JP2001338806A - Ceramic plate board for chip resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic plate board for a chip resistor, in which the generation of defective cracking and defective division in the manufacturing process of the ceramic plate board and the chip resistor is inhibited and which can satisfy dimensional accuracy after division. SOLUTION: The depth in total of both main surfaces of primary split grooves 1 is made shallower than that of both main surfaces of secondary split grooves 2, and primary split grooves 1a on the resistance forming surface side are formed in size deeper than primary split grooves 1b on the rear side and secondary split grooves 2b on the rear side in size deeper than secondary split grooves 2a on the resistance forming surface side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ceramic substrate used as a base material for a chip resistor or the like.

[0002]

2. Description of the Related Art As shown in FIG.
In this device, electrodes 14 are formed on both main surfaces and end surfaces of a ceramic substrate 12, and a resistor 13 is formed on one of the main surfaces, and a protective film 15 is formed thereon. Conventionally, the ceramic substrate 12 is divided into a large number of in-grating regions 3 by the dividing grooves 6 as shown in FIG. 9, and the primary dividing groove 1 formed on the short side 3a of the in-grid region 3 and the long side. It has a secondary dividing groove 2 formed in 3b and is handled in this shape until the middle of the manufacturing process in order to manufacture the chip resistor 11 efficiently.

[0003] As chip resistors 11 have become smaller and have tighter dimensional accuracy, it has become common to form dividing grooves 6 at corresponding positions on both main surfaces.
As shown in FIG. 10, the dividing groove 6 is formed by pressing the blades 8a and 8b provided on the mold against the green sheet 5. By firing the green sheet 5 thus formed into a predetermined shape at a predetermined temperature, the ceramic substrate 12 is obtained.

Next, the manufacturing process of the chip resistor 11 will be described. As shown in FIG. 11, first, electrodes 14 are printed and fired on both main surfaces of the ceramic substrate 12, and then a resistor 13 is printed and fired on one main surface of the ceramic substrate 12.
Next, the resistance value is set by laser trimming and the resistance 13 is set.
A protective film 15 is printed and fired on the upper surface. Next, the primary division groove 1 is divided, and the electrode 14 is placed on the end face of the divided primary division groove 1.
After printing and baking, the chip resistor 11 is manufactured by dividing the secondary division groove 2.

As a conventional dividing method of the primary dividing groove 1 and the secondary dividing groove 2, a roller method and a folding method are well known, and the roller method is shown in FIG.
As shown in FIG. 13A, the ceramic substrate 12 is inserted and pressed between the large-diameter roller 16 and the small-diameter roller 17 so that the bar-shaped substrate 4 as shown in FIG.
This is a method of dividing into chip resistors 11 as shown in FIG. In the bending method, as shown in FIG. 12 (b), the ceramic substrate 12 is sandwiched by a pressing portion 18 and a bending force is applied by a split portion 19, so that the ceramic substrate 12 can be bared in the same manner as the roller method described above. This is a method of dividing into a substrate 4 or a chip resistor 11.

However, when the primary dividing groove 1 is divided, in the above-described roller system, the pressing force from the large-diameter roller 16 is applied to the secondary dividing groove 2 of the ceramic substrate 12 and the bar is broken up to the secondary dividing groove 2. There is also a problem that a bending failure occurs and the secondary division groove 2 is also broken by the pressing force holding the ceramic substrate 12 even in the anti-folding method. The bar breaking failure that occurs when the primary division groove 1 is divided and the secondary division groove 2 is broken interferes with the operation of the automatic machine in the process of printing the electrode 14 on the end face, such as conveyance, positioning, and printing. It is necessary to stop the automatic machine or remove broken defects.

Various proposals regarding the groove depth have been made in order to solve the problems such as the bar breaking failure.
In Japanese Patent No. 2889293, when dividing along a vertical groove (primary division groove 1) and then dividing along a horizontal groove (secondary division groove 2), the depth of the vertical groove is set to 0.5 of the substrate thickness T. It is shown that the lateral groove is formed as shallow as 0.2 to 0.3 of the substrate thickness T.

Although the thickness T of the substrate is not described in Japanese Patent Application Laid-Open No. 3-64089, the depth of the printing surface of the dividing groove 6 (primary dividing groove 1) in the first dividing direction is set to 170 to 260.
μm, the depth of the back surface is 10 to 120 μm, the depth of the printing surface of the division groove 6 (secondary division groove 2) in the last dividing direction is 10 to 100 μm, and the depth of the back surface is 70 to 180 μm. It is shown. This means that the total depth of both main surfaces of the secondary division groove 2 is shallower than the total depth of both main surfaces of the primary division groove 1,
In addition, the depth of the printing surface of the secondary dividing groove 2 is formed shallower than the back surface side, and the electrode 14, the resistor 13, and the protective film 15 are formed on the printing surface, so that the printing surface has a valley shape due to the tensile stress. Even if it is presented, the secondary division groove 2 is formed by applying a load to both ends of the ceramic substrate 12 when the primary division groove 1 is divided.
This is to prevent cracking.

As described above, the total depth of the two main surfaces of the secondary division groove 2 can be made shallower than the total depth of the two main surfaces of the primary division groove 1, and the depth of the front and back surfaces of the secondary division groove 2 can be further reduced. By reversing the above, it is possible to prevent the occurrence of a bar break defect in which the secondary division groove 2 is broken when the primary division groove 1 is divided by the roller method or the bending method described above.

[0010]

However, in recent years, chip electronic components have been further reduced in thickness and size, and this tendency is the same in chip resistors 11, and ceramic electronic components can be accurately and reliably formed using a conventional dividing device. It has become difficult to divide the substrate 12.

In the aforementioned Japanese Patent No. 2889293 and Japanese Patent Publication No. 5-5421, the depth of the primary dividing groove 1 is formed to be about 50% of the thickness T of the substrate, The total depth of the surfaces was formed to be shallower than the total depth of both main surfaces of the primary division groove 1 in order to prevent bar breakage defects occurring at the time of division of the primary division groove 1.

However, when the thickness T of the ceramic substrate 12 is 2
In the case of a thin substrate having a thickness of 30 μm or less, if the total depth of both main surfaces of the division groove 6 exceeds about 40% of the thickness T of the ceramic substrate 12, the step of forming the division groove 6 of the ceramic substrate 12, the firing step, and the subsequent chip There is a problem that the dividing groove 6 is cracked in the printing process and the firing process of the resistor 11 and a problem that the secondary dividing groove 2 is broken at the time of dividing the primary dividing groove 1 is frequently broken.

On the other hand, JP-A-3-64089 discloses that
Further, the depth of the printing surface of the secondary division groove 2 is formed shallower than the back side thereof, and the secondary division groove 2 is divided when the primary division groove 1 is divided.
Although the consideration is given to the broken bar which is broken, the depth range of the dividing groove 6 described is remarkably wide, and the minimum value is adopted even when the thickness T of the ceramic substrate 12 is adopted for a thin plate having a thickness T of 230 μm or less. The problem that the dividing groove 6 is broken in the step of forming and firing the dividing groove 6 of the ceramic substrate 12 and the subsequent step of printing and firing the chip resistor 11, and the problem that the secondary dividing groove 2 There has been a problem that cracking failure of the bar is frequently caused.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of these circumstances, and has a lattice-shaped dividing groove arranged corresponding to both main surfaces, and is arranged on the short side of a rectangular lattice-shaped area. The total depth of both main surfaces of the formed primary division groove is shallower than the total depth of both main surfaces of the secondary division groove formed on the long side of the region in the lattice, and the primary division groove has a resistance. The formation surface is deeper than the back surface,
When the back surface of the secondary dividing groove is deeper than the resistance forming surface, the thickness of the ceramic substrate is 200 ± 30 μm, and the area in the lattice is 600 μm × 300 μm or less, the depth of the resistance forming surface of the primary dividing groove is 20 ± 10 μm. The depth of the back surface is 10 ± 5 μm, and the depth of the resistance forming surface of the secondary division groove is 1
0 ± 5 μm, the depth of the back surface is 40 ± 10 μm, and the opening angle of the resistance forming surface of the primary dividing groove and the dividing groove on the back surface of the secondary dividing groove is 30 ± 10 °, the back surface of the primary dividing groove and The opening angle of the dividing groove on the resistance forming surface of the secondary dividing groove is set to 40 ± 5 °.

[0015]

Embodiments of the present invention will be described below.

A ceramic substrate 1 for a chip resistor according to the present invention.
2 is, for example, an Al ₂ O ₃ content of 93.0 to 99.6% by weight.
The slurry obtained by mixing the alumina powder of Example 1 with a sintering aid, a solvent and a resin binder is formed into a ceramic green sheet 5 by a doctor blade method, and a blade 8 provided in a mold is fixed to the green sheet 5 by a predetermined amount. To form a dividing groove 6 by pressing to a depth of 2 mm, and then firing at a predetermined temperature. The ceramic material may be aluminum nitride, mullite, forsterite, glass ceramic, or the like, in addition to alumina.

As shown in FIG. 1, the dividing grooves 6 are arranged in a large number of lattices corresponding to both main surfaces, and the primary dividing grooves 1 are arranged on the short side 3a of the in-grating area 3. The secondary division groove 2 is formed on the long side 3 b of the inner region 3.

In the manufacturing process of the chip resistor 11, the resistor 13 is formed only on one main surface of the ceramic substrate 12, as shown in FIG. In the present invention, the total depth of the resistance forming surface side primary division groove 1a and the back surface side primary division groove 1b is made larger than the total depth of the resistance formation surface side secondary division groove 2a and the back surface side secondary division groove 2b. The primary division groove 1 is formed to be deeper in the resistance forming surface than the rear surface, and the secondary division groove 2 is formed to be deeper in the rear surface than the resistance forming surface.

Further, in the ceramic substrate 12 having a thickness T of 200 ± 30 μm and a dimension of the in-grating region 3 of 600 μm × 300 μm or less, the depth of the resistance forming surface side primary dividing groove 1a is 20 ± 10 μm and the back side primary dividing groove. The depth of 1b is 10 ± 5 μm, and the depth of the secondary groove 2a on the resistance forming surface side is 1
0 ± 5 μm, the depth of the back side secondary division groove 2 b is 40 ± 10
μm, the opening angle θ of the dividing groove 6 is 30 ± 10 ° for the resistance forming surface side primary dividing groove 1a and the back side secondary dividing groove 2b, and the back side primary dividing groove 1b and the resistance forming surface side secondary dividing groove 2a. It is formed at 40 ± 5 °.

The reason why the primary division groove 1 is made shallower than the secondary division groove 2 is that the pitch P1 of the primary division groove 1 of the ceramic substrate 12 is equal to the pitch of the secondary division groove 2 as shown in FIG. As shown in FIG. 3 (b), the green sheet 5 expands and a tensile stress is exerted in the direction of the arrow from the center to the outside at the time of binder removal during firing of the green sheet 5 to reduce the secondary pitch. Although the stress on the dividing grooves 2 is dispersed, the stress concentrates on the primary dividing grooves 1 having a wide pitch, and cracks and cracks are likely to occur. This is for suppressing the occurrence of cracks and cracks. When the primary division groove 1 is formed shallowly, the dividing property when the primary division groove 1 is first divided is reduced. However, in the present invention, by using a division device described in detail later, the shallow primary division groove 1 is formed. Even if there is, it can be divided well.

The thickness T of the ceramic substrate 12 is 230
In the case of μm or less, the primary dividing groove 1 and the secondary dividing groove 2
Is preferably 40% or less of the substrate thickness T. When the depth of the dividing groove 6 exceeds 40% of the thickness T,
The green sheet 5 is torn at the stage of forming the dividing groove 6 by pressing the blade 8 provided in the mold against the green sheet 5, and the subsequent firing step and the printing of the chip resistor 11 afterwards.
This is because the dividing groove 6 is broken in the firing step, and a bar breakage failure in which the secondary dividing groove 2 is broken in the dividing step of the primary dividing groove 1 is likely to occur. Therefore, the preferable range of the ratio of the thickness T of the primary divisional groove 1 and the secondary divisional groove 2 is 7.5 to 22.5% for the primary divisional groove 1 and 17.5% for the secondary divisional groove 2.
To 32.5%.

With respect to the depth of the resistance forming surface and the dividing groove 6 on the back surface, the surface for applying the pressing force at the time of dividing both the primary dividing groove 1 and the secondary dividing groove 2 is made deep. In order for the breaking direction to be perpendicular to the thickness direction of the substrate, it is sufficient that the breaking direction is deep enough to guide the breaking direction. Ceramic substrate 1 for chip resistor of the present invention
As will be described later, the pressing direction of the secondary division groove 2 is divided by applying a pressing force to the primary division groove 1 from the resistance forming surface side and then to the secondary division groove 2 from the back surface side.

The reason why the depth of the secondary division groove 2 is such that the resistance forming surface is shallow and the back surface is formed deep is that when the resistor 13 and the protective film 15 are printed on the ceramic substrate 12 and fired, as shown in FIG. The ceramic substrate 12 tends to warp into a valley shape due to the contraction force generated by the formation of the resistor 13 and the protective film 15. In this case, the ceramic substrate 12 is divided when the primary division groove 1 is divided.
When a pressure is applied, a load is applied to both ends of the valley-shaped substrate, and a bar breaking defect in which the secondary division groove 2 is broken easily occurs. This is to prevent this.

The opening angle θ between the resistance forming surface side primary dividing groove 1a and the back side secondary dividing groove 2b is determined by changing the back side primary dividing groove 1b.
The reason why the opening angle θ of the dividing groove 6 is small as shown in FIG. 5A is that the opening angle θ shown in FIG. The tearing stress on the green sheet 5 when forming the dividing grooves 6 is larger than that of the dividing grooves 6, and as a result, microcracks 7 are likely to be generated immediately below the dividing grooves 6, as shown in FIG. It is preferable that the microcracks 7 do not occur, but if they do occur, it is preferable that the microcracks 7 be located on the surface to be divided. If the microcracks 7 occur on the opposite side, it may cause bar breakage failure. Further, the reason why the division groove 6 having the narrow opening angle θ is made deep is to prevent the blade 8 provided in the mold from being pressed against the green sheet 5 to prevent the green sheet 5 from rising on the surface as shown in FIG. This is to reduce the volume of the blade 8 that penetrates deeply. On the other hand, the shallow dividing groove 6 is required to have a certain blade width in terms of the processing technology of the blade 8 of the mold and the strength of the blade 8 suitable for mass production molding of the ceramic substrate 12. Groove 6.

The ceramic substrate 1 for a chip resistor according to the present invention.
A method for manufacturing the chip resistor 11 using the second embodiment will be described. As in the manufacturing process of FIG. 11 described above, first, electrodes 14 are printed and fired on both main surfaces of the ceramic substrate 12, and then the primary division grooves 1 corresponding to the thickness direction of the ceramic substrate 12 are formed deeply. Printing the resistor 13 on the main surface
Bake. Next, after setting the resistance 13 to a predetermined resistance value by laser trimming, a protective film 15 is printed and fired on the resistance 13. Then, the primary division groove 1 formed shallower than the secondary division groove 2 is divided first, the electrodes 14 are printed and fired on the divided end faces, and then the secondary division groove 2 is divided.

The depth of the primary division groove 1 is extremely small, so that cracks can be prevented from occurring at the time of firing the green sheet 5 described above, and the primary division groove 1 has a depth at which good division can be performed by a division method described later. I have.

Next, the dividing method will be described. FIG. 7 (a)
The dividing principle of the dividing device is shown in the drawing. First, the lower sheet is formed so that the resistance forming surface of the ceramic substrate 12 is turned up and the dividing portion of the primary dividing groove 1 is located between the dividing portion 19 and the pressing portion 18 of the dividing device. The ceramic substrate 12 is placed on the substrate 20 and transported. Next, as shown in FIG.
Is driven by the drive shaft 22 which can rotate and move up and down.
Then, the pressing portion 18 is moved downward, and the stopper mechanism 24 regulates the downward movement of the pressing portion 18 so as to make contact with the ceramic substrate 12. As shown in FIG. 7 (c), when the drive shaft 22 further moves down, the split portion 19 is further moved down from the holding portion 18 by the seesaw mechanism of the connecting portion 23, and the substrate is pressed. Divide groove 1.

The primary division by this method is performed by the secondary division groove 2
The primary divisional groove 1 formed shallower than the total depth of the two main surfaces can be accurately divided, no additional pressing force is applied to the secondary divisional groove 2, and furthermore, the secondary divisional groove 2 receives a pressing force. Since the depth of the dividing groove 6 on the resistance forming surface is shallow, even if the ceramic substrate 12 has a valley shape, a bar break defect does not occur.

The secondary division may be performed by the above-described division method or a conventional roller method, in which the resistance-forming surface of the bar-shaped substrate 4 is turned downward, and a pressing force is applied from the back surface to perform division.

[0030]

EXAMPLE A ceramic green sheet 5 having an Al ₂ O ₃ content of 96.0% by weight was formed by a doctor blade method, and a blade 8 provided in a mold was pressed against the green sheet 5 to a predetermined depth to divide it. A groove 6 is formed and then baked at a predetermined temperature so that the outer dimension is 60.0 mm × 49.5.
mm, the thickness T is 200 μm, and the long side 3b in the lattice area 3
The dimension is 580 μm, and the dimension of the short side 3a of the in-grating region 3 is 2
A ceramic substrate 12 having a size of 90 μm and having 2880 in-grid regions 3 serving as chip resistors 11 was prepared for each of the chip resistor ceramic substrate 12 of the present invention and the conventional chip resistor ceramic substrate 12 of the comparative example. .

Ceramic substrate 1 for chip resistor of the present invention
As shown in Table 1, reference numeral 2 denotes a primary division groove 1a on the resistance forming surface side.
Of the sample A = 8 μm, sample B = 10 μm, sample C
= 20 μm, sample D = 30 μm, sample E = 32 μm, the depth of the back side primary division groove 1 b was 10 μm,
The depth of each of the resistance forming surface side secondary division grooves 2a is 10 μm.
m and the depth of the back side secondary division groove 2b were all 40 μm. Further, the opening angle θ of the dividing groove 6 of the resistance forming surface side primary dividing groove 1a and the back side secondary dividing groove 2b is 30 °, and the dividing groove 6 of the back side primary dividing groove 1b and the resistance forming surface side secondary dividing groove 2a. Was set to 40 °.

The ceramic substrate 12 of the comparative example also has the same shape, and the depth of the resistance forming surface side primary dividing groove 1a is 90 μm.
m, the depth of the resistance forming surface side secondary division groove 2a is 50 μm, the back side primary division groove 1b and the back side secondary division groove 2b
Was 10 μm. Also, the primary dividing groove 1
In addition, the opening angle θ of the dividing grooves 6 in both the secondary dividing grooves 2 was 30 ° on the resistance forming surface side and 40 ° on the back surface side.

The method of forming the dividing groove 6 is as follows. First, a mold provided with a blade 8 for forming the dividing groove 6 is pressed against both main surfaces of the green sheet 5 by a progressive press method. The primary division grooves 1 were simultaneously formed on both main surfaces in the same manner. Thereafter, firing was performed at a predetermined temperature to produce the ceramic substrates 12 of the examples of the present invention and the comparative examples.

The manufacturing method of the chip resistor 11 is the same as the manufacturing process of the chip resistor 11 shown in FIG. 11 described above. In the embodiment of the present invention, first, the electrodes 14 and the short The resistance 13 and the protective film 1 are provided on the deeper main surface of the divisional groove 6 corresponding to the thickness direction of the substrate of the primary divisional groove 1 formed on the side 3a.
5 was formed. Next, the primary dividing groove 1 to be divided
In addition, the pressing portion 18 and the split portion 19 of the splitting device shown in FIG.
The pressing force was applied at 2 to divide. After that, the electrode 14 was formed on the end face of the divided bar-shaped substrate 4, and the final secondary division was performed by applying a pressing force from the back side by the conventional roller method with the resistance forming side down.

The manufacturing process of the ceramic substrate 12 and the chip resistor 11 of the comparative example and the dividing device for the primary dividing groove 1 and the secondary dividing groove 2 are the same as those of the embodiment of the present invention, but the dividing direction is the primary dividing. Both the groove 1 and the secondary division groove 2 were divided by applying a pressing force from the resistance forming surface.

With respect to the examples of the present invention and the comparative example, the formation of the dividing groove 6 in the green sheet 5 and the formation of the chip resistor 11
The green sheet 5 is broken or the ceramic substrate 12 is not cracked until the secondary dividing groove 2 is divided, which is the manufacturing process of
Table 1 shows the occurrence rates of bar break failure and split burr failure. The size of the divided burrs is 15 μm.
The above was regarded as a burr defect.

Regarding the occurrence of the microcracks 7, the ceramic substrate 12 on which no printing or the like was applied was colored with oily red magic ink into the dividing grooves 6 by 5 sheets each in each of the examples and comparative examples of the present invention, and then divided. At any five points on each sheet, the divided cross section was observed with a tool microscope, the depth of the microcracks 7 in the substrate thickness direction was measured, and the average value was shown in Table 1.

[0038]

[Table 1]

From these results, in the comparative example, the total depth of both main surfaces of the primary division groove 1 was set to 50% of the substrate thickness T, and the total depth of both main surfaces of the secondary division groove 2 was set to the substrate thickness T. 30%, the resistance forming surface of each of the primary division groove 1 and the secondary division groove 2 is deeper than the back surface side, and the opening angle θ of the division groove 6 of the resistance formation surface.
Is reduced to 30 °, microcracks 7 having a depth of 18.5 μm are formed in the primary divisional groove 1a on the resistance forming surface side and 8.2 μm in the secondary divisional groove 2a on the resistance formation surface side, and green is formed. Breakage during the formation of the dividing groove 6 of the sheet 5, cracking during firing of the ceramic substrate 12, printing during the manufacturing process of the chip resistor 11, cracking during firing, and the secondary dividing groove 2 of the primary dividing groove 1 by the roller method. In addition, cracking failure of the bar, cracking failure of the divided burrs, and failure of the divided burrs of the secondary dividing groove 2 occurred frequently, and the total failure rate was as high as 52.7%.

On the other hand, the ceramic substrate 12 for a chip resistor of the present invention has a high total defective rate of 4.5 even if the total defective rate is high.
%, Which indicates that the yield can be increased.

Among the embodiments of the present invention, in the sample A in which the total depth of both the main surfaces with respect to the thickness T of the substrate of the primary division groove 1 is 9%, the split burr defect of the primary division groove 1 is 0.4%. high,
Further, in the sample E in which the total depth of both the main surfaces of the primary division groove 1 with respect to the thickness T of the substrate was 21%, the breakage when the division groove 6 was formed in the green sheet 5 was frequently 2.8%. Therefore, the preferable range of the total depth of both the main surfaces of the primary division groove 1 was Samples B, C, and D which were 10 to 20% of the thickness T of the substrate. The total depth of both main surfaces of the secondary dividing groove 2 was 25% of the thickness T of the substrate for the samples A to E, but there was no particular problem.

The reason why the defect rate of the embodiment of the present invention was significantly lower than that of the comparative example is that, in addition to the above-mentioned setting of the total depth of the division grooves 6, the resistance forming surface of the secondary division groove 2 was made shallow and its back surface was made By increasing the depth, even if the resistor 13 and the protective film 15 are formed and the ceramic substrate 12 warps into a valley shape, the occurrence of a bar break defect in which the secondary division groove 2 is broken at the time of primary division is suppressed. Further, the occurrence of microcracks 7 immediately below the dividing groove 6 is generally small because the depth of the dividing groove 6 is shallow, and in all the samples, the opening angle θ is as small as 30 ° and the primary dividing groove 1a on the resistance forming surface side is narrow. 3. In the back side secondary dividing groove 2b.
This is because micro-cracks 7 of about 0.7 μm or less were generated in the divided groove 6 having an opening angle θ of 7 μm or less and the opening angle θ on the opposite side being widened to 40 °, and did not affect the increase in the above-described respective defective rates. .

According to the above results, the thickness was 200 ± 30 μm
In the ceramic substrate 12 in which the size of the in-grating region 3 is not more than 600 μm × 300 μm, the depth of the resistance forming surface side primary division groove 1a of the ceramic substrate 12 is 20 ± 10 μm, and the depth of the back surface side primary division groove 1b is 10 ± 5 μm. The depth of the surface side secondary division groove 2a is 1
0 ± 5 μm, the depth of the back side secondary division groove 2 b is 40 ± 10
μm, the opening angle θ of the dividing groove 6 is 30 ° for the resistance forming surface side primary dividing groove 1a and the back side secondary dividing groove 2b, and 4 degrees for the back side primary dividing groove 1b and the resistance forming surface side secondary dividing groove 2a.
By setting 0 °, a thin and small chip resistor 11 is formed.
Can be manufactured with a highly efficient automatic machine line without lowering the yield.

[0044]

As described above, according to the ceramic substrate for a chip resistor of the present invention, the total depth of both main surfaces of the primary division groove is smaller than the total depth of both main surfaces of the secondary division groove, and the resistance forming surface is formed. Is formed deeper than the back surface, and a depth that can be satisfactorily divided by a dividing method described later. By the way, the resistance forming surface is formed shallower than the back surface, and the division of the primary division groove is performed by lowering the holding portion and the split portion of the substrate with the drive shaft via the connecting portion having the seesaw mechanism and pressing from the resistance forming surface. The secondary division groove is divided by the above-mentioned method or the conventional roller method by pressing from the back surface of the resistance forming surface to have a thickness of 2%.
Even in the case of a ceramic substrate having a size of 30 μm and a lattice area of 600 × 300 μm or less, the occurrence of cracks in the ceramic substrate manufacturing process and chip resistor manufacturing process, bar breakage when dividing the primary division groove, and division burr defect is suppressed. ,Also,
It can be manufactured with a highly efficient automatic machine line.

[Brief description of the drawings]

FIG. 1 is a perspective view of a ceramic substrate for a chip resistor according to the present invention.

FIG. 2 is a perspective view of a ceramic substrate for a chip resistor of the present invention on which a resistor is formed.

FIG. 3A is a plan view of a ceramic substrate for a chip resistor, and FIG. 3B is a plan view of a green sheet showing a tensile stress during firing.

FIG. 4 is a cross-sectional view of the ceramic substrate after forming a resistor and a protective film.

FIGS. 5A and 5B are cross-sectional views of a green sheet showing the magnitude of a tearing stress, and FIG. 5C is a cross-sectional view of a green sheet showing the occurrence of microcracks.

FIG. 6 is a sectional view of a green sheet.

FIGS. 7A, 7B and 7C are cross-sectional views showing the principle of division of the device for dividing a ceramic substrate for a chip resistor according to the present invention.

FIG. 8 is a sectional view of a chip resistor.

FIG. 9 is a perspective view of a ceramic substrate for a chip resistor.

FIG. 10 is a cross-sectional view showing an example of forming a dividing groove in a green sheet by using a mold.

FIG. 11 is a manufacturing process diagram of the chip resistor.

FIGS. 12A and 12B are cross-sectional views illustrating an example of a dividing principle of a conventional dividing device.

13A and 13B are plan views showing examples of dividing a ceramic substrate for a chip resistor.

[Explanation of symbols]

1: primary division groove 1a: primary division groove 1 on the resistance forming surface side
b: back side primary division groove 2: secondary division groove 2a: resistance forming surface side secondary division groove 2
b: back side secondary division groove 3: area within lattice 3a: short side of area within lattice 3b: long side of area within lattice 4: bar-shaped substrate 5: green sheet 6: division groove
7: Micro crack 8, 8a, 8b: Blade 11: Chip resistor 12: Ceramic substrate 13: Resistance 14: Electrode 1
5: Protective film 16: Large-diameter roller 17: Small-diameter roller 18: Holding section 19: Split section 20: Lower sheet 21: Crank mechanism 22: Drive section
23: Connecting part 24: Stopper mechanism P1: Pitch of primary division groove P
2: Pitch of secondary division groove T: Thickness θ: Open angle

Claims (3)

[Claims] 1. A grid-shaped dividing groove is arranged corresponding to both main surfaces, and the total depth of both main surfaces of a primary dividing groove formed on the short side of a rectangular in-grating region is as described above. The shallower than the total depth of the two main surfaces of the secondary division groove formed on the long side of the region in the lattice, and the primary division groove has a resistance forming surface deeper than the back surface,
The ceramic substrate for a chip resistor, wherein the secondary division groove has a back surface deeper than a resistance forming surface. 2. The thickness of said ceramic substrate is 200 ± 30.
μm, the area in the lattice is 600 μm × 300 μm or less, and the depth of the resistance forming surface of the primary division groove is 20 ± 1.
0 μm, the depth of the back surface is 10 ± 5 μm, the depth of the resistance forming surface of the secondary division groove is 10 ± 5 μm, and the depth of the back surface is 40 ±
2. The ceramic substrate for a chip resistor according to claim 1, wherein the thickness is 10 [mu] m. 3. An opening angle between the resistance forming surface of the primary dividing groove and the back surface of the secondary dividing groove is 30 ± 10 °, and an opening angle of the back surface of the primary dividing groove and the resistance forming surface of the secondary dividing groove is 30 °. 3. The ceramic substrate for a chip resistor according to claim 2, wherein the angle is 40 ± 5 °.