefficient of friction is plastic or polyether ether ketone resin.

5. A method for reducing porcelain cracking of a DCB substrate according to claim 4, characterized in that, The material with a low coefficient of friction is polyether ether ketone resin.

6. A method for reducing porcelain cracking of a DCB substrate according to claim 4, characterized in that, When sintering the first side and the second side, the belt speed of the internal conveyor belt of the sintering furnace is 100 mm / min - 160 mm / min.

7. A method for reducing porcelain cracking of a DCB substrate according to claim 4, characterized in that, The temperature during the first side sintering is 1070 - 1075 °C; the temperature during the second side sintering is 1064 - 1071 °C.

8. A method for reducing porcelain cracking of a DCB substrate according to claim 7, characterized in that, When the ceramic chip to be sintered and the copper foil are sintered on the first side, they sequentially pass through four heating zones, four constant temperature zones, and three cooling zones. The four heating zones are sequentially set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C. The total length of the heating zone is 1000 - 1200 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the heating zone is 9 - 15 minutes. The passing times of the four heating zones are 3 - 4.5 minutes, 3 - 4.5 minutes, 3 - 4.5 minutes, and 3 - 4.5 minutes in sequence. The four constant temperature zones are set at temperatures between 1070 - 1075 °C; the total length of the constant temperature zone is 1300 - 1500 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the constant temperature zone is 14 - 18 minutes. The three cooling zones are sequentially set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C. The total length of the cooling zone is 1000 - 1100 mm; the time for the ceramic chip to be sintered and the copper foil to pass through the cooling zone is 9 - 13 minutes.

9. A method for reducing porcelain cracking of a DCB substrate according to claim 7, characterized in that, When the single-sided copper-clad substrate and the copper foil are sintered on the second side, they sequentially pass through four heating zones, four constant temperature zones, and three cooling zones. The four heating zones are sequentially set at temperatures between 600 - 700 °C, 700 - 850 °C, 850 - 960 °C, and 850 - 1050 °C. The total length of the heating zone is 1000 - 1200 mm; the time for the single-sided copper-clad substrate and the copper foil to pass through the heating zone is 9 - 15 minutes. The passing times of the four heating zones are 3 - 4.5 minutes, 3 - 4.5 minutes, 3 - 4.5 minutes, and 3 - 4.5 minutes in sequence. The four constant temperature zones are set at temperatures between 1064 - 1071 °C; the total length of the constant temperature zone is 1300 - 1500 mm; the time for the single-sided copper-clad substrate and the copper foil to pass through the constant temperature zone is 14 - 18 minutes. The three cooling zones are sequentially set at temperatures between 1025 - 1035 °C, 970 - 980 °C, and 920 - 930 °C. The total length of the cooling zone is 1000 - 1100 mm; the time for the single-sided copper-clad substrate and the copper foil to pass through the cooling zone is 9 - 13 minutes.

10. A method for reducing porcelain cracking of a DCB substrate according to claim 9, characterized in that, The temperature of the constant temperature zone during the sintering of the second side is 4 to 6 °C lower than that of the constant temperature zone during the sintering of the first side.

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