JP3935030B2 - Electronic component mounting substrate and electronic component mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component mounting board having a multilayer capacitor portion therein.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an electronic component mounting board having a multilayer capacitor portion therein includes, as shown in FIGS. 5 to 7, a mounting region 43 for mounting an electronic component 42 such as an IC or LSI on the upper surface of an insulating substrate, an electronic component A mounting portion 46 composed of electrodes for connecting 42 with solder 44 and the like, a base 41 on which a wiring conductor 45 drawn from the mounting portion 46 is formed, and a multilayer capacitor portion 47 formed inside the base 41 It is mainly composed.
[0003]
The multilayer capacitor unit 47 is formed by laminating an inner layer power source conductor layer and an inner layer conductor layer 49 as an inner layer ground conductor layer through an insulating layer 48, and a plurality of through conductors penetrating the multilayer capacitor unit 47 are formed. Has been.
[0004]
Of the plurality of through conductors, the first through conductor 50 a has one end connected to the wiring conductor 45 and the other end connected to the electrode pad 51. The second through conductor 50b electrically connects the inner power supply conductor layer and the inner ground conductor layer of the multilayer capacitor unit 47. The penetrating conductor is provided with a land 52 formed by a conductor non-forming portion 53 concentrically surrounding a portion penetrating the inner power supply conductor layer or the inner ground conductor layer.
[0005]
FIG. 6 shows a land 52 provided in the second through conductor 50b.
[0006]
The land 52 is for preventing a conduction failure due to a laminating deviation of the through conductor when the multilayer capacitor portion 47 is formed. As shown in FIG. 7, the land 52 is formed in an annular shape around the through conductor, and is connected to and integrated with the through conductor. Around the land 52, a conductor non-forming portion 53 surrounding the through conductor concentrically is formed, and the periphery is surrounded by an inner conductor layer 49.
[0007]
The lands 52 have the same diameter, and the width X of the conductor non-forming portion 53 provided around each land 52 is also the same.
[0008]
In such an electronic component mounting board 41, an electrical capacitance component is generated between the inner conductor layers 49 facing each other through the insulating layer 48 in the multilayer capacitor unit 47. When each electrode of the electronic component 42 and the wiring conductor 45 are connected so that the capacitance component generated in the multilayer capacitor unit 47 is connected between the power supply electrode and the ground electrode of the electronic component 42, the electronic component 42 is connected to the power supply voltage. It is possible to protect against power supply noise caused by fluctuations. That is, the multilayer capacitor unit 47 functions as a decoupling capacitor.
[0009]
In recent years, the power consumption of the electronic component 42 has increased as the performance has increased. For this reason, it is desired to increase the capacity of the multilayer capacitor unit 47 with respect to the electronic component mounting board 41 as described above. As a configuration for increasing the capacity of the multilayer capacitor unit 47, a configuration in which the insulating layer 48 is thinned to be multilayered can be considered.
[0010]
[Problems to be solved by the invention]
However, in the above-described conventional electronic component mounting substrate 41, in order to increase the capacity of the multilayer capacitor portion 47, if the insulating layer 48 is made thinner, it is necessary to make the ceramic green sheet for forming the insulating layer 48 thinner. Therefore, the ceramic green sheet is difficult to be plastically deformed. As a result, when the ceramic green sheets are laminated and pressure-bonded, the conductive paste layer that becomes each conductor layer printed on the ceramic green sheets is not easily embedded in the ceramic green sheets. Then, a step is generated between the conductive paste layer and the portion where it does not exist in the ceramic green sheet. For example, in the portion of the conductor non-forming portion 53 around the land 52 of the penetrating conductor, sufficient pressure necessary for adhesion cannot be applied, and the ceramic green sheets are difficult to adhere to each other, and the ceramic green sheet laminate is fired. There is a problem in that a gap is easily formed between the insulating layers 48 in the body.
[0011]
The multilayer capacitor portion 47 in which such a gap is formed has insufficient mechanical strength around the through conductor, and is liable to cause insulation failure due to current leakage. Further, when the exposed wiring conductor 45 is plated, the processing liquid may enter the gap. The plating solution that has entered the gap corrodes the lands 52 and the inner conductor layer 49 and causes a decrease in insulation between them.
[0012]
In addition, when the multilayer capacitor portion 47 is made multilayer, it becomes difficult to obtain sufficient bonding strength between the insulating layers 48 due to the gaps between the insulating layers 48, and therefore, it is easy to separate between the insulating layer 48 and the inner conductor layer 49. There was also the problem of becoming.
[0013]
Accordingly, the present invention has been completed in view of the above-described conventional problems, and an object of the present invention is to increase the mechanical strength around the through conductor in the electronic component mounting board having the multilayer capacitor portion 7 therein. Another object of the present invention is to provide an electronic component mounting board capable of ensuring insulation between a land of a multilayer capacitor portion and a conductor layer.
[0014]
[Means for Solving the Problems]
In the electronic component mounting substrate of the present invention, a mounting portion composed of an electrode for mounting the electronic component and a wiring conductor drawn from the electrode are formed on the upper surface of the insulating substrate formed by laminating a plurality of insulating layers. In addition, a base having electrode pads formed on the lower surface of the insulating substrate, and an inner power source conductor layer and an inner ground conductor layer formed in the base are alternately laminated so as to face each other with the insulating layer interposed therebetween. A multilayer capacitor portion, a first through conductor formed through the multilayer capacitor portion and extending from the wiring conductor to the electrode pad, and the inner power supply conductor layers of the multilayer capacitor portion or the inner ground conductor layer. A second through conductor that electrically connects each other, and the first and second through conductors penetrate the inner power supply conductor layer or the inner ground conductor layer. Or a land connected to them by a conductor non-forming portion that concentrically surrounds the portion, and a land made of a conductor layer independent of the inner power supply conductor layer or the inner ground conductor layer is provided and adjacent to the land. An auxiliary conductor layer facing the land and the conductor non-forming portion is provided at a portion passing through or connected to the inner ground conductor layer or the inner power supply conductor layer.
[0015]
[Means for Solving the Problems]
In the electronic component mounting substrate of the present invention, a mounting portion composed of an electrode for mounting the electronic component and a wiring conductor drawn from the electrode are formed on the upper surface of the insulating substrate formed by laminating a plurality of insulating layers. In addition, a base body in which electrode pads are formed on the lower surface of the insulating substrate, and a multilayer capacitor section in which inner conductor layers formed inside the base body are alternately stacked so as to face each other through the insulating layer; A first through conductor formed through the multilayer capacitor portion and extending from the wiring conductor to the electrode pad, and a second through conductor electrically connecting the inner layer conductor layers of the multilayer capacitor portion. The first and second penetrating conductors are provided in a portion penetrating the inner layer conductor layer at a portion that penetrates the inner layer conductor layer, and is independent of the inner conductor layer by a conductor non-forming portion that concentrically surrounds the portion. A land formed of layers, and in the stacking direction of the insulating layer, the land and the conductor are not formed at a portion that penetrates or is connected to the inner conductor layer adjacent to the conductor non-forming portion. An auxiliary conductor layer facing the part is provided in an annular shape spaced apart from the first and second through conductors.
The electronic component mounting structure according to the present invention mounts an electronic component on the electronic component mounting substrate according to the present invention, and electrically connects a power electrode and a ground electrode of the electronic component to the inner conductor layer of the multilayer capacitor portion. It is characterized by being connected to.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The electronic component mounting board of the present invention will be described in detail below. 1 and 2 are a sectional view and an enlarged sectional view showing an example of an embodiment of the present invention. In these drawings, 1 is a base, 2 is an electronic component, 3 is a mounting portion, 4 is solder, 5 is a wiring conductor, and 6 is a mounting area.
[0017]
In the electronic component mounting substrate of the present invention, a mounting portion 3 composed of an electrode for mounting the electronic component 2 and a wiring conductor 5 drawn from the electrode are formed on the upper surface of the insulating substrate formed by laminating a plurality of insulating layers. And the base 1 in which the electrode pad 11 is formed on the lower surface of the insulating substrate and the inner power source conductor layer and the inner ground conductor layer formed in the base 1 are alternately arranged so as to face each other with the insulating layer 8 therebetween. A multilayer capacitor portion 7 that is laminated to each other, a first through conductor 10 that is formed from the wiring conductor 5 to the electrode pad 11 through the multilayer capacitor portion 7, and inner power supply conductor layers or inner layers of the multilayer capacitor portion 7. A second through conductor 10b that electrically connects the ground conductor layers to each other, and the first and second through conductors 10a and 10b pass through or through the inner power supply conductor layer or the inner ground conductor layer. A land 12 consisting of a conductor layer independent of the inner power supply conductor layer or the inner ground conductor layer is provided in the subsequent part by the conductor non-forming portion 13 concentrically surrounding the part, and the adjacent inner ground conductor layer or The auxiliary conductor layer 14 that opposes the land 12 and the conductor non-forming portion 13 is provided in a portion that passes through or is connected to the inner power supply conductor layer.
[0018]
The substrate 1 of the present invention includes an aluminum oxide sintered body (aluminum oxide ceramics), an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, a silicon nitride sintered body, a glass ceramic, and the like. It consists of an insulating substrate on which a substantially square plate-like insulating layer made of an electrically insulating material is laminated.
[0019]
When the substrate 1 is made of an aluminum oxide sintered body, it is manufactured as follows. Appropriate organic binder, solvent, plasticizer and dispersant are added to and mixed with ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. to form a slurry, and this is formed into a sheet by a conventionally known doctor blade method. By molding into a plurality of ceramic green sheets. Next, a ceramic green sheet molded body to be the substrate 1 is obtained by subjecting these ceramic green sheets to appropriate punching, laminating, and cutting. Thereafter, the ceramic green sheet compact is produced by firing at a temperature of about 1600 ° C.
[0020]
The base body 1 is provided with a large number of wiring conductors 5 on its upper surface, one end of which is a mounting portion 3 made of an electrode, and the other end is connected to a first through conductor 10a penetrating the multilayer capacitor portion 7. Has been. The wiring conductor 5 is made of a metallized layer of a metal such as tungsten, molybdenum, copper, or silver, and is a metal paste obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, etc. to a metal powder such as tungsten. Is printed and applied in a predetermined pattern on a ceramic green sheet to be the base 1 by a well-known screen printing method, and this is fired together with a ceramic green sheet molded body to be the base 1 to thereby form a predetermined pattern on the upper surface of the base 1. Formed with. The wiring conductor 5 may also be formed inside or on the lower surface of the base body 1.
[0021]
The exposed surface of the wiring conductor 5 is nickel-plated with a thickness of about 1 to 10 μm in order to prevent the wiring conductor 5 from being oxidized and corroded and to improve the bonding between the wiring conductor 5 and the solder 4 and the like. A layer and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.
[0022]
In addition, a multilayer capacitor portion 7 in which inner layer conductor layers 9 as inner layer power supply conductor layers or inner layer ground conductor layers are alternately arranged via insulating layers 8 is formed inside the base body 1. The plurality of through conductors that penetrate the plurality of insulating layers 8 and the plurality of inner conductor layers 9 in the stacking direction are provided.
[0023]
The inner conductor layer 9 is made of the same material as that of the wiring conductor 5 and has a thickness of 1 to 5 μm. The insulating layer 8 has a thickness of about 20 to 30 μm when the substrate 1 is made of, for example, an aluminum oxide sintered body. Thus, the capacity of the multilayer capacitor portion 7 is increased by thinning the insulating layer 8 and alternately arranging the inner conductor layers 9 via the insulating layers 8. Then, each electrode of the electronic component 2 and each inner conductor layer 9 corresponding to each electrode are connected so that the capacitance component generated in the multilayer capacitor unit 7 is connected between the power electrode and the ground electrode of the electronic component 2. When the wiring conductors 5 are connected, the electronic component 2 can be protected from power supply noise caused by fluctuations in the power supply voltage. That is, the multilayer capacitor unit 7 functions as a decoupling capacitor.
[0024]
Further, the first through conductor 10a penetrates the multilayer capacitor portion 7, the upper end is electrically connected to the wiring conductor 5, and the lower end is connected to the electrode pad 11 for external connection formed on the lower surface of the substrate 1. Has been. There are two first through conductors 10a, which are connected to the inner conductor layers 9 corresponding to the input part and the output part of the capacitive component generated in the multilayer capacitor part 7, respectively. The second through conductors 10b are for electrically connecting the inner power supply conductor layers or the inner ground conductor layers of the multilayer capacitor unit 7 to reinforce their potential, and two or more second through conductors 10b can be provided.
[0025]
These through conductors are cylindrical, and are formed by forming through holes in each ceramic green sheet by punching and filling the through holes with a conductive paste. This conductive paste is made of a refractory metal similar to the wiring conductor 5 and the inner conductor layer 9.
[0026]
Further, as shown in FIG. 2, the through conductor has a land 12 made of a conductor layer independent from the inner layer conductor layer 9 extending in the same plane as the inner layer conductor layer 9 at a portion passing through or connecting to the inner layer conductor layer 9. is doing. As shown in FIG. 7, the land 12 has an annular shape formed coaxially with the through conductor, and is made of the same high melting point metal as the wiring conductor 5 and the inner conductor layer 9. A conductor non-formed portion 13 having a width X (about 0.01 to 0.5 mm) is formed around the land 12, and the periphery is surrounded by the inner conductor layer 9. The land 12 is integrally connected to the through conductor.
[0027]
Furthermore, the electrode pad 11 formed on the lower surface of the substrate 1 to which the first through conductor 10a is connected has a plated layer with good corrosion resistance and conductivity such as nickel and gold on the surface thereof. This plating layer is for preventing the electrode pad 11 from being corroded and increasing the connection strength between the electrode pad 11 and the electrode of the external electric circuit board. The thickness of the plating layer is about 1 to 20 μm. is there.
[0028]
The electronic component substrate of the present invention includes a land 12 and a conductor non-forming portion at a portion where the through conductor passes through or is connected to the inner conductor layer 9 adjacent to the inner conductor layer 9 on which the land 12 is formed. An auxiliary conductor layer 14 facing 13 is provided. As a result, when the ceramic green sheets to be the insulating layer 8 are laminated and pressure-bonded, the portion where the auxiliary conductor layer 14 is formed locally increases the pressure-bonding force of the ceramic green sheet. It is possible to fill a step formed in the portion of the conductor non-forming portion 13 around the land 12 to be formed. As a result, the adhesion between the ceramic green sheets is improved, and the formation of a gap between the insulating layers 8 in the fired body of the ceramic green sheet laminate can be effectively prevented. Therefore, the mechanical strength around the through conductor can be increased, and insulation between the land 12 of the multilayer capacitor portion 7 and the inner conductor layer 9 can be secured.
[0029]
The auxiliary conductor layer 14 is substantially circular, and its diameter is preferably about 0.01 to 0.5 mm larger than the combined diameter of the land 12 and the conductor non-forming portion 13. In this case, even if a stacking deviation occurs between the ceramic green sheets, the step of the conductor non-forming portion 13 is filled with the thickness of the auxiliary conductor layer 14, so that the pressure necessary for adhesion can be applied and good adhesion is achieved. Can be granted. In this case, if the thickness is less than 0.01 mm, the step of the conductor non-forming portion 13 cannot be filled by the thickness of the auxiliary conductor layer 14 due to the laminating deviation of the ceramic green sheet, and the adhesiveness is lowered without applying the pressure necessary for adhesion. Tend to. On the other hand, if the thickness exceeds 0.5 mm, the overlapping portion of the inner conductor layer 9 other than the conductor non-forming portion 13 and the auxiliary conductor layer 14 becomes large, and if a pressure for adhesion is applied, the ceramic green sheet is deformed, and the ceramic There is a tendency that a gap is generated between the green sheets and the adhesion is lowered.
[0030]
The thickness of the auxiliary conductor layer 14 is preferably 2 to 15 μm. If it is less than 2 μm, it becomes difficult to fill the step of the conductor non-forming portion 13 with the thickness of the auxiliary conductor layer 14 and apply the pressure necessary for adhesion. When the thickness exceeds 15 μm, a sufficient pressure for adhesion can be obtained, but a step is easily formed around the auxiliary conductor layer 14.
[0031]
3 and 4 are a cross-sectional view and an enlarged cross-sectional view of the main part showing another example of the embodiment of the present invention. The electronic component having the structure shown in FIGS. This is the same as the mounting substrate. In this case, at least one of the inner conductor layers 9 adjacent to each other in the laminating direction across the land 32 and the insulating layer 8 is preferably 0.01 to 0.5 mm more than the width of the conductor non-forming portion 13 around the central axis of the through conductor. An annular auxiliary conductor layer 34 having a large width is formed so as to face the conductor non-forming portion 13. For this reason, when the ceramic green sheets are laminated and pressure-bonded, the thickness of the auxiliary conductor layer 34 formed on the surface of the inner conductor layer 9 is generated in the portion of the conductor non-forming portion 13 around the land 12 of the through conductor. The pressure required for adhesion can be applied so that the level difference can be filled. As a result, the adhesion between the ceramic green sheets can be improved, and the formation of a gap between the insulating layers 8 can be effectively prevented in the fired body of the ceramic green sheet laminate.
[0032]
Note that the width of the auxiliary conductor layer 34 is preferably 0.01 to 0.5 mm larger than the width of the conductor non-forming portion 13. In this case, even if a stacking error occurs between the ceramic green sheets, good adhesion can be imparted. If the thickness is less than 0.01 mm, the adhesion tends to decrease due to misalignment. On the other hand, if the thickness exceeds 0.5 mm, the overlapping portion of the inner conductor layer 9 and the auxiliary conductor layer 34 around the conductor non-forming portion 13 increases. When the pressure for adhesion is applied, the ceramic green sheet is deformed, and a gap is generated between the ceramic green sheets, and the adhesion tends to be lowered.
[0033]
Thus, according to the electronic component mounting substrate of the present invention, the electronic component 2 is fixed to the mounting portion 6 via the solder 4, and each electrode of the electronic component 2 and the electrode of the wiring conductor 5 are connected by the solder 4. . As a result, the power supply electrode and the ground electrode of the electronic component 2 are connected to the wiring conductor 5 connected to the inner conductor layer 9. Then, after the electronic component 2 is covered and sealed with, for example, a resin, the electrode pad 11 is fixed to an electrode or the like on the external electric circuit board with a conductive bonding material such as solder.
[0034]
Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.
[0035]
【The invention's effect】
In the electronic component mounting board of the present invention, a mounting portion composed of an electrode for mounting the electronic component and a wiring conductor drawn from the electrode are formed on the upper surface of the insulating substrate formed by laminating a plurality of insulating layers. A multilayer capacitor in which a base body having electrode pads formed on the lower surface of an insulating substrate, and an inner power source conductor layer and an inner ground conductor layer formed inside the base body are alternately stacked so as to face each other with an insulating layer therebetween A first through conductor formed between the wiring conductor and the electrode pad through the multilayer capacitor portion, and a second power source electrically connecting the inner power supply conductor layers or the inner ground conductor layers of the multilayer capacitor portion. The first and second through conductors are disposed concentrically at portions that penetrate or connect to the inner power supply conductor layer or inner ground conductor layer. A land made of a conductor layer independent of the inner power supply conductor layer or the inner ground conductor layer is provided by the surrounding conductor non-forming portion, and penetrates or is connected to the adjacent inner ground conductor layer or inner power conductor layer. Since the auxiliary conductor layer facing the land and the conductor non-forming portion is provided in the part, the part where the auxiliary conductor layer is formed is locally localized when the ceramic green sheet serving as the insulating layer is laminated and crimped. In particular, since the pressing force of the ceramic green sheet is increased, it is possible to fill a step generated in the portion of the conductor non-forming portion around the land facing the auxiliary conductor layer. As a result, the adhesion between the ceramic green sheets is improved, and the formation of a gap between the insulating layers in the fired body of the ceramic green sheet laminate can be effectively prevented. Therefore, the mechanical strength around the through conductor can be increased, and insulation between the land of the multilayer capacitor portion and the inner ground conductor layer or the inner power source conductor layer can be secured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic component mounting board according to the present invention.
2 is an enlarged cross-sectional view of a main part of the electronic component mounting board of FIG. 1;
FIG. 3 is a cross-sectional view showing another example of the embodiment of the electronic component mounting board of the present invention.
4 is an enlarged cross-sectional view of a main part of the electronic component mounting board of FIG. 3;
FIG. 5 is a cross-sectional view showing an example of a conventional electronic component mounting substrate.
6 is an enlarged cross-sectional view of a main part of the electronic component mounting board of FIG. 5;
FIG. 7 is a partial plan view showing a land portion provided on a through conductor of an electronic component mounting board.
[Explanation of symbols]
1: Substrate 2: Electronic component 3: Mounting portion 4: Solder 5: Wiring conductor 7: Multilayer capacitor portion 8: Insulating layer 9: Inner layer conductor layer
10a: First through conductor
10b: Second through conductor
11: Electrode pad
12: Land
13: Conductor non-forming part
14: Auxiliary conductor layer

Claims (2)

A mounting portion composed of an electrode for mounting an electronic component and a wiring conductor drawn from the electrode are formed on an upper surface of an insulating substrate formed by laminating a plurality of insulating layers, and an electrode pad is formed on the lower surface of the insulating substrate. A multilayer capacitor part formed by alternately laminating the formed base, the inner conductor layer formed inside the base so as to face each other with the insulating layer interposed therebetween, and the multilayer capacitor part penetrating the multilayer capacitor part A first through conductor formed from the wiring conductor to the electrode pad, and a second through conductor that electrically connects the inner conductor layers of the multilayer capacitor portion, the first and first second through conductor, said inner conductor layer at a portion that penetrates and lands composed of a conductor layer that is independent of the inner conductor layer is provided by a nonconductive portion surrounding the said site concentrically Rutotomoni, wherein in the laminating direction of the insulating layer, the portion for connecting either or them through the inner conductor layer adjacent to the conductor-free portion, the auxiliary conductive layer facing the land and the conductor-free portion An electronic component mounting board characterized by being provided in an annular shape spaced apart from the first and second through conductors . 2. An electronic component comprising: an electronic component mounted on the electronic component mounting substrate according to claim 1; and a power electrode and a ground electrode of the electronic component electrically connected to the inner conductor layer of the multilayer capacitor portion. Mounting structure.

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