Ceramic scribing substrate, method for manufacturing ceramic scribing substrate, method for manufacturing ceramic substrate, and method for manufacturing ceramic circuit substrate

Abstract

The invention provides a ceramic scribing substrate which has few burrs and notches during segmentation and can obtain a plurality of ceramic scribing substrates. The ceramic scribing substrate is provided with edge scribing lines and corner scribing lines, and auxiliary scribing lines which intersect with intersection points along the edge scribing lines are formed near the intersection points of the corner scribing lines and the edge scribing lines. The auxiliary cutting line has a length of 0.5 mm or more and 15.0 mm or less, and the edge cutting line and the auxiliary cutting line are formed by dots.

Description

Technical Field

[0001] The implementation methods generally involve ceramic etched substrates, methods for manufacturing ceramic etched substrates, methods for manufacturing ceramic substrates, and methods for manufacturing ceramic circuit boards. Background Technology

[0002] In recent years, with the development of semiconductor devices requiring high current, such as power electronics and next-generation power semiconductors, the demand for ceramic substrates that combine heat dissipation and electrical insulation has been increasing year by year. In particular, with miniaturization and high performance, and as the heat generated by the devices increases, there is a tendency for the thickness of ceramic substrates to become thinner in order to achieve efficient heat dissipation. On the other hand, in order to reduce the manufacturing cost of ceramic substrates, processes are being carried out to manufacture them in larger shapes. Regarding silicon nitride substrates with high strength, high toughness and high heat dissipation among ceramic substrates, a substrate with a size of 220mm × 220mm × 0.32mm has been disclosed (Patent Document 1).

[0003] To efficiently manufacture ceramic substrates, a method is employed that involves manufacturing large ceramic substrates and dividing them into product sizes. In silicon nitride substrates, which possess both high strength and high thermal conductivity, a division method utilizing laser scribing has been disclosed (Patent Documents 2 and 3). According to Patent Document 2, by deepening the scribing holes and reducing the spacing, the generation of burrs and the like can be suppressed. Furthermore, according to Patent Document 3, a rectangular silicon nitride-based ceramic scribing substrate with chamfered corners at its four outer corners can be divided into product shapes.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 6399252 Patent Document 2: Japanese Patent Application Publication No. 2008-198905 Patent Document 3: Japanese Patent No. 6990360 Summary of the Invention

[0005] The problem that the invention aims to solve On the other hand, in order to reduce the manufacturing cost of ceramic substrates, new challenges have emerged from laser processing of large and thin ceramic substrates. For example, if a single substrate is to be obtained from a large silicon nitride substrate by laser processing, a large force is required to break (segment) it along the scribing lines to achieve high strength, thus requiring the laser to penetrate deep into the thickness direction of the silicon nitride substrate. However, if the silicon nitride substrate is thin, the possibility of it being segmented due to the processing steps after the laser scribing lines are formed and the forces applied during handling increases. Conversely, if the laser is penetrated shallower along the thickness direction of the silicon nitride substrate, the possibility of segmentation during intermediate processes is lower, but a large force is required to break it, which can sometimes create a workload and cause notches and cracks on the outer periphery due to the large force applied.

[0006] Furthermore, the problems arising from chamfering the ceramic substrate that constitutes the ceramic scriber substrate have become clear. Even when conventional ceramic scribers have chamfered portions, the scribe lines in the chamfered portions are formed in the same shape as the other scribe lines. Therefore, the smaller chamfered portions of thinner and stronger ceramic substrates are difficult to break, as described above. Sometimes, the chamfered portions do not break and remain on the substrate, resulting in reduced yield and workability.

[0007] The implementation method is designed to address such problems by reducing the likelihood of residual cracks on the ceramic substrate during fracture and by reducing the generation of burrs and notches during fracture.

[0008] Methods for solving problems The ceramic scribed substrate of the embodiment is a ceramic scribed substrate having edge scribed lines and corner scribed lines. Near the intersection of the corner scribed line and the edge scribed line, an auxiliary scribed line is formed that intersects the intersection along the edge scribed line.

[0009] According to an embodiment, a method for manufacturing a ceramic scribing substrate is provided, characterized in that edge scribing lines, corner scribing lines, and auxiliary scribing lines are formed by using laser irradiation to form dots on the ceramic scribing substrate of the embodiment.

[0010] According to an embodiment, a method for manufacturing a ceramic substrate is provided, characterized in that the ceramic substrate is manufactured by applying stress to the ceramic scribed substrate of the embodiment and dividing it along the scribed lines.

[0011] According to an embodiment, a method for manufacturing a ceramic circuit board is provided, characterized in that it includes the method for manufacturing a ceramic circuit board as described in the embodiment. Ceramic circuit boards are manufactured by bonding metal circuits onto a ceramic substrate.

[0012] According to an embodiment, a method for manufacturing a ceramic circuit board is provided, characterized in that a metal circuit is bonded on the ceramic scribed substrate of the embodiment. Ceramic circuit boards are manufactured by applying stress to a ceramic scribed substrate with metal circuits and dividing it along the scribed lines. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating an example of a ceramic scribed substrate with scribed lines according to an embodiment.

[0014] Figure 2 This is a schematic diagram illustrating an example of a ceramic substrate obtained by dividing the ceramic scribed substrate of the embodiment.

[0015] Figure 3 This is a schematic diagram illustrating an example of an implementation method with edge and corner scribing lines.

[0016] Figure 4 It means in Figure 3 A schematic diagram of an example with auxiliary scribing lines.

[0017] Figure 5 This is a schematic diagram illustrating an example of extending the scribing lines in an embodiment.

[0018] Figure 6 This is a schematic diagram illustrating an example of forming the corner scribe lines of an embodiment as continuous grooves.

[0019] Figure 7 This is a schematic diagram illustrating an example of setting the corner scribed lines of an embodiment in a curved manner.

[0020] Figure 8A It means Figure 4 An enlarged view of the first example in section A.

[0021] Figure 8B It means Figure 4 An enlarged view of the second example in section A.

[0022] Figure 8C It is along Figure 8B The cross-sectional view of the auxiliary scribing lines of the ceramic scribing substrate shown is cut off by the CC line.

[0023] Figure 9 This is a side view showing an example of a ceramic circuit board according to an embodiment.

[0024] Figure 10 This is a side view showing an example of a ceramic circuit board integrated by a resin mold according to an embodiment.

[0025] Figure 11 It means Figure 1A schematic diagram of an example of the dots of the scribing lines on a ceramic scribing substrate.

[0026] Figure 12 It will include Figure 11 The scribed line shows a cross-sectional view of the substrate portion cut along XII-XII.

[0027] Figure 13 It means from Figure 11 A top view near the end of a ceramic substrate segmented by a ceramic scribed substrate.

[0028] Figure 14 It means Figure 12 A cross-sectional view of a portion of the points shown in the scribed lines.

[0029] Figure 15 It means using laser to Figure 14 A cross-sectional view of an example of a point that has undergone further processing.

[0030] Figure 16 This is a schematic diagram showing the ceramic scribed substrate with scribed lines in Embodiments 1 and 9. Detailed Implementation

[0031] Hereinafter, with reference to the accompanying drawings, embodiments of the ceramic scribed substrate, the ceramic substrate, the method for manufacturing the ceramic scribed substrate, the method for manufacturing the ceramic substrate, and the method for manufacturing the ceramic circuit board will be described in detail.

[0032] The ceramic scribed substrate of this embodiment is a ceramic scribed substrate having edge scribed lines and corner scribed lines. Near the intersection of the corner scribed line and the edge scribed line, an auxiliary scribed line is formed that intersects the intersection along the edge scribed line. Here, "near the intersection of the corner scribed line and the edge scribed line" refers to any position including the intersection of the corner scribed line and the edge scribed line. Therefore, the ceramic scribed substrate of this embodiment has an auxiliary scribed line formed at any position including the intersection of the corner scribed line and the edge scribed line, intersecting the intersection along the edge scribed line. The auxiliary scribed line may be formed at the same position as the edge scribed line, or for example, as shown in the example... Figure 8A , Figure 8B As shown, the auxiliary scribing line can be formed at a position offset from the edge scribing line, or at a position that does not overlap with the edge scribing line. If the auxiliary scribing line intersects the intersection point along the edge scribing line, it is also possible to form the auxiliary scribing line at a position that is not the same as the intersection point (in a way that overlaps with the intersection point).

[0033] Figure 1This diagram schematically illustrates an example of a ceramic scribed substrate (hereinafter referred to as "scribed substrate") with scribed lines. The scribed substrate 1 has a total of 16 ceramic substrates 2, four in each direction and four in each direction, which will become the product. Peripheral portions 5, which are not part of the product, are formed around the ceramic substrates 2. The scribed lines forming the ceramic substrates 2 and the peripheral portions 5 are edge scribed lines 3. Figure 1 In the middle, two longitudinal and two transverse outer edge scribe lines (hereinafter referred to as "outer edge scribe lines") are formed on the outer side of the peripheral portion 5. Additionally, three longitudinal and three transverse inner edge scribe lines 32 are formed on the inner side of the outer edge scribe lines 31. Corner scribe lines 4 are formed around the ceramic substrate 2 to create a chamfer. Figure 1 In the peripheral portion 5, the outer corner scribe lines (hereinafter referred to as "outer corner scribe lines") extend into the interior of the peripheral portion 5. On the other hand, the terminals of the inner corner scribe lines (hereinafter referred to as "inner corner scribe lines") that do not reach the peripheral portion 5 connect with the edge scribe lines 3. The implementation is not limited to this shape; a single ceramic substrate can be processed into a product shape using scribe lines, or multiple processing operations with more than two scribe lines in both directions can be performed. Furthermore, it is not necessary to form scribe lines throughout the entire perimeter of the ceramic substrate; one or more scribe lines are sufficient. Additionally, in... Figure 1 In a top view, it appears as a rectangular shape with chamfered corners of equal size, but it can also be roughly polygonal. Furthermore, Figure 2 The ceramic substrate 2 is obtained by breaking the scribed substrate 1, and has a chamfered portion 6 formed thereon.

[0034] Figure 3 This diagram schematically illustrates the edge scribe lines 3 and inner corner scribe lines 41 surrounded by the ceramic substrate 2. Figure 3 In the middle, the inner corner indentation line 41 is not formed beyond the edge indentation line 3. Additionally, in... Figure 3 The diagram shows an interior corner scribe line 41 without auxiliary scribe lines. The ceramic substrate 2 is obtained by breaking along the edge scribe line 3 of the scribe substrate 1. Furthermore, a chamfered portion 6 is formed by breaking along the corner scribe line 4.

[0035] Figure 4 This diagram schematically illustrates the state after the edge indentation line 3 and the interior angle indentation line 41 have been formed, and the auxiliary indentation line 7 has been formed. Figure 4In this diagram, auxiliary scribing lines 7 are indicated by black circles to distinguish them from edge scribing lines 3. Near the intersection of the inner corner scribing line 41 and the edge scribing line 3, auxiliary scribing lines 7 are formed along the edge scribing line 3 and intersecting at the intersection point. When edge scribing lines 3 and inner corner scribing lines 41 are formed by laser processing, increasing the dot spacing improves machinability. However, if the dot spacing at the intersection of the edge scribing line 3 and the inner corner scribing line 41 is wide, a sharp-angle force is applied, preventing sharp breakage and resulting in burrs. Therefore, by forming auxiliary scribing lines along the edge scribing line 3, the portion with the auxiliary scribing lines is easier to break, suppressing burrs generated when breaking at the intersection of the edge scribing line 3 and the inner corner scribing line 41. Furthermore, since the auxiliary scribing lines 7 are formed on a portion of the edge scribing line 3, unnecessary breakage of the edge scribing line 3 due to applied force in subsequent processes is prevented. It should be noted that in... Figure 4 In the middle, at the intersection of the two ends of the inner corner scribed line 41 and the edge scribed line 3, there is an auxiliary scribed line 7 that intersects the intersection along the edge scribed line 3. However, an auxiliary scribed line 7 that intersects the intersection can also be formed at the intersection of one of the two intersections.

[0036] Figure 5 This diagram schematically illustrates the state in which chamfered outer corner markings 42 are formed on the peripheral portion 5. (Example) Figure 5 As shown, if it is not used for the peripheral part 5 of the product, the corner scribe line can be extended to form an extension 43. This is because, for chamfered parts that are small and difficult to apply force to when breaking, by providing an extension 43 on the outer corner scribe line 42, the corner scribe line becomes longer and force can be applied, making it easier to break.

[0037] The internal corner scribing line 41 and the auxiliary scribing line 7 can also be formed by continuous grooves instead of points. If formed by continuous grooves, it can reduce the generation of crack residue and burrs, but the cost-effectiveness is poor. Therefore, the internal corner scribing line 41 and the auxiliary scribing line 7 are preferably formed by points.

[0038] Figure 6 This is a schematic diagram showing the corner scribe line 4 formed by a continuous groove 44 instead of a point. As mentioned above, forming a continuous groove is disadvantageous in terms of cost-effectiveness, but if the chamfer becomes smaller, it is difficult to apply force to the fractured part at a point, which easily leads to burr defects. Therefore, when the chamfer is less than 1 mm in, for example, C-chamfers and R-chamfers, it is preferable to form the corner fracture line by a continuous groove 44.

[0039] It should be noted that the corner engraving line 4 can also be... Figures 3-6 The recorded straight line. Alternatively, it could be... Figure 7 The recorded curve. Figure 7 The 45° scribed line is curved, which can form an R-shaped chamfer.

[0040] Furthermore, it is preferable that the corner scribe line 4 is formed before the auxiliary scribe line 7 is set. By forming the corner scribe line 4 first, the positional offset is small, and the auxiliary scribe line 7 can be formed, thus shortening the auxiliary scribe line 7. The length of the formed auxiliary scribe line 7 is preferably 0.5 mm or more and 15 mm or less at each location. If it is less than 0.5 mm, the effect of setting the auxiliary scribe line 7 may not be fully achieved. On the other hand, if it is longer than 15 mm, the effect of setting the auxiliary line remains the same, but the processing time increases, and the production efficiency may decrease. Therefore, the length of the auxiliary scribe line 7 is more preferably 2 mm or more and 13 mm or less, and even more preferably 4 mm or more and 11 mm or less.

[0041] Figure 8A yes Figure 4 An enlarged view of the first example in section A. Figure 8A In the middle, the center point of the edge inscription line does not overlap with the center point of the auxiliary inscription line. Figure 8A In this context, the distance Lx is defined as the distance from the point on the edge scribe line 3 to the right-angle direction, extending to the straight line passing through the center point of the auxiliary scribe line 7. Preferably, the distance Lx between the edge scribe line 3 and the auxiliary scribe line 7 is parallel, but if they are not parallel, it is defined as the distance between the points where the edge scribe line 3 and the auxiliary scribe line 7 are furthest apart. In this case, the distance Lx between the auxiliary scribe line 7 and the edge scribe line 3 is preferably set to within 100 μm. If the auxiliary scribe line 7 moves away from the edge scribe line 3, the effect of the break at the auxiliary intersection point becomes smaller, and burr defects are generated due to the separation. Therefore, it is more preferable to be within 50 μm, and even more preferably within 25 μm.

[0042] exist Figure 8B In this design, the distance between the points of the edge engraving line 3 is set as L, and the distance between the point of the auxiliary engraving line 7 and the point of the edge engraving line 3 is set as Ly. Preferably, the point of the auxiliary engraving line 7 is located at 1 / 4 to 3 / 4 of the spacing width L of the edge engraving lines 3. The point of the auxiliary engraving line 7 being located at 1 / 4 means that the point of the auxiliary engraving line 7 is formed by dividing the points of the edge engraving line 3 into four equal parts and shifting them by 1 / 4. This is because if the point of the auxiliary engraving line 7 is located far from the points of the edge engraving lines, the points of the auxiliary engraving line 7 and the edge engraving line 3 are prone to aligning and breaking along the lines. Therefore, it is preferable to be located at 1 / 3 to 2 / 3 of the distance L between the points of the edge engraving line 3. Furthermore, it is more preferable to be located at 1 / 2 of the distance L between the points of the edge engraving line 3. The 1 / 2 position means that the point of the auxiliary engraving line 7 is located in the central part where the points of the edge engraving line 3 are divided in two. Here, the distance L between points refers to the distance between point-like holes, but it is defined as the distance obtained by comparing the average distance between points along a scribed line. Therefore, there may be parts that do not meet the stated conditions.

[0043] Figure 8C It is a general representation of what will Figure 8B The diagram shows a cross-sectional view of the edge scribe line 3, which has an auxiliary scribe line 7, cut along the CC line in the scribe substrate shown. Point 3a of the edge scribe line 3 and point 7a of the auxiliary scribe line 7 are both inverted conical recesses. At the location where a portion of point 7a of the auxiliary scribe line 7 overlaps with a portion of point 3a of the edge scribe line 3, there is a concave-convex shape with a recess corresponding to point 3a and a recess corresponding to point 7a connected to each other.

[0044] Furthermore, the depth of the auxiliary scribing line 7 is preferably greater than the depth of the edge scribing line 3. This is because the intersection of the auxiliary scribing line 7 and the edge scribing line 3 is more prone to breakage, and therefore the deeper side is more likely to break. More preferably, the depth of the auxiliary scribing line 7 is 1.5 times or more the depth of the edge scribing line 3. In this case, it is also possible to scribing through both the front and back surfaces of the substrate 1. In addition, the corner scribing line 4 can also be processed in a manner that forms a through groove. Furthermore, the auxiliary scribing line 7 can also be provided in other locations, making the provided location easy to divide.

[0045] Furthermore, in contrast to a corner scribing line, there can be one or two auxiliary scribing lines. On the other hand, since the auxiliary scribing lines are formed along the areas where edge scribing lines are formed, the groove width of the laser scribing line at the areas where auxiliary scribing lines are formed may be wider than other areas within the same edge scribing line. As a result, microscopic height differences are generated when viewed from the laser-processed surface. Therefore, it is preferable that the auxiliary scribing lines be shorter at the locations where the ceramic substrates are in contact with each other. The locations where the ceramic substrates are in contact with each other refer to, for example... Figure 1 The area indicated by the inner corner scribing line 41.

[0046] Furthermore, it is preferable that the inner corner scribe line 41 in the scribe substrate does not have an extension, while the outer corner scribe line 42 has an extension 43. The length of the extension 43 is preferably 0.1 mm or more and 8 mm or less. More preferably, the length of the extension is 0.2 mm or more and 5 mm or less. If it is shorter than 0.1 mm, the corner scribe line cannot reach the area of ​​the auxiliary scribe line, which may result in defects during slitting. On the other hand, if it is longer than 8 mm, when the scribe line breaks along the edge, the area near the edge of the corner scribe line may be finely sliced ​​into individual pieces.

[0047] Furthermore, regarding the length of the edge markings 3, parallel edge markings can be of the same length or different lengths. Preferably, the two sets of four outer edge markings 31 adjacent to the peripheral portion 5 are longer than the inner edge markings 32 that exist parallel to them. More preferably, the inner edge markings 32 have outer edge markings 31 that are perpendicularly connected to them, and preferably have an exposed portion 33 extending outward from the point of intersection with the perpendicularly connected outer edge markings 31 to the outer periphery, which is 0.1 mm or more and 8 mm or less. If the length of the exposed portion 33 is shorter than that of the outer edge markings 31, the processing time can be shortened.

[0048] The laser used for processing the edge scribing lines 3 and corner scribing lines 4 is preferably any one of a YAG laser (fundamental or second harmonic), a fiber laser, an excimer laser, a semiconductor laser, or a CO2 laser. Furthermore, the wavelength of the laser used is preferably 500 nm or more and 1100 nm or less. A fiber laser or a YAG laser is more preferred. A fiber laser is even more preferred. Using a fiber laser allows for stable output and high efficiency processing, and is therefore preferred. Furthermore, fiber lasers can process fine and deep scribing lines. Additionally, when processing with a laser, it is preferable to place the substrate on a stage and perform laser processing by moving the stage.

[0049] Furthermore, the laser oscillation mode is preferably either continuous mode or pulsed mode. Particularly when using pulsed mode oscillation, a pulse width of picoseconds or less is preferred. A pulse width of picoseconds or less facilitates fine machining, and is therefore preferred.

[0050] In addition, auxiliary gas can be used as needed, and dust collection can also be implemented. By collecting dust, it is possible to prevent the generated dust from adhering to and covering the laser irradiation port.

[0051] The ceramic substrate 2 is preferably any one of a silicon nitride substrate, an aluminum nitride substrate, and an alumina substrate. Alternatively, an Alusil high-silicon heat-resistant aluminum alloy substrate can be used as an alumina substrate. The Alusil high-silicon heat-resistant aluminum alloy is a sintered body with 20-80 wt% zirconium oxide remaining relative to alumina. The three-point flexural strength of the aluminum nitride substrate or the alumina substrate is approximately 300-450 MPa. The strength of the Alusil high-silicon heat-resistant aluminum alloy substrate is also approximately 550 MPa. The three-point flexural strength of the silicon nitride substrate can be increased to over 600 MPa, and further to over 700 MPa. Furthermore, the thermal conductivity of the silicon nitride substrate can be increased to over 50 W / m·K, and further to over 80 W / m·K. In recent years, silicon nitride substrates that combine both high strength and high thermal conductivity have also been developed.

[0052] Furthermore, the ceramic substrate is preferably a substrate for being divided into multiple pieces. When the ceramic substrate is divided into multiple pieces, the ceramic substrate is preferably rectangular with a short side of 10 cm or more and a long side of 20 cm or more. As described above, if the ceramic substrate being processed is large, more ceramic substrates can be obtained from a single scriber substrate. Therefore, the divided ceramic substrates can be obtained efficiently.

[0053] Furthermore, the thickness of the ceramic substrate is preferably 0.1 mm or more and 2 mm or less. If the thickness exceeds 2 mm, processing may be time-consuming. On the other hand, if the thickness is less than 0.1 mm, sufficient strength may not be guaranteed. A more preferred thickness of the ceramic substrate is 0.2 mm or more and 1 mm or less. If the thickness of the ceramic substrate is 0.2 mm or more and 1 mm or less, processing can be carried out efficiently while maintaining sufficient strength, and therefore this is preferred.

[0054] Furthermore, the resulting etched substrate preferably undergoes a surface cleaning process in subsequent processes, such as honing or sandblasting.

[0055] It can form a ceramic circuit board by bonding metal circuits such as metal plates to a ceramic substrate 2 that has been divided by laser processing. Figure 9 An example of a ceramic circuit board 8 according to an embodiment is shown. Figure 9 In the diagram, 8 is a ceramic circuit board, 2 is a ceramic substrate, 9 is a metal circuit, and 10 is a metal heat sink.

[0056] The metal plate used for the metal circuit 9 can include Cu (copper), copper alloys, Al (aluminum), etc. The ceramic substrate 2 and the metal circuit 9 are preferably bonded via a bonding layer (not shown in the figure). Furthermore, bonding via a bonding layer is also preferred when bonding a metal heat sink. Additionally, it is preferable to provide a bonding layer between the ceramic substrate 2 and the metal circuit 9 using an active metal solder containing an active metal such as Ti (titanium). Besides Ti, Zr (zirconium) can also be listed as an active metal solder. As an active metal solder, besides Ti, mixtures with Ag (silver) or Cu as the main component can also be listed. Furthermore, Ti is 0.1 wt% or more and 10 wt% or less, Cu is 10 wt% or more and 60 wt%, and Ag is the remainder. Additionally, as needed, 1 wt% or more and 15 wt% or less of one or more selected from In (indium), Sn (tin), Al, Si (silicon), C (carbon), and Mg (magnesium) can be added. An active metal solder paste is coated on the surface of the ceramic substrate 2 using an active metal soldering method, and the metal circuit 9 is disposed thereon. They are joined by heating to a temperature above 600°C and below 900°C. According to the active metal bonding method, the bonding strength between the ceramic substrate 2 and the metal circuit 9, which is a copper circuit board, can be 16 kN / m or more.

[0057] Alternatively, a metal thin film with one of the following as its main components—Ni (nickel), Ag (silver), or Au (gold)—can be disposed on the surface of the metal circuit 9. Examples of such metal thin films include plating and sputtering films. By disposing of a metal thin film, corrosion resistance and solder wettability can be improved.

[0058] Furthermore, the conductor portion is preferably joined before the ceramic substrates are scribing the substrate. In this case, the joined conductor portion is preferably a copper or aluminum component with excellent thermal conductivity. Copper or aluminum components refer to copper or copper alloys, or aluminum or aluminum alloys. Alternatively, conductor portions with a predetermined shape can be joined beforehand during the joining of the conductors. When the process of setting the conductor portion is based on the joining of metal plates, the joined metal plates are preferably subjected to processes such as etching or chemical polishing in subsequent processes.

[0059] Such a ceramic circuit board 8 is suitable for semiconductor modules characterized by mounting semiconductor elements on a metal circuit 9 via a bonding layer.

[0060] Figure 10 An example of a semiconductor module (semiconductor device) according to an embodiment is shown in the figure. Figure 10 In the diagram, 8 is the ceramic circuit board, 11 is the semiconductor module, 12 is the lead bonding, 13 is the semiconductor element, 14 is the resin mold, and 15 is the lead frame.

[0061] exist Figure 10 In this process, a semiconductor element 13 is bonded to the metal circuit 9 of the ceramic circuit substrate 8 via a bonding layer (not shown). Similarly, a lead frame 15 is bonded via a bonding layer (not shown). Adjacent metal circuits 9 are connected to each other via lead bonding 12. Figure 10 In addition to the semiconductor element 13, the wire bond 12 is also bonded to the metal circuit 9. The semiconductor module 11 is formed by integrating the ceramic circuit substrate 8 with the wire bond 12 connected by the resin mold 14. The semiconductor module 11 is not limited to this structure. For example, the wire bond 12 and the lead frame 15 can be either one. In addition, multiple semiconductor elements 13, wire bonds 12 and lead frames 15 can be respectively provided in the metal circuit 9.

[0062] Additionally, the bonding layer that joins the semiconductor element 13 and the lead frame 15 can include solder, brazing filler metal, etc. Lead-free solder is preferred. Furthermore, solder refers to solder with a melting point below 450°C. Brazing filler metal refers to brazing filler metal with a melting point above 450°C. Brazing filler metal with a melting point above 500°C is also called high-temperature brazing filler metal. Examples of high-temperature brazing filler metals include those with Ag as the main component.

[0063] While miniaturization of semiconductor elements 13 is progressing, heat generation from the chips is also increasing. Therefore, improving heat dissipation in the ceramic circuit board 8 housing the semiconductor elements 13 becomes crucial. Furthermore, to achieve high performance in the semiconductor module 11, multiple semiconductor elements 13 are mounted on the ceramic circuit board 8. If even a single semiconductor element 13 exceeds its intrinsic temperature, the temperature coefficient changes to the negative side of the resistance. This can lead to thermal runaway and instantaneous damage due to concentrated power flow. Therefore, improving heat dissipation is essential. Additionally, the semiconductor module 11 can be used in PCU, IGBT, and IPM modules in inverters for automobiles (including electric vehicles), electric railway vehicles, industrial machinery, and air conditioning systems. Regarding automobiles, electric vehicles are becoming increasingly common. Improving the reliability of the semiconductor module 11 is directly related to vehicle safety. The same applies to electric railway vehicles and industrial equipment.

[0064] Next, the laser marking method for the silicon nitride substrate in the ceramic marking substrate 1 of the embodiment will be described. The manufacturing method of the silicon nitride substrate is not particularly limited as long as it has the aforementioned configuration; however, the following methods can be listed as methods for obtaining good yield.

[0065] First, a silicon nitride substrate is prepared. In particular, considering the overall heat dissipation of the ceramic circuit board 8 formed from the silicon nitride substrate, it is preferable that the thermal conductivity of the silicon nitride substrate is 50 W / m·K or higher and the three-point bending strength is 600 MPa or higher.

[0066] Furthermore, when establishing the connection between the metal circuit 9 and the metal heat sink 10, a silicon nitride substrate with through holes is prepared. If through holes are provided on the silicon nitride substrate, they can also be provided beforehand during the forming stage. Alternatively, a process of providing through holes within the silicon nitride sintered body can be performed. The process of providing through holes is performed using laser processing, cutting processing, or the same methods as laser marking. Cutting processing is performed using drilling tools or similar methods.

[0067] A silicon nitride substrate is placed on the precision machining stage of a laser processing machine. The substrate is irradiated with a laser to form edge scribing lines 3, corner scribing lines 4, and auxiliary scribing lines 7. At this time, depending on the conditions of the laser processing machine, dots or continuous grooves of specified dimensions are formed.

[0068] Next, stress is applied to the silicon nitride substrate, which serves as the ceramic scribing substrate 1, and the ceramic scribing substrate 1 is divided along the scribing line 3, thereby manufacturing one or more ceramic substrates 2.

[0069] Next, the metal circuit 9 is bonded to the silicon nitride substrate, which serves as the ceramic substrate 2. The bonding between the silicon nitride substrate and the metal circuit 9 is preferably performed using an active metal bonding method. The active metal bonding method uses an active metal solder mixed with an active metal such as Ti. Examples of active metal solders include mixtures of Ti, Ag, and Cu, for example, where Ti is 0.1 wt% or more and 10 wt% or less, Cu is 10 wt% or more and 60 wt% or less, and Ag is the remainder. Additionally, depending on the requirements, one or more elements selected from In, Sn, Al, Si, C, and Mg may be added at 1 wt% or more and 15 wt% or less.

[0070] The active metal solder is pasteurized. The paste is made by mixing the solder components with organic matter, but the solder components need to be uniformly mixed. This is because if the solder components are not uniformly distributed, the brazing will be unstable and result in poor bonding.

[0071] An active metal solder paste is applied to a ceramic substrate 2. A copper plate is then placed on it. Next, a process is performed to bond the substrate by heating it to a temperature between 600°C and 900°C. The heating process can be performed in a vacuum or a non-oxidizing atmosphere, depending on the requirements. Alternatively, when performed in a vacuum, a temperature of 1×10⁻⁶ is preferred. -2 Below Pa. Additionally, non-oxidizing atmospheres include nitrogen and argon atmospheres. By using a vacuum or non-oxidizing atmosphere, oxidation of the bonding layer can be suppressed. This, in turn, improves the bonding strength.

[0072] The bonded metal circuit 9 can be either a circuit pre-patterned for circuit formation or an unpatterned board. Alternatively, when using a single board, etching is performed after bonding to create a pattern. This process enables the manufacture of a silicon nitride metal circuit board as a ceramic circuit board substrate 8.

[0073] Next, a process of bonding semiconductor elements 13, etc., is performed. A bonding layer is provided at the location where the semiconductor element 13 is bonded. Solder or brazing filler metal is preferably used for the bonding layer. The bonding layer is provided, and the semiconductor element 13 is provided thereon. In addition, if necessary, the lead frame 15 is bonded via the bonding layer. In addition, if necessary, lead bonding 12 is provided. In addition, the required number of semiconductor elements 13, lead frames 15, and lead bonding 12 are provided. The silicon nitride circuit board with semiconductor elements 13, lead frames 15, and lead bonding 12 is integrated into a resin mold 16, thereby sealing the interior.

[0074] The above describes the manufacture of the ceramic circuit board 8 by bonding metal circuits 9, etc., to a ceramic substrate 2 after it has been divided from the ceramic scribed substrate 1, but it is not limited to this method. For example, it can also be manufactured by bonding metal circuits 9, etc., to the ceramic substrate 2 before it is divided in the ceramic scribed substrate, and then applying stress to the ceramic scribed substrate 1 with the metal circuits 9, etc., and dividing it along the scribed lines. That is, the order of the dividing process of the ceramic scribed substrate 1 and the bonding process of the metal circuits 9, etc. is not limited. Alternatively, a metal plate such as a copper plate can be bonded to the ceramic substrate 2 before it is divided in the ceramic scribed substrate, and the metal circuits 9 can be formed by etching or other processing. It is also possible to apply stress to the ceramic scribed substrate 1 with the metal circuits 9, etc., thus obtained, and divide it along the scribed lines.

[0075] The laser marking method for the aluminum nitride substrate in the ceramic marking substrate 1 of the embodiment will be described. First, an aluminum nitride substrate is prepared. In particular, considering the overall heat dissipation of the circuit board, it is preferable to have a thermal conductivity of 170 W / m·K or higher and a three-point bending strength of 350 MPa or higher. As long as the laser marking of the aluminum nitride substrate has the aforementioned configuration, its manufacturing method is not particularly limited. As a method for obtaining good yield, the same manufacturing process as that for the silicon nitride substrate and silicon nitride circuit board described above is used.

[0076] Reference Figures 11-15 The shape of the dots of the scribing lines provided on the ceramic scribing substrate of the embodiment will be described. Figure 11 This is represented by the edge engraving line 3 and the auxiliary engraving line 7. Figure 1 An example of a point on the scribed line. Figure 12 This indicates that it will contain Figure 11 The scribed section is a cross-sectional view of the substrate portion cut along line XII-XII. Figure 13 This is an enlarged top view of the end of the ceramic substrate 2, which is divided from the ceramic scribed substrate 1 along the scribed lines. Figure 14 It means Figure 12 A cross-sectional view of a portion of the point shown. Figure 15 It means using laser to... Figure 14 The figures show cross-sectional views of examples of reprocessing the points shown. In each figure, the thickness direction of the ceramic scribed substrate 1 or ceramic substrate 2 is defined as parallel to the z-axis direction. Furthermore, the main surface of the ceramic scribed substrate 1 or ceramic substrate 2 is defined as parallel to the xy-plane.

[0077] like Figure 11 As shown, dots 101 are spaced apart on the ceramic scriber substrate 1 to form scribe lines 100. The scribe lines 100 can be represented by edge scribe lines 3 and auxiliary scribe lines 7. Figure 1 Any of the types of scribed lines shown. For example... Figure 12As shown, point 101 is a concave part in the shape of an inverted cone. The shape of the concave part of point 101 is not limited to an inverted cone shape. For example, it can be an inverted pyramid shape, a cylinder shape, a prism shape, or the bottom of the above-listed shapes can be a shape with a curved surface (such as a U-shaped shape or a hemispherical shape).

[0078] If Figure 11 and Figure 12 The ceramic substrate 1 with scribe lines 100 shown is divided along scribe lines 100 to obtain one or more ceramic substrates 2. In this case, point 101 is divided into two along the z-axis. The result is as follows: Figure 13 As shown, the ceramic substrate 2 has some or all of its recesses and protrusions at the end of its main surface. The recess 102, for example, has a shape that is approximately semi-circular when viewed from one of the main surfaces of the ceramic substrate 2, and its area decreases along the thickness direction z.

[0079] When scribing lines 100 are formed on the ceramic scribing substrate 1 by laser processing, for example, Figure 14 Point 101 is shown. If laser processing is performed again at the location where point 101 is formed, the depth of point 101 can be increased. Figure 15 An example is shown. Point 103 has the same inverted conical shape as point 101, but its depth is deeper than that of point 101. Furthermore, the size, depth, shape, and other morphology of the points constituting the scribe lines can vary depending on the performance of the laser processing apparatus, the laser processing conditions, and the type of ceramic substrate.

[0080] (Examples 1-13, Comparative Examples 1-5) As shown in Table 1, 100 ceramic scribing substrates (assembly substrates) of 140mm × 270mm (14cm × 27cm) and 110mm × 220mm (11cm × 22cm) were prepared. The types of ceramic substrates included silicon nitride substrates, aluminum nitride substrates, alumina substrates, and Alusil high-silicon heat-resistant aluminum alloy substrates. The thermal conductivity of the silicon nitride substrate was 90 W / m·K, and its three-point bending strength was 650 MPa. The thermal conductivity of the aluminum nitride substrate was 170 W / m·K, and its three-point bending strength was 350 MPa. The thermal conductivity of the alumina substrate was 25 W / m·K, and its three-point bending strength was 400 MPa. The thermal conductivity of the Alusil high-silicon heat-resistant aluminum alloy substrate was 25 W / m·K, and its three-point bending strength was 650 MPa. Figure 1As shown, edge scribing lines are formed by creating four vertically × four horizontally oriented ceramic substrates with a 10mm perimeter. When the overall size of the ceramic scribing substrate (assembly substrate) is 140mm × 270mm (14cm × 27cm), the size of each ceramic substrate is 30mm × 62.5mm. Alternatively, when the overall size of the ceramic scribing substrate (assembly substrate) is 110mm × 220mm (11cm × 22cm), the size of each ceramic substrate is 22.5mm × 5mm. Next, corner scribing lines are applied to the ceramic substrates. The intersection points of all corner scribing lines and edge scribing lines are designed to be at the same position. Table 1 shows the shapes of the corner scribing lines. Figure 4 In cases where the angular markings are straight lines, they are recorded as straight lines. Figure 7 In cases where the shape is curved, it is recorded as a curve. Furthermore, Examples 1-13 are provided with auxiliary scribing lines, while Comparative Examples 1-5 are not provided with auxiliary scribing lines.

[0081] In Examples 2 to 8 and Examples 10 to 12, as follows Figure 1 As shown, an edge marking line 31 is provided with a length extending to the edge, and is configured such that it protrudes 1 mm or more but less than 7 mm from the intersection of the edge of other edge marking lines 32 and the edge marking line 31 towards the outer periphery. Furthermore, in Embodiments 1 and 9, auxiliary marking lines are provided, such as... Figure 16 As shown, the edge scribing line 32 is configured such that its length from the intersection point to the outer periphery is more than 1 mm and less than 7 mm, as shown in Figure 13. Additionally, Example 13 includes auxiliary scribing lines, such as... Figure 5 As shown, the corner scribing line is made to protrude more than 1mm and less than 7mm from the intersection with the edge scribing line to the outer periphery 43.

[0082] In contrast, in Comparative Example 1, the lengths of the edge scribing lines 31 and 32 are all implemented in a manner from edge to edge, and the corner scribing lines 41 and 42 are also implemented in a manner from edge to edge, without setting auxiliary scribing lines. In Comparative Example 2, no auxiliary scribing lines are set, and the corner scribing line 42 is set to a length 43 that extends slightly beyond the outer perimeter from the intersection with the edge scribing line.

[0083] Each scribing line was formed using a fiber laser. The dots constituting the scribing lines have an inverted conical shape with a diameter of 0.1 mm and a depth of 0.1 mm. Furthermore, the size and shape of the dots are appropriately adjusted according to the performance of the equipment used in laser processing, the laser processing conditions, and the type of ceramic substrate, and are not limited to the size and shape of the embodiments. The scribing substrates of the embodiments and comparative examples were divided using a fracture device. The cases where the corners could not be broken due to the device's fracture and remained as a defect rate were defined as corner scribing line defects. The cases where the peripheral areas could not be broken due to the device's fracture and remained as a defect rate were defined as edge scribing line defects. Additionally, the corner scribing line defects and edge scribing line defects were broken off using a jig, and all the divided ceramic substrates were observed. The cases where burrs and notches were observed were defined as burr / notch defects. The respective defect rates are shown in Table 2.

[0084] In Examples 1-13, the defect rates of corner scribing lines, edge scribing lines, and burrs / notches were all low. This is because by setting auxiliary scribing lines, the generation of burrs and notches can be suppressed, and the fracture residue of edge and corner scribing lines can be reduced.

[0085] In contrast, in Comparative Examples 1-5, the defect rates for corner scribing, edge scribing, and burrs / gap defects were all high. Furthermore, numerous burrs and gaps were observed at the intersection of the edge and corner scribing. This is because, in the scribing lines set in this embodiment and the comparative examples, there were no auxiliary scribing lines, resulting in areas that were difficult to break remaining at the intersection of the corner and edge scribing.

[0086] Based on the above results, it can be seen that by adding auxiliary scribing lines near the intersection of the edge scribing lines and the corner scribing lines, multiple ceramic scribing substrates with fewer burrs and gaps can be obtained efficiently during the dicing process.

[0087] The above embodiments of the present invention have been illustrated, but these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These variations of the embodiments are included in the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents. Furthermore, the above embodiments can be combined with each other for implementation.

[0088] Explanation of reference numerals in the attached figures 1… Ceramic scribed substrate, 2… Ceramic substrate, 3… Edge scribed line, 31… Outer edge scribed line, 32… Inner edge scribed line, 33… Exposed portion, 4… Corner scribed line, 41… Inner corner scribed line, 42… Outer corner scribed line, 43… Extension portion, 44… Continuous groove, 5… Peripheral portion, 6… Chamfered portion, 7… Auxiliary scribed line, 8… Ceramic circuit board, 9… Metal circuit, 10… Metal heat sink, 11… Semiconductor module, 12… Lead bonding, 13… Semiconductor element, 14… Resin mold, 15… Lead frame.

Claims

1. A ceramic scribing substrate, characterized in that, It is a ceramic scribing substrate with edge scribing lines and corner scribing lines. In particular, near the intersection of the corner indentation line and the edge indentation line, there are auxiliary indentation lines that intersect the intersection along the edge indentation line.

2. The ceramic scribing substrate according to claim 1, characterized in that, The length of the auxiliary scribing lines is 0.5 mm or more and 15.0 mm or less.

3. The ceramic scribing substrate according to claim 1 or 2, characterized in that, The edge incised lines and auxiliary incised lines are formed by points.

4. The ceramic scribing substrate according to claim 3, characterized in that, The center point of the edge scribing line does not overlap with the center point of the auxiliary scribing line.

5. The ceramic scribing substrate according to claim 1 or 2, characterized in that, The ceramic scribed substrate is a silicon nitride substrate, an aluminum nitride substrate, or an aluminum oxide substrate.

6. A method for manufacturing a ceramic scribing substrate, characterized in that, Edge scribing lines, corner scribing lines, and auxiliary scribing lines are formed by using laser irradiation to form dots on the ceramic scribing substrate as described in claim 1 or 2.

7. A method for manufacturing a ceramic substrate, characterized in that, A ceramic substrate is manufactured by applying stress to the ceramic scribed substrate as described in claim 1 or 2 and dividing it along the scribed lines.

8. A method for manufacturing a ceramic circuit board, characterized in that, It includes the method for manufacturing the ceramic substrate as described in claim 7, and, Ceramic circuit boards are manufactured by bonding metal circuits onto a ceramic substrate.

9. A method for manufacturing a ceramic circuit board, characterized in that, Metal circuitry is bonded on the ceramic scribed substrate as described in claim 1 or 2, and, Ceramic circuit boards are manufactured by applying stress to a ceramic scribed substrate with metal circuits and dividing it along the scribed lines.

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