A method of dicing a ceramic substrate

Abstract

The application discloses a ceramic substrate slicing method, which comprises the following steps: controlling the scratch line depth in the range of 50% to 60% of the thickness of the ceramic substrate; adding a row of blank circuit substrates on the original ceramic substrate; designing a ceramic substrate slicing tool based on the bending principle; and slicing the ceramic substrate by first slicing the whole plate and then slicing small pieces, so that the final product is obtained. The new scratch line depth can meet the production line production needs and ensure the substrate quality; the new ceramic substrate slicing tool is designed to assist the product slicing, so that the uncontrollability of manual slicing is replaced, the product surface device is better protected, and the product quality and production efficiency in the slicing operation are improved. After the improved and optimized process is used in production, the production efficiency is improved by more than 55%, and the product qualified rate is improved to more than 98%.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuits, and specifically relates to a method for wafering ceramic substrates. Background Technology

[0002] With the strict implementation of national carbon emission standards, the new energy vehicle industry and related sectors are booming, the market size is expanding, and demand is growing exponentially. Ceramic integrated circuits are widely used in the front-end heat treatment system control of new energy vehicles (traditional vehicles), and the market demand for commercial core chip control circuits is huge.

[0003] In current general technologies, the slab fabrication process for ceramic integrated circuits suffers from low efficiency, significant issues with multiple or missing ceramic wafers, and negatively impacts product performance and appearance.

[0004] During production, this series of products uses a 2mm thick ceramic substrate, resulting in a large overall board size (sheet size: 112.2×96.8mm; single product size: 14.15×12.4×2mm), a large number of sheets, and a large number of components on the product surface with significant differences in component size and type. This makes sheet separation difficult during production, leading to significant issues with uneven ceramic mounting after separation. Furthermore, the sheet separation process can easily damage components mounted on both sides, thus affecting circuit performance. Summary of the Invention

[0005] This invention provides a method for slicing ceramic substrates. Through technological innovation and process improvement, it aims to solve the slicing process of 2mm thick ceramic substrates, optimize and improve the product process technology, achieve large-scale mass production, and meet product performance and appearance requirements.

[0006] A method for slicing ceramic substrates is characterized by controlling the depth of the scratch line within the range of 50% to 60% of the thickness of the ceramic substrate; adding a blank circuit board to the original ceramic substrate; designing a ceramic substrate slicing fixture that utilizes the bending principle; and the slicing process involves first slicing the entire plate individually, and then slicing it into smaller pieces to obtain the final product.

[0007] Furthermore, the process of slitting the entire plate separately is as follows: taking the side where the blank substrate is located as the top, first remove the process edges on the bottom, left, and right sides to reduce the force applied during slitting, retaining the top blank substrate part, inserting the blank substrate end into the groove of the fixed shaft and the rotating shaft, aligning the substrate scratch line with the bending point of the tooling, and manually pushing the rotating shaft of the tooling to obtain the strip-shaped product; when inserting the blank substrate into the groove of the fixed shaft and the rotating shaft, it should not be inserted from top to bottom, but should be inserted horizontally from left to right or from right to left, and the product should be kept stable after the rotating shaft rotates and bends to avoid large-scale shaking.

[0008] Furthermore, the process of slitting into smaller pieces is as follows: the slitting product is inserted into the grooves of the fixed shaft and the rotating shaft with the direction of the solder pad as the bottom insertion direction. Ensure that one end of the product is against the tooling limit point, so that the scratch line on the substrate is aligned and coincides with the bending point of the tooling. After confirming that the foolproof photoelectric switch has no alarm, step on the cylinder control switch to push the rotating shaft downward and bend it with the force cylinder, and the final product can be obtained.

[0009] Furthermore, in the segmentation step, the angle of rotation when the rotating axis bends downward is within the range of 5°±1°.

[0010] Furthermore, the ceramic substrate must be subjected to uniform force when it is sliced ​​on the tooling.

[0011] Furthermore, when the rotating shaft bends downwards, the assist spring will give it an upward thrust, assisting the rotating shaft to spring back and return to the same horizontal position as the fixed shaft.

[0012] A ceramic substrate slicing fixture is characterized by comprising a fixed shaft and a rotating shaft, both of which are fixed on a fixture base. The fixed shaft is provided with a boss, and the rotating shaft is provided with a groove adapted to the boss. The fixed shaft and the rotating shaft are fitted together by the boss and the groove. The fixed shaft is provided with a fixed shaft groove, and the rotating shaft is provided with a rotating shaft groove. When the fixed shaft groove and the rotating shaft groove are fitted together, there is a herringbone-shaped notch.

[0013] A force-applying cylinder, an assist spring, and a foolproof photoelectric switch are also fixed on the tooling base; a cylindrical contact device is added to the top of the force-applying cylinder rod to make soft contact with the rotating shaft; one end of the assist spring is fixed on the rotating shaft, and the other end is fixed on the spring base; the foolproof photoelectric switch is fixed on the rotating shaft through a foolproof photoelectric switch mounting bracket; the direction of the assist spring's rebound force forms a 45° angle with the direction of the rod's push force.

[0014] The present invention has the following beneficial effects:

[0015] In the process optimization and improvement of product slab separation, the following measures were taken: First, a new scribing line depth was set to meet the production line needs and ensure substrate quality; second, the substrate circuit layout was redesigned to improve the quality of slab-separated products; and third, new tooling was designed to assist in product slab separation, replacing the uncontrollability of manual slab separation, better protecting the surface components of the product, and improving product quality and production efficiency in the slab separation process. After using the improved and optimized process in production, production efficiency increased by more than 55%, and the product qualification rate increased to over 98%. This process has been widely used in mass production, and both product quality and production efficiency have been improved. Attached Figure Description

[0016] Figure 1 This is a full-page product illustration;

[0017] Figure 2 This is a schematic diagram of the slit product;

[0018] Figure 3 This is a schematic diagram showing the location of the front pads;

[0019] Figure 4 This is a schematic diagram showing the location of the pads on the back side;

[0020] Figure 5 This is a schematic diagram of the slitting tooling as a whole;

[0021] Figure 6 This is a diagram illustrating the striping process;

[0022] Figure 7 This is a schematic diagram of the overall segmented tooling;

[0023] Figure 8 This is a schematic diagram of the segmented rotation combination;

[0024] Figure 9 This is a schematic diagram of the piecework tooling operation;

[0025] Figure 10 This is a schematic diagram of a fixed shaft;

[0026] Figure 11 Schematic diagram of the rotating shaft;

[0027] Figure 12 This is a schematic diagram of the groove on the rotating shaft;

[0028] Figure 13 This is a schematic diagram of the fixed shaft groove;

[0029] Figure 14 This is a schematic diagram showing the direction of force application of the assist spring;

[0030] Explanation of reference numerals: 1-Tooling base, 2-Force-applying cylinder, 3-Rotating shaft, 4-Fixed shaft, 5-Rotating shaft groove, 6-Fixed shaft groove, 7-Assist spring, 8-Spring base, 9-Footproof photoelectric switch, 10-Footproof photoelectric switch mounting base, 11-Cylindrical contact device. Detailed Implementation

[0031] The invention will now be described in detail with reference to the accompanying drawings.

[0032] Ceramic integrated circuits have surface mount devices on both sides, and there are a large number of them. Some of these devices are thicker than the substrate. Therefore, during the dicing process, the protruding devices are easily damaged. Furthermore, due to the physical properties of ceramic materials, the edges of the substrate after dicing may have raised or recessed surfaces, i.e., more or less ceramic. This phenomenon can affect the compatibility and safety of the product and pose certain potential electrical performance risks.

[0033] After the product components are mounted and reflowed, the main process of product slab separation is to separate the continuous substrate into small finished pieces. The subsequent lead insertion process requires connecting the pads on the front and back of the product, which must be done in small pieces. Therefore, the slab separation process is crucial, and the quality of slab separation directly determines the product quality and production pass rate.

[0034] To ensure the quality of product slabs and improve the production pass rate, process improvements and enhancements were made to three key aspects of product slab slabs: 1. Substrate scratch lines; 2. Substrate process layout; 3. Three-part slab slab method; detailed explanations are provided below.

[0035] 1. Substrate Scratch Lines

[0036] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, the scratch lines on the product substrate are created using laser technology according to design requirements. Their purpose is to facilitate substrate cracking during slicing. Therefore, the depth of the scratch lines determines the ease of slicing and the occurrence of excess or insufficient ceramic. Taking a 2mm thick ceramic substrate as an example, when the scratch lines are shallower, the force required for slicing is greater. Greater force results in a greater release of force at the moment of substrate separation, leading to more severe ceramic chipping. Based on this principle, when the scratch line is 50% (1mm), the force required during slicing is greater, resulting in more instances of insufficient ceramic and a lower product yield. When the scratch line is 70% (1.4mm), slicing is easier, and the occurrence of excess or insufficient ceramic is less common, but the initial circuit printing and solder paste printing can cause substrate cracking, resulting in substrate waste. After multiple tests of the scratch line, the best balance was finally achieved by controlling the scratch line depth within the range of 50% to 60% of the ceramic substrate thickness. This means that circuit printing and solder paste printing will not cause the substrate to crack, and the working condition is intact. There is less chipping of ceramic tiles, and the tile condition is optimal.

[0037] II. Substrate Process Layout

[0038] The process layout of a product mainly refers to the distribution of circuits on the substrate. During the slicing process, stress is released at the moment the substrate cracks, and this stress release is the main cause of ceramic chipping. Therefore, the process layout of the substrate is designed with corresponding circuit distributions according to different slicing steps and directions to achieve the optimal slicing state. In a full-coverage state, the process edges of the substrate are removed first during the slicing operation, which is more suitable for slicing. However, because there is no force buffer after removing the process edges, and the slicing state is long and thin, the force release at the very end of the slicing process is the greatest, making ceramic chipping most likely. If the process edges are not removed, there is a certain force release area during the slicing process, but the force required for slicing is greater. This is because the process edges are lateral and block the force transmission direction, meaning the slicing direction and the process edges are perpendicular to each other, increasing the difficulty of slicing.

[0039] After comprehensive consideration, the final solution adopted was to add a blank row of circuit boards, such as... Figure 1 , Figure 2 As shown, this increases the overall size of the substrate, providing a sufficient force release area during the slitting process to protect the integrity of the substrate. Secondly, removing the process edges beforehand during slitting minimizes the force applied during slitting and also facilitates substrate cracking. Furthermore, the added blank circuit board during slitting effectively concentrates areas with excess or insufficient ceramic, preventing damage to the normally printed circuit board and protecting the edge integrity of the substrate.

[0040] III. Segmentation Method

[0041] To reduce the problem of too much or too little ceramic during production and meet product design requirements, we first conducted manual segmentation tests using traditional methods. However, there are many components on the surface, and there are specific requirements for the perpendicularity of some components. Manual segmentation makes it easy to touch the components, which can lead to damage or falling off the components, thus affecting the electrical performance of the product.

[0042] Based on product requirements and existing processes, a ceramic substrate slicing fixture utilizing the bending principle was designed, with a cylinder providing power to assist in the slicing process. The primary design objective was to protect the integrity of the product substrate and components. Therefore, in the initial design phase, corresponding grooves were designed based on the distribution of components and the substrate thickness to ensure that components do not touch the slicing fixture during the slicing process. Secondly, the design addressed the issue of uneven ceramic distribution at the product edges. Stress analysis models revealed that uneven stress significantly contributed to this uneven distribution. Therefore, the fixture was designed to apply stress as evenly as possible during slicing.

[0043] like Figures 5-12As shown, a ceramic substrate slicing fixture includes a fixed shaft 4 and a rotating shaft 3. Both the fixed shaft 4 and the rotating shaft 3 are fixed on the fixture base 1. The fixed shaft 4 is provided with a boss, and the rotating shaft 3 is provided with a groove that adapts to the boss. The fixed shaft and the rotating shaft are fitted together by the boss and the groove. The fixed shaft is provided with a fixed shaft groove 6, and the rotating shaft is provided with a rotating shaft groove 5. When the fixed shaft groove 6 and the rotating shaft groove 5 are fitted together, there is a herringbone notch.

[0044] A force-applying cylinder 2 and a spring base 8 are also fixed on the tooling base 1; a cylindrical contact device 11 is installed on the top of the force-applying cylinder rod to make soft contact with the rotating shaft 3; one end of the assist spring 7 is fixed on the rotating shaft 3 and the other end is fixed on the spring base 8; the foolproof photoelectric switch 9 is fixed on the rotating shaft 3 through the foolproof photoelectric switch fixing seat 10.

[0045] The slicing process is divided into two parts: slicing the entire sheet into strips and slicing into smaller pieces. Since the length and width of the products are different, in order to ensure that the edges of the sliced ​​products are neat, they are first sliced ​​into strips independently, and then into smaller pieces, thus obtaining the final product.

[0046] like Figure 5 As shown, during the slitting process, the fixed shaft groove 6 and the rotating shaft groove 5 have the same dimensions and are mirror images of each other.

[0047] like Figure 8 As shown, when dividing into smaller pieces, the size of the fixed shaft groove 6 is larger than the size of the rotating shaft groove 5, and their positions are mirror images.

[0048] like Figure 6 As shown, the slitting process is as follows: Using a fulcrum bending method, with the direction of the solder pad as the bottom insertion direction and the side of the blank substrate as the top, first remove the process edges on the bottom, left, and right sides, retaining the top process edge (i.e., the blank substrate part). Insert the blank substrate end into the fixed shaft groove 6 and the rotating shaft groove 5, aligning the substrate scratch line with the bending point of the fixture. Using the bending principle, manually push the rotating shaft 3 of the fixture to obtain the strip-shaped product. It is important to note that when inserting into the fixed shaft groove 6 and the rotating shaft groove 5 with the solder pad end as the direction, it cannot be inserted from top to bottom. The irregularly shaped components on the back of the product have large protrusions, so it should be inserted horizontally from left to right or from right to left. After rotating and bending, the product must be kept stable to avoid large-scale shaking. This will greatly reduce the phenomenon of missing or insufficient ceramic at both ends of the slitting product.

[0049] like Figure 9As shown, the slicing process is as follows: Using a pneumatic bending method, the slicing process involves inserting the sliced ​​product into the fixed shaft groove 6 and the rotating shaft groove 5 with the direction of the solder pad as the bottom insertion direction. Ensure one end of the product is against the fixture limit, aligning the substrate scratch line with the bending point of the fixture. After confirming that the foolproof photoelectric switch 9 has no alarm, step on the cylinder control switch. The force-applying cylinder 2 pushes the rotating shaft 3 downwards to bend, thus obtaining the final product. When the rotating shaft 3 moves downwards, the assist spring 7 provides an upward thrust, assisting the rotating shaft 3 to rebound back to the same horizontal position as the fixed shaft 4. The direction of the assist spring's rebound force forms a 45° angle with the direction of the pneumatic rod's push force. Figure 14 As shown.

[0050] The most important thing in the slitting and slicing process is to reduce the presence of too much or too little ceramic in the slicing products and to ensure the dimensional integrity of the substrate.

[0051] During the slitting process, because the rotation point acts directly on the blank substrate, the substrate will crack due to stress as the slitting shaft rotates and the angle changes. The instantaneously released force extends upwards along the blank substrate, and the force transmission gradually decreases with distance. Therefore, the instantaneous force applied to the blank substrate is the greatest and will not damage the normal product. The remaining parts, due to the presence of the scratch lines, are directly decomposed during force transmission without damaging the substrate or components. In this way, phenomena such as missing ceramic or chipped edges during slitting are concentrated on the blank substrate, which helps protect the integrity of the product and the good condition of the components.

[0052] In the slab splitting process, the rotation angle of the tooling rotating shaft 3 when it bends is crucial. If the rotation angle is too small, the kinetic energy generated during product splitting cannot be dissipated in time, resulting in more obvious ceramic chipping. If the rotation angle is too large, the kinetic energy will be distributed at the edge of the substrate, causing severe ceramic chipping. Therefore, the rotation angle of the rotating shaft is set within the range of 5°±1° according to the product thickness.

Claims

1. A method for slicing ceramic substrates, characterized in that, The depth of the scratch line is controlled within 50% to 60% of the thickness of the ceramic substrate; a blank circuit board is added to the original ceramic substrate; a ceramic substrate slicing tooling based on the bending principle is designed; the slicing process adopts the method of first slicing the whole plate separately, and then slicing it into smaller pieces to obtain the final product. The ceramic substrate slicing fixture includes a fixed shaft (4) and a rotating shaft (3). Both the fixed shaft (4) and the rotating shaft (3) are fixed on the fixture base (1). The fixed shaft (4) has a boss, and the rotating shaft (3) has a groove that matches the boss. The fixed shaft (4) and the rotating shaft (3) are fitted together using the boss and the groove. The fixed shaft has a fixed shaft groove (6), and the rotating shaft has a rotating shaft groove (5). When the fixed shaft groove (6) and the rotating shaft groove (5) are fitted together, there is a herringbone notch. The base (1) is also fixed with a force-applying cylinder (2), an assist spring (7) and a foolproof photoelectric switch (9); the top of the rod of the force-applying cylinder (2) is equipped with a cylindrical contact device (11) that makes soft contact with the rotating shaft (3); one end of the assist spring (7) is fixed on the rotating shaft (3) and the other end is fixed on the spring base (8); the foolproof photoelectric switch (9) is fixed on the rotating shaft (3) through the foolproof photoelectric switch fixing seat (10); the direction of the rebound assist force of the assist spring (7) is at a 45° angle to the direction of the push force of the rod; The process of slitting the entire plate separately is as follows: taking the side where the blank substrate is located as the top, first remove the process edges of the bottom, left and right sides to reduce the force applied during slitting, retain the top blank substrate part, insert the blank substrate end into the fixed shaft groove (6) and the rotating shaft groove (5), align the substrate scratch line with the bending part of the tooling, push the tooling rotating shaft (3), and you can get the strip product; when inserting the blank substrate into the fixed shaft groove (6) and the rotating shaft groove (5), it should not be inserted from top to bottom, but should be inserted horizontally from left to right or from right to left, and the product should be kept stable after the rotating shaft (3) rotates and bends to avoid large-scale shaking; The process of slitting into smaller pieces is as follows: Insert the slitting product into the fixed shaft groove (6) and the rotating shaft groove (5) with the direction of the solder pad as the bottom insertion direction. Ensure that one end of the product is against the tooling limit position, so that the substrate scratch line and the tooling bend are aligned and coincident. Ensure that the foolproof photoelectric switch (9) has no alarm. Step on the cylinder control switch to push the rotating shaft (3) downward to bend by the force cylinder (2), and the final product can be obtained.

2. The ceramic substrate slab separation method as described in claim 1, characterized in that, In the segmentation step, when the rotating shaft (3) rotates downward and bends, the rotation angle is within the range of 5°±1°.

3. The ceramic substrate slab separation method as described in claim 2, characterized in that, When the rotating shaft (3) bends downward, the assist spring (7) will give it an upward thrust, assisting the rotating shaft (3) to rebound and return to the same horizontal position as the fixed shaft (4).

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