JP2004289187A - Manufacturing method of thick film multilayer substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a thick film multilayer substrate, by which the resistance of a thick film resistor can be simply made highly precise. <P>SOLUTION: In the manufacturing method of the thick film multilayer substrate, a thick film resistor 6 on a ceramic substrate 1 is burnt at a higher temperature than a glass insulating layer 2 which is burnt while contacting with the upper surface of thick film resistor 6. An experiment by the present inventors discloses that when the thick film resistor 6 is burnt at a higher temperature than the glass insulating layer contacting with the resistor 6, a resistance value fluctuation caused by a high temperature process of burning glass insulating layers 2 to 4 thereafter can be reduced. Probably, it is presumed that binding powers of ceramic particles and conductive particles configurating the thick film resistor 6 are enhanced and made compact by burning the thick film resistor 6 at a higher temperature, and thereby any solid phase diffusion becomes hard to occur between the thick film resistor 6 and the glass insulating layer 2 contacting with the thick film resistor 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a thick film multilayer substrate.

  Conventionally, when an insulating layer is printed and fired on a ceramic substrate, and a wiring pattern is printed and fired on the insulating layer to manufacture a thick-film multilayer substrate, a plurality of insulating layers and wiring patterns are all the same. Firing at a temperature. Therefore, by applying the above technology, printing and firing a thick film resistor on a ceramic substrate, and sequentially printing and firing a plurality of insulating layers on this ceramic substrate, a thick film resistor, a plurality of insulating layers and It is conceivable that all the wiring patterns are fired at the same temperature.

  However, in the above manufacturing method, since the firing temperature of the thick film resistor and the firing temperature of the insulating layer and the wiring pattern are the same, in the firing step after firing the thick film resistor, the thick film resistor and the thick film resistor come into contact with each other due to thermal influence. There is a problem that mutual diffusion and thermal stress occur between the insulating film and the insulating layer, and the resistance value of the thick film resistor fluctuates greatly. Therefore, as a conventional technique for addressing the above problem, at the following point, laser trimming is performed on the thick film resistor to adjust the resistance value.

  In the first prior art, laser trimming is performed before firing the all-glass insulating layer. In the second conventional technique, laser trimming is performed by passing through the all-glass insulating layer after firing the all-glass insulating layer. In the third conventional technique, laser trimming is performed through a window provided by opening an all-glass insulating layer. In the fourth prior art, laser trimming is performed through a window provided in the upper glass insulating layer and through the lowermost glass insulating layer.

  However, each of the above-described laser trimming methods has the following problems. First, in the first prior art, since the all-glass insulating layer and the wiring are baked after laser trimming, the resistance value of the thick-film resistance fluctuates due to their thermal influence. FIG. 6 shows an example of the resistance value variation of each of the three thick film resistors provided on the same substrate in each step. As is clear from the drawing, the absolute value of the resistance value variation differs depending on the sheet resistance value of the resistor or the shape of the resistor.

  In the second prior art, laser trimming is performed through a thick all-glass insulating layer, so that absorption, scattering, and reflection occur at each glass insulating layer and its interface, and the laser output is reduced for thick-film resistance trimming. Need to increase. However, there is a concern that the increase in the laser output may adversely affect peripheral wirings and circuit elements, such as thermal stress, due to an increase in thermal influence on the peripheral portion.

  In the third and fourth prior arts described above, wiring cannot be laid in the window, so when a large number of laser-trimmed thick-film resistors are required, the wiring pattern design becomes complicated, and the wiring length becomes longer than necessary. Since the film resistance is exposed, there is concern about the external environment resistance. The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a thick film multilayer substrate that can easily increase the resistance value of a thick film resistor.

  The method for manufacturing a thick-film multilayer substrate according to the present invention includes a thick-film resistor forming step of printing and firing a thick-film resistor on a ceramic substrate, and printing a first insulating layer on the thick-film resistor and the surface of the ceramic substrate. And baking the insulating layer forming step, wherein the thick film resistor is fired at a higher temperature than the first insulating layer in contact with the thick film resistor, and the thick film resistor is The sintering is performed at 820 to 1050 ° C., and the thick film resistor is baked at a temperature higher by 20 to 100 ° C. than that of the first insulating layer.

  When the temperature difference is less than 20 ° C., the fluctuation of the resistance value becomes large. When the temperature difference exceeds 100 ° C., the wiring conductor (usually Ag-based conductor (Ag, AgPd, AgPt) melts or solidifies with the wiring conductor). Problems such as phase diffusion occur.

  In a preferred aspect, the thick film resistor is fired at a higher temperature than a second insulating layer printed and fired after the first insulating layer. In a preferred aspect, the first insulating layer is formed after laser-trimming the thick film resistor. In a preferred aspect, the ratio between the resistance of the thick film resistor immediately after the laser trimming and the resistance of the thick film resistor at the end of the high-temperature step is stored, and the target resistance is corrected in advance based on the ratio. Laser trimming is performed based on the obtained resistance value.

  The method of manufacturing a thick-film multilayer substrate according to the present invention includes a thick-film resistor forming step of printing and firing a thick-film resistor on a ceramic substrate, and printing an insulating layer on the surface of the thick-film resistor and the ceramic substrate. A method of manufacturing a thick-film multilayer substrate, comprising the step of forming an insulating layer by firing the glass film, wherein the glass contained in the thick-film resistor is crystallized glass by firing the thick-film resistor. In a preferred embodiment, the glass contained in the thick film resistor has a composition in which the melting point is increased by 50 ° C. or more in the crystallized state as compared with the amorphous state.

  The method of manufacturing a thick-film multilayer substrate according to the present invention includes a thick-film resistor forming step of printing and firing a thick-film resistor on a ceramic substrate, and printing an insulating layer on the surface of the thick-film resistor and the ceramic substrate. A method of manufacturing a thick-film multilayer substrate comprising: an insulating layer forming step of firing and firing. A glass contained in the insulating layer is converted into crystallized glass by firing the insulating layer. In a preferred aspect, the insulating layer is a first insulating layer in contact with the thick film resistor.

  In the method of manufacturing a thick film multilayer substrate according to the present invention, the thick film resistor on the ceramic substrate is fired at a higher temperature than the first insulating layer fired in contact therewith. By doing so, the following effects can be obtained.

  (1) A resistance value can be determined with high accuracy without using laser trimming in which a concave portion is formed in an insulating layer by a laser trimming mark or a window.

  That is, the change in the resistance value after the firing of the thick film resistor is caused by the subsequent high temperature process (firing the insulating layer, firing the wiring (circuit pattern and via-hole filled conductor)), especially the firing process of the insulating layer in contact with the thick film resistor. This is caused by mutual diffusion between the resistor and the insulating layer in contact with the resistor, thermal stress, and the like. However, according to experiments performed by the present inventors, it has been found that if the thick film resistor is fired at a higher temperature than the first insulating layer in contact with the thick film resistor, a change in resistance due to a high-temperature process such as subsequent firing of the insulating layer can be reduced. .

  Presumably, the high-temperature firing of the thick-film resistor enhances the reaction and bonding force between the glass particles and the conductive particles constituting the thick-film resistor. It is presumed that solid phase diffusion hardly occurs between the first insulating layer and the first insulating layer in contact therewith.

  (2) By performing laser trimming after firing the thick film resistor and before forming the first insulating layer, it is possible to obtain a higher-precision resistance value. Further, since the thick film resistor can be covered with the insulating layer, the stability is excellent and the wiring can be performed.

  That is, since the thick film resistor is fired at a high temperature and is stable, even if the insulating layer is fired after the laser trimming, the variation in the resistance value is small. Therefore, there is no need to provide a window or the like in the insulating layer, and it is not necessary to increase the laser output for transmission through the insulating layer.

  [First embodiment]

  One embodiment of the thick film multilayer substrate of the present invention will be described with reference to FIG. FIG. 1 shows a thick-film multilayer substrate having three glass insulating layers 2 to 4 on an alumina substrate 1.

  The wiring 5 and the thick film resistor 6 are printed and fired on the substrate 1, glass insulating layers 2 to 4 are formed thereon, and the wiring 7 and the protective glass 71 are formed on the glass insulating layer 4. I have. A circuit component 8 is soldered on the glass insulating layer 4. Reference numeral 9 denotes a hole filling conductor filled in the via hole. Hereinafter, a method of manufacturing the thick film multilayer substrate will be described.

  (Thick film resistance forming step) First, as shown in FIG. 2, Ag powder is kneaded with ethyl cellulose as a binder and terbineol as a solvent to prepare a conductor paste, and then alumina sintered at about 1600 ° C. The conductive paste is printed on the substrate 1 and fired in air at a firing profile of 800 to 1050 ° C. for 10 minutes to form the wiring 5.

  Next, after melting at 1200 to 1500 ° C., quenched in water and crushed, Ru02 powder is mixed with 50 to 80 vol% of glass powder having an average particle diameter of 2 to 5 μm and made of a mixture of PbO, Al 2 O 3, SiO 2, and B 2 O 3 having a predetermined mixing ratio. A mixed powder mixed at a predetermined vol% is prepared, and a solvent (for example, terbineol) and a binder (for example, ethyl cellulose) are added to the mixed powder and kneaded to prepare a resistor paste. Printing is performed so that the film thickness after firing is 7 to 15 μm, and firing is performed in air at a firing profile of 820 to 1050 ° C. for 10 minutes to form a thick film resistor 6.

  (Step of Forming Lowermost Layer of Glass Insulating Layer on Thick Film Resistor) Next, as shown in FIG. 3, after melting at 1200 to 1500 ° C., quenching in water, and pulverized CaO, Al 2 O 3 having a predetermined mixing ratio, A predetermined amount of a solvent (for example, terbineol) and a binder (for example, ethyl cellulose) are added to a glass powder having a mean particle size of 2 to 5 μm made of a mixture of ZrO, PbO, and the like, and kneaded to prepare a glass paste. This glass paste is printed on the alumina substrate 1 with a thickness of 15 to 25 μm, and is fired at a firing profile of 800 to 950 ° C. for 10 minutes to form the glass insulating layer 2.

  (Remaining Glass Insulating Layer and Internal Wiring Forming Step) Next, as shown in FIG. 4, a glass insulating layer 3 is formed in the same step as the above-described manufacturing step of the glass insulating layer 2, and then the conductive paste is applied. The via holes communicating with each other in the glass insulating layers 2 and 3 are screen-printed and filled, and fired in air at a firing profile of 800 to 950 ° C. for 10 minutes to form the lower portion of the hole-filled conductor 9.

  Next, the glass insulating layer 4 is formed in the same process as the manufacturing process of the glass insulating layer 2 described above, and then the Ag paste is screen-printed and filled into the via holes of the glass insulating layer 4 communicating with the via holes. The upper portion of the hole-filled conductor 9 is formed by sintering with a sintering profile maintained at 800 to 950 ° C. for 10 minutes.

  (Surface Layer Circuit Forming Step) Next, as shown in FIG. 4, a conductive paste is printed on the surface of the glass insulating layer 4 and baked at a firing profile of 800 to 950 ° C. for 10 minutes to form the wiring 7. The protective glass paste was printed thereon and fired in air with a firing profile having a peak temperature of 500 to 650 ° C. to form a protective glass layer 71.

  The protective glass paste is melted at 1200 to 1500 ° C., quenched in water, pulverized, and crushed into a glass powder having an average particle diameter of 2 to 5 μm composed of a mixture of PbO, SiO 2 and B 2 O 3 in a predetermined mixing ratio, a solvent (for example, terpineol) and a binder. (For example, ethylcellulose) was added in a predetermined amount and kneaded.

  (Circuit Component Mounting Step) Next, as shown in FIG. 1, the circuit component 8 was soldered to the surface of the fired substrate on the surface of the glass insulating layer 4 to complete the process.

  Further, a mixed powder of Ag and Pd or Ag and Pt may be used in the substrate forming process instead of the Ag powder of the conductor paste. Cu can be used, but in this case, firing must be performed in an N2 atmosphere to prevent oxidation. Further, in the surface layer circuit type process, after forming a wiring using a conductive paste, a resistor can be formed between the wirings.

Next, FIG. 5 shows the result of monitoring the change in the resistance value of the thick film resistor 6 at each end of each manufacturing process. In addition, a change in the resistance value of the thick film resistor prepared by the same method as that of the example is shown except that the firing of the thick film resistor 6 is performed at a firing profile of holding at 850 ° C. for 10 minutes. As can be seen from FIG. 6, the resistance value of the thick film resistor 6 is much smaller in the resistance value change of the product of the present example fired at a high temperature than the product of the comparative example.
[Second embodiment]

In the above embodiment, the laser trimming was not performed, but the laser trimming was performed after the formation of the thick film resistor 6 to accurately determine the value of the thick film resistor 6 to be a predetermined value. Glass insulating layers 2 to 4 may be formed on 1. Since the thick film resistor 6 is fired at a high temperature, even if the glass insulating layers 2 to 4 are fired at a low temperature on the thick film resistor 6, as shown in FIG.
[Third embodiment]

In the second embodiment, the laser trimming is performed before the glass insulating layers 2 to 4 are formed. However, the laser trimming may be performed after the glass insulating layer 2 is formed, and then the glass insulating layers 3 and 4 may be formed. By doing so, the resistance value fluctuation can be further reduced, and the thick film resistor 6 can be further covered with the glass insulating layers 3 and 4.
[Fourth embodiment]

  Another embodiment will be described.

  This embodiment is different from the first embodiment in that a large number of samples of the change rate Rr = R4 / R3 between the resistance value R3 of the thick film resistor 6 after the laser trimming and the resistance R4 of the thick film resistor 6 after the completion of the manufacturing process. Is calculated, and the resistance value R3 at the time of laser trimming is determined using the average change rate Rrm at the time of laser trimming.

  For example, the target resistance value of the thick film resistor 6 is Rx. Therefore, laser trimming is performed by laser trimming with the laser trimming set resistance value R3 of the thick film resistor 6 being R3 = Rx / Rrm. In this way, even when the glass insulating layer is baked after the laser trimming and the thermal history is applied to the thick film resistor 6, the change in the resistance value of the thick film resistor 6 due to the thermal history can be suppressed to the minimum. It becomes possible.

This is because the firing process of the glass insulating layer and the wiring after the laser trimming is constant, and the fluctuation of the resistance value due to the process is essentially within a certain range.
[Fifth embodiment]

  A modification of the fourth embodiment will be described below. In this embodiment, the average rate of change Rrm is stored in the memory of the computer which performs the resistance value comparison (comparison between the monitor resistance and the stored target resistance) in the laser trimming for all the thick film resistors 6 on the circuit board. Store them individually.

This is for compensating that the average change rate Rrm is slightly different depending on the position on the circuit board, the resistance value of each thick film resistor 6, and the like. In this way, even when the average change rate Rrm is slightly different depending on the position on the circuit board, the resistance value of each thick film resistor 6, and the like, the variation in the resistance value of each thick film resistor 6 due to the thermal history is minimized. be able to.
[Sixth embodiment]

  A modification of the fifth embodiment will be described below.

  A plurality of circuit boards (for example, four) are set as one lot and mounted on the same handling boat (for example, made of alumina) to perform each process. In this embodiment, in the memory of the computer that performs the resistance value comparison (comparison between the monitor resistance and the stored target resistance) in the laser trimming, the thick film resistors 6 that require laser trimming on each circuit board on the boat are stored. The average rate of change Rrm is individually stored for all the numbers. Then, laser trimming is individually performed on all the thick film resistors 6 requiring laser trimming, with each resistance value R3 as a target resistance Rx / Rrm.

  This is because the temperature or the like changes delicately for each circuit board depending on the mounting position of the circuit board on the ceramic boat. Therefore, even when the thick film resistor 6 formed at the same position on the circuit board has the delicate temperature change, This causes the resistance value to fluctuate. According to this embodiment, the resistance value fluctuation can be further suppressed.

  (Modification) Hereinafter, another modification will be described.

Modification 1
In the fourth embodiment, since the thickness of the thick film resistor 6 and the average rate of change Rrm after the thermal history have a fixed relationship, if a graph showing this relationship is stored, the thickness of the thick film resistor 6 can be reduced. The average change rate Rrm can be searched from this graph every time the change is made, and it is not necessary to experimentally derive the average change rate Rrm each time the thickness of the thick film resistor 6 is changed.

Modification 2
In this embodiment, after the thick film resistor 6 is formed and before the glass insulating layer 2 is formed, a barrier layer for preventing or reducing solid phase diffusion between the thick film resistor 6 and the glass insulating layer 2 is formed on at least the thick film resistor 6. Formed. This barrier layer may be formed before laser trimming, or may be formed thereafter. The condition of the barrier layer is that solid phase diffusion with the thick film resistor 6 is small, solid phase diffusion between the thick film resistor 6 and the glass insulating layer 2 is reduced, and the thermal history after the formation of the thick film resistor 6 is reduced. On the other hand, it is an insulating material that does not change phase, and for example, a silicon nitride film, an alumina film, or the like can be used. As a manufacturing process, a CVD method, a PVD method, a printing firing method, or the like can be used. When formed before laser trimming, it is necessary to have a thickness that can be melted by laser trimming.

Modification 3
In this embodiment, after the thick film resistor 6 is formed and before the glass insulating layer 2 is formed, or as the glass insulating layer 2, a buffer layer softer or more elastic than the immediately above glass insulating layer is formed on at least the thick film resistor 6. . This buffer layer may be formed before laser trimming or may be formed after laser trimming. The condition of the buffer layer is that solid-phase diffusion with the thick-film resistor 6 is small, solid-phase diffusion between the thick-film resistor 6 and the glass insulating layer 4 is reduced, and the thermal history after the formation of the thick-film resistor 6 is reduced. On the other hand, it is an insulating material that does not change phase, and a CVD method, a PVD method, a printing firing method, or the like can be adopted as a manufacturing process. When formed before laser trimming, it is necessary to have a thickness that can be melted by laser trimming.

  With this configuration, the thermal stress caused by the difference in the coefficient of thermal expansion between the thick film resistor 6 and the glass insulating layer 2 or 3 can be reduced by the buffer layer. Can be reduced.

Modification 4
In this embodiment, after the thick film resistor 6 is formed and before the glass insulating layer 2 is formed, or as the glass insulating layer 2, a thermal expansion intermediate between the coefficient of thermal expansion of the glass insulating layer immediately above and the coefficient of thermal expansion of the thick film resistor 6. A buffer layer having a modulus is provided. This buffer layer may be formed before laser trimming or may be formed after laser trimming. The condition of the buffer layer is that solid-phase diffusion with the thick-film resistor 6 is small, solid-phase diffusion between the thick-film resistor 6 and the glass insulating layer 4 is reduced, and the thermal history after the formation of the thick-film resistor 6 is reduced. On the other hand, it is an insulating material that does not change phase, and a CVD method, a PVD method, a printing firing method, or the like can be adopted as a manufacturing process. When formed before laser trimming, it is necessary to have a thickness that can be melted by laser trimming.

  With this configuration, the thermal stress caused by the difference in the coefficient of thermal expansion between the thick film resistor 6 and the glass insulating layer 2 or 3 can be reduced by the buffer layer. Can be reduced.

Modification 5
In this embodiment, the main component of the glass contained in the thick film resistor 6 is crystallized glass.

  In this way, the glass inside the thick film resistor 6 is crystallized when the thick film resistor 6 is fired, and the melting point of the crystallized glass increases. Preferably, a composition in which the melting point is increased by 50 ° C. or more in the crystallized state compared to the amorphous state is preferable. Therefore, the mutual reaction between the insulating layer and the thick film resistor 6 in the subsequent step of firing the insulating layer can be more effectively suppressed.

  Further, the same effect is obtained by using not only the glass inside the thick film resistor 6 but also the main component of the glass contained in the glass insulating layer 2 and the crystallized glass. That is, since the main component of the glass contained in the glass insulating layer 2 is crystallized glass, the interaction between the fired glass insulating layer 2 and the thick film resistor 6 adjacent thereto is suppressed. Thereby, the resistance value fluctuation of the thick film resistor 6 can be reduced.

FIG. 2 is a schematic cross-sectional view illustrating a thick-film multilayer substrate according to the first embodiment. FIG. 4 is a schematic cross-sectional view illustrating a manufacturing process of the first embodiment. FIG. 4 is a schematic cross-sectional view illustrating a manufacturing process of the first embodiment. FIG. 4 is a schematic cross-sectional view illustrating a manufacturing process of the first embodiment. FIG. 6 is a diagram illustrating a change in a resistance value of a thick film resistor after each step in Example 1. It is a figure which shows the fluctuation | variation of the resistance value after each process of three resistors formed in each part of the conventional thick film multilayer substrate.

Explanation of reference numerals

  1: substrate, 2-4: glass insulating layer, 6: thick film resistor

Claims (8)

A thick film resistor forming step of printing and firing a thick film resistor on a ceramic substrate; and an insulating layer forming step of printing and firing a first insulating layer on the surface of the thick film resistor and the ceramic substrate. In the method for manufacturing a film multilayer substrate,
The thick film resistor is fired at a higher temperature than the first insulating layer in contact with the thick film resistor, the thick film resistor is fired at 820 to 1050 ° C., and the thick film resistor is fired at the first insulating layer. Baking at a temperature higher by 20 to 100 ° C. than the above. 2. The method according to claim 1, wherein the thick film resistor is fired at a higher temperature than a second insulating layer printed and fired after the first insulating layer. 2. The method according to claim 1, wherein the first insulating layer is formed after the thick film resistor is laser-trimmed. A resistance value obtained by storing the ratio between the resistance value of the thick film resistor immediately after the laser trimming and the resistance value of the thick film resistor at the end of the high-temperature step, and correcting the target resistance value in advance based on the ratio. 2. The method according to claim 1, wherein laser trimming is performed based on the following. A thick film multilayer substrate comprising: a thick film resistor forming step of printing and firing a thick film resistor on a ceramic substrate; and an insulating layer forming step of printing and firing an insulating layer on the surface of the thick film resistor and the ceramic substrate. In the manufacturing method of
A method for manufacturing a thick-film multilayer substrate, wherein the glass contained in the thick-film resistor is crystallized glass by firing the thick-film resistor. 6. The method for manufacturing a thick-film multilayer substrate according to claim 5, wherein the composition of the glass contained in the thick-film resistance has a melting point higher by 50 ° C. or more than in the amorphous state. A thick film multilayer substrate comprising: a thick film resistor forming step of printing and firing a thick film resistor on a ceramic substrate; and an insulating layer forming step of printing and firing an insulating layer on the surface of the thick film resistor and the ceramic substrate. In the manufacturing method of
A method for manufacturing a thick-film multilayer substrate, wherein the glass contained in the insulating layer is crystallized glass by firing the insulating layer. 8. The method according to claim 7, wherein the insulating layer is a first insulating layer in contact with the thick film resistor.

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