JP2005251871A - Printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board wherein a resistance element having an accurate resistance value is incorporated in high mounting efficiency. <P>SOLUTION: The printed wiring board 10 is provided with an insulating layer 13, a first conductor pattern 22 formed on one side surface of the insulating layer 13, a second conductor pattern 23 formed on the other side surface thereof, and a resistance element 30<SB>j</SB>having at least one resistor 32<SB>jk</SB>that is embedded in the insulating layer 13 and of which one side edge is electrically connected with the conductor pattern 22 and the other side edge is electrically connected with the conductor pattern 23. Because of such the structure, when etching is conducted to form the conductor patterns 22 and 23, the resistor 32<SB>jk</SB>can be prevented from being eroded, and a printed wiring board can be realized wherein a resistance element having high accurate resistance value is built in. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printed wiring board, and more particularly to a printed wiring board with a built-in resistor.

  Conventionally, printed wiring boards incorporating resistance elements have been put into practical use. As a resistance element built in such a printed wiring board, there are one in which a resistor constituting the resistance element is formed by screen printing, one formed by etching, and one formed by a plating method.

  A resistance element having a resistor formed by screen printing is formed as follows, for example (see Patent Document 1). First, after laminating an insulator material layer and a conductor material layer, a desired conductor pattern is formed on the insulator material layer by a photoetching method. Subsequently, an undercoat layer is formed between predetermined conductor patterns formed on the insulator material layer. Then, a carbon paste is screen-printed on the undercoat layer and the end portion of the conductor pattern adjacent to the undercoat layer, and a resistor is provided. Thus, a resistance element built in the printed wiring board is formed (hereinafter referred to as “conventional example 1”).

In addition, as a method of forming a resistive element formed by screen printing, a resistive element is disposed on a copper foil by screen printing using an ink made of, for example, LaB ₆ , and then the resistive element is covered on the copper foil. A method of forming an insulating layer and etching the copper foil to form a desired conductor pattern is also known (hereinafter referred to as “conventional example 2”, see Non-Patent Document 1).

  Moreover, the resistance element which has the resistor formed by etching is formed as follows, for example (refer patent document 2). First, after laminating an insulating material layer, a resistive material layer, and a conductive material layer, a first photoresist corresponding to the shape of a desired resistor is formed on the conductive material layer, and etching is performed to select a conductive material layer. Perform removal. Subsequently, the resist material layer is selectively removed in the selectively removed region of the conductor material layer by etching with the first photoresist remaining. Next, after peeling off the first photoresist, a first photoresist corresponding to the shape of the desired conductor pattern is formed, and the conductor material layer is selectively removed by etching. Thus, a resistance element built in the printed wiring board is formed (hereinafter referred to as “conventional example 3”).

  Moreover, the resistance element which has the resistor formed by plating is formed as follows, for example (refer patent document 3). First, after laminating an insulator material layer and a conductor material layer, a desired conductor pattern is formed on the insulator material layer by a photoetching method. Subsequently, a resistor is formed by a plating method between predetermined conductor patterns formed in the insulator material layer. In forming the resistor, plating is performed on the insulating layer between the predetermined conductor patterns and on the end portion of the predetermined conductor pattern. Thus, a resistance element built in the printed wiring board is formed (hereinafter referred to as “conventional example 4”).

Japanese Patent Laid-Open No. 11-4056 JP-A-4-147695 US Pat. No. 6,281,090 DuPont, “DuPont Electronic Materials Built-in PCB” [online], 2002.2.15, [Search April 16, 2003], Internet <URL: http://www.dupont.co.jp/mcm/apri /print/ER.html>

  The techniques of Conventional Example 1 to Conventional Example 4 described above are all excellent from the viewpoint that a resistance element built in a printed wiring board can be easily formed. However, as in Conventional Example 1 or Conventional Example 2, a resistive element formed by screen printing technology (hereinafter, also referred to as “printing resistive element”) has a liquid paste flowing after printing, Due to the shrinkage, the thickness and width of the printed resistance element are likely to fluctuate, and the shape is likely to change due to bleeding. As a result, the resistance value cannot be controlled with high accuracy.

  Furthermore, the resistance value is likely to change due to the heat applied during the surface treatment or the heat or pressure applied when another layer is laminated via the prepreg on the top of the resistance element, and the variation tends to increase. Further, since the resin component remains in the resistance element in the technology of Conventional Example 1, various electronic components are mounted on the printed wiring board, and temperature drift is likely to occur due to heat generation during actual use, and a stable resistance value is obtained. Difficult to maintain.

In the technique of Conventional Example 2, LaB ₆ is sintered at a high temperature to form a resistance element. At this time, volume shrinkage occurs. For this reason, LaB ₆ can partially adhere to the surface of the copper foil, but does not sufficiently follow the surface of the copper foil. For example, the heat applied after forming the resistance element and the acid used during the formation The strength of the joint between LaB ₆ and the surface of the copper foil is likely to be lowered by a chemical solution such as alkali. Therefore, with the technique of Conventional Example 1 or Conventional Example 2, the resistance value of the resistance element cannot be accurately formed to a desired value. Further, the technique of Conventional Example 1 or Conventional Example 2 cannot maintain a stable resistance value.

  In Conventional Example 3, the conductor material layer is etched twice, and the resistance material layer is etched once, for a total of three times. In Conventional Example 3, since the resistor is formed on the insulating layer, the first side etching of the conductor material layer and the etching of the resistance material layer erode the side surfaces of the finally formed resistor. It was supposed to be. Therefore, in the technique of Conventional Example 3, it cannot be said that the resistance value of the built-in resistance element can be accurately formed to a desired value. In Conventional Example 3, in order to prevent erosion on the upper surface of the resistor, which is a factor that causes a greater accuracy degradation than the accuracy degradation due to side erosion, the resistor is eroded during the second etching of the conductor material layer. Do not use etchant.

  Moreover, in the prior art example 4, it was necessary to plate in the stepped region on the insulating layer and on the conductor pattern. For this reason, it is difficult to accurately control the resistance value of the resistance element.

  Further, in the conventional examples 1 to 4, since the resistor in the resistor element is formed in a plate shape extending in the direction along the surface of the insulator material layer, there is a limit to improving the mounting efficiency of the resistor element.

  The present invention has been made under the above circumstances, and a first object of the present invention is to provide a printed wiring board in which a resistive element having a highly accurate resistance value is incorporated with good mounting efficiency.

  The printed wiring board of the present invention includes: an insulating layer; a first conductor pattern formed on one surface of the insulating layer; a second conductor pattern formed on the other surface of the insulating layer; A resistive element embedded in a layer and having at least one resistor whose one end is electrically connected to the first conductor pattern and whose other end is electrically connected to the second conductor pattern And a printed wiring board.

  In this printed wiring board, a resistance element that constitutes a resistance element, a resistor for determining a resistance value is embedded in an insulating layer, and a terminal on one side thereof is electrically connected to a first conductor pattern formed on the surface on one side of the insulating layer. While being connected, the terminal on the other side is electrically connected to the second conductor pattern formed on the surface of the other side of the insulating layer. For this reason, even if a photoetching method or the like is used when forming the first conductor pattern or the second conductor pattern, the resistor is not eroded by etching.

  Further, the resistance element is constituted by a columnar resistor extending along the direction penetrating the insulating layer. For this reason, planar mounting density can be improved.

  Therefore, according to the printed wiring board of the present invention, it is possible to realize a printed wiring board in which a resistor having an accurate resistance value is incorporated with high mounting efficiency.

  In the printed wiring board of the present invention, the resistor element is electrically connected in at least one of a series and a parallel manner by the first pattern and the second pattern according to the resistance value thereof. It can be set as the structure which has these. In such a case, a plurality of resistors having the same shape are formed without forming the resistors having various shapes according to the resistance value, and the first pattern and the second pattern are used in at least one of the series and parallel modes. By electrically connecting, a resistance element having a desired resistance value can be obtained.

  The resistor of the present invention is mainly composed of at least one metal selected from the group consisting of nickel, cobalt, chromium, indium, lanthanum, lithium, tin, tantalum, platinum, iron, palladium, vanadium, titanium, and zirconium. Particularly preferred are nickel, chromium and iron. When these metals are used, it is possible to manufacture resistance elements having various resistance values and having little fluctuation in resistance value even at high temperatures.

  The resistor of the present invention includes a resistor formed by nickel-phosphorus plating containing 5 to 15% by weight of phosphorus with respect to the total weight of the plating. By containing phosphorus within this range, there is no pinhole in the resistor, corrosion resistance to chemicals such as heat, acid, alkali, etc., and resistance even when used in a high-temperature air atmosphere. It is possible to manufacture a resistance element that is less likely to change in value.

  As described above in detail, according to the printed wiring board of the present invention, there is an effect that it is possible to provide a printed wiring board in which a resistance element having an accurate resistance value is efficiently incorporated.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a cross-sectional view of a printed wiring board 10 according to an embodiment of the present invention. This printed wiring board 10 is a printed wiring board having three built-in resistance elements.

  As shown in FIG. 1, the printed wiring board 10 includes (a) an insulating layer 11 and (b) a conductor pattern 21 formed on the surface of the insulating layer 11 on the + Z direction side. In addition, the conductor pattern may be formed in the -Z direction side surface of the insulating layer 11, and it is not necessary to form it. Furthermore, an insulating layer and a conductor pattern may be sequentially stacked on the −Z direction side of the insulating layer 11.

The printed wiring board 10 includes (c) an insulating layer 12 formed on the surface of the insulating layer 11 and the conductor pattern 21 on the + Z direction side, and (d) an insulating layer 12 formed on the surface of the insulating layer 12 on the + Z direction side. Layer 13; (e) a conductor pattern 22 formed on the −Z direction side surface of insulating layer 13; (f) a conductor pattern 23 formed on the + Z direction side surface of insulating layer 13; and (g). And a resistance element 30 _j (j = 1 to 3). Here, the resistance element 30 _j is embedded in the insulating layer 13, the −Z direction side end is electrically connected to the conductor pattern 22, and the + Z direction side end is electrically connected to the conductor pattern 23. _Furthermore , at least one resistor 31 _jk (k = 1,...) _Is included. When the resistance element 30 _{j includes a} plurality of resistors 31 _jk (k = 1,...), A conductor pattern that electrically connects the end portions on the −Z direction side of the predetermined resistor 31. A resistive element 30 _j is composed of a part of the conductor pattern 23 that electrically connects part of 22 and / or ends in the + Z direction side and a plurality of resistors 31 _jk .

In FIG. 1, the resistor element 30 _j has three resistors 31 _jk (k = 1 to 3), and the resistors 31 _j1 , 31 _j1 , An example in which a resistor 31 _j2 and a resistor 31 _j3 are connected in series is shown. As a result, if each resistor 31 _jk has a resistance value of r [Omega] between the -Z direction side end and the + Z direction side end, the resistance value R _j of the resistance element 30 _j is 3r [ Ω].

Incidentally, as shown in FIG. 2 (A) the resistance element 30 _j shown in 'has three resistors 31 _jk (k = 1~3), by a portion of the part of the conductor pattern 22 and the conductive pattern 23 , if the resistor 31 _j1, the resistor 31 _j2 and the resistor 31 _j3 are connected in parallel, 'resistance R _j' of resistive element 30 _j becomes r / 3 [Ω]. Further, as in a resistance element 30 _j ″ shown in FIG. 2B, there are three resistors 31 _jk (k = 1 to 3), and a part of the conductor pattern 22 and part of the conductor pattern 23 , if what the resistor 31 _j1 and resistor 31 _j2 are connected in parallel is connected in series with resistor 31 _j3, the resistance element 30 _j "of the resistance R _j" is (3/2 ) R [Ω].

  The resistor and the coating on the surface thereof can be formed by a plating method, a CVD method, a PVD method, or the like, but it is particularly preferable to use a plating method capable of forming a dense and strong film. In the case of the plating method, either electrolytic plating or electroless plating can be employed. As the plating bath, a bath having a composition in which a plurality of the above-described various metals or alloys containing them are dissolved may be appropriately prepared and used.

  Among the plating methods, a method using a nickel plating bath (hereinafter referred to as “nickel plating”) can be most preferably used. In particular, it is preferable to add 5 to 15% by weight of phosphorus in the nickel plating bath with respect to the total weight of the metal and phosphorus. If the phosphorus content is less than 5% by weight, the resistance is likely to cause pinholes in the resistor, and the bond strength between the nickel crystals is small. This is because the corrosion resistance to chemicals such as alkalis tends to decrease. On the other hand, if the content exceeds 15% by weight, phosphorus in nickel is easily oxidized by oxygen, and the resistance value may change when used in a high-temperature air atmosphere.

In the above, three examples of the change in resistance value of the resistance element according to the formation mode of the conductor pattern 22 and / or the conductor pattern 23 when the resistance element has three resistors 31 _jk (k = 1 to 3) are shown. _{Depending on} the number of the bodies 31 _jk and the formation pattern of the conductor pattern 22 and / or the conductor pattern 23, resistance elements having various resistance values can be formed even if the resistance values of the resistors 31 _jk are all the same. .

  As the material for the insulating layers 11, 12, and 13, epoxy resin, glass cloth impregnated with epoxy resin, polyimide, and the like can be used because of excellent heat resistance and dimensional stability. The insulating layers 11, 12, and 13 may be formed using the same material, or may be formed using different materials.

  As a material of the conductor patterns 21, 22, and 23, a conductor metal such as copper, aluminum, and stainless steel can be used.

  Although not shown in FIG. 1, via holes, which are electrical conduction paths between layers, are appropriately formed in the insulating layers 11, 12, and 13, respectively. In addition, a pad for component mounting or motherboard mounting is formed on the conductor pattern 23 so that components can be mounted on the printed wiring board 10 or the printed wiring board 10 can be mounted on the motherboard. ing.

FIG. 3 schematically shows the configuration of the resistor module 40 used for manufacturing the printed wiring board 10. As shown in FIG. 3A, the resistor module 40 includes (a) a support member 41, (b) a conductor film 42U disposed on the + Z direction side surface of the support member 41, and (c ) A conductor film 42L disposed on the −Z direction side surface of the support member 41, and (d) resistance members 39 ₁ , 39 ₂ , and 39 ₃ formed on the + Z direction side surface of the conductor film 42U. Yes. Here, the support member 41 and the conductor film 42 are bonded with an adhesive so that they can be peeled later. As such an adhesive, benzotriazole or one containing a benzotriazole derivative, for example, trade name: VERZONE (Daiwa Kasei Co., Ltd., SF-310) can be used.

  Moreover, as the conductor films 42U and 42L, a copper film, a silver film, an aluminum film, etc. can be used. The thickness of such a conductor film is preferably 0.1 μm or more from the viewpoint of preventing the conductor film from disappearing in the etching step, and the conductor pattern obtained by etching the conductor film is made finer. From the viewpoint, it is preferably 20 μm or less. Moreover, when the thickness of the conductor film is 1 to 10 μm, the conductor film is not lost in the etching step, and a fine conductor pattern can be formed satisfactorily.

  The support member 41 includes: (i) a plate-like core member 44; (ii) a carrier member 43U disposed on the + Z direction side surface of the core member 44; and (iii) a −Z direction side surface of the core member 44. And a carrier member 43L disposed above. Here, as the material of the core member, an epoxy resin, a glass cloth impregnated with an epoxy resin, polyimide, or the like can be used in the same manner as the insulating layers 11, 12, and 13 described above. Moreover, a copper thin plate, an aluminum thin plate, etc. can be used as the carrier member 43U and the carrier member 43L.

Each of the resistance members 39 _j (j = 1 to 3) includes at least one columnar member 33 _jk (k = 1,...). As shown in FIG. 3B, each of the columnar members 33 _jk includes a columnar resistor 31 _jk formed on the + Z direction side surface of the conductor film 42U, and a + Z direction side end of the resistor 32 _jk. It is comprised from the solder plating part 32 _jk formed in the part. Here, as a material of the resistor 31 _jk , nickel alloy, nichrome (nickel-chromium alloy), or the like can be used. The length of the resistor 31 _{jk in} the Z-axis direction is substantially the same as the thickness of the insulating layer 13 described above. In this embodiment, it is set to 100 μm. The diameter of the bottom surface of the resistor 31 _jk is arbitrary, but is preferably 5 to 200 μm in order to enable high mounting density.

  Next, the manufacturing process of the printed wiring board 10 will be described.

  First, the resistor module 40 is manufactured. In manufacturing the resistor module 40, first, a support member 41 is prepared (see FIG. 4A). The support member 41 is manufactured by pressing and attaching the carrier member 43U to the surface of the core member 44 on the + Z direction side and pressing and attaching the carrier member 43L to the surface of the core member 44 on the −Z direction side. .

  Next, the conductor film 42U is attached to the + Z direction side surface of the carrier member 41U of the support member 41 via an adhesive, and the conductor film 42L is attached to the −Z direction side surface of the carrier member 41L via an adhesive. (See FIG. 4B). Subsequently, the dry film resist 45U is laminated on the surface of the conductor film 42U on the + Z direction side, and the dry film resist 45L is laminated on the surface of the conductor film 42L on the −Z direction side (see FIG. 4C). Here, as the dry film resists 45U and 45L, an acrylic resin (for example, trade name HW4100 (Hitachi Chemical Co., Ltd.)) or the like can be used.

Next, the dry resist on the columnar member formation region on the surface on the + Z direction side of the conductor film 42U is removed to form the recesses 49 _jk (j = 1 to 3, k = 1,...), And the conductor in the columnar member formation region The + Z direction side surface of the film 42U is exposed (see FIG. 5A). The removal of the dry film resist on the resistance element formation region is performed by irradiating the dry film resist on the resistance element formation region with a laser beam having a predetermined power. Subsequently, the resistor 31 _jk is formed by plating on the surface in the + Z direction side of the conductor film 42U in the recess 49 _jk (see FIG. 5B).

Next, a solder plating portion 32 _jk is formed on the + Z direction side end face of the resistor 31 _jk by the following plating method to form a columnar member 33 _jk (see FIG. _6A ).

Next, the resistor 31 ₁ is formed on the conductor film 33 ₁ exposed as described above, using a plating method using a bath having a desired composition, PVD, CVD, or the like. In the case of the plating method, by appropriately adjusting the composition of the bath and the plating conditions (pH, temperature, current density and energization time in the case of electrolytic plating), a resistor having a desired plating thickness, that is, a resistance value 31 ₁ can be formed (see FIG. 5A). For example, using a nickel sulfate bath (pH 4 to 5) using a bath having the following composition, plating is performed under predetermined conditions, for example, at a temperature of 40 to 60 ° C. and a current density of about ² to 6 A / dm ² for 250 minutes. When performed, a resistor having an average thickness of about 100 μm can be formed.

  Subsequently, the dry film resist 45U is removed from the + Z direction side surface of the conductor film 42U, and the dry film resist 45L is removed from the −Z direction side surface of the conductor film 42L (see FIG. 6B). Thus, the resistor module 40 is manufactured.

Moreover, after laminating a dry film resist on the support member 36 ₂ and forming a conductor pattern, the resistance element 30 ₂ having different resistance values can be manufactured by the following plating method.

  Examples of such a dry film resist include HW440 (manufactured by Hitachi Chemical Co., Ltd.). Moreover, as a plating method, the electroless plating method using the plating bath of the following Table 2 can be mentioned.

A plurality of recesses 49 _i can be formed to form resistors having different resistance values, and gold, silver, chromium, iron, vanadium, or the like can be formed by physical vapor deposition (PVD), chemical vapor, or the like. may be by a vapor deposition method such as a phase growth method (CVD) is evaporated on the conductive film 33 ₁ in the + Z direction side surface to form a resistor.

  After manufacturing the resistor module 40 as described above or in parallel with the manufacture of the resistor module 40, the conductor film 42A is attached to the + Z direction side surface of the carrier member 43A by an adhesive as shown in FIG. The affixed member 48 is manufactured. Here, as the material of the carrier member 43A, the same material as that of the carrier members 43U and 43L can be used. Further, as the material of the conductor film 42A, the same material as that of the conductor films 42U and 42L can be used. The adhesive used for bonding the carrier member 43A and the conductor film 42A is the same as that used for bonding the carrier members 43U and 43L and the conductor films 42U and 42L.

Next, on the + Z direction side surface of the conductor film 42A of the member 48, an insulating material is applied so as to have a predetermined thickness in order to form the insulating layer 13. Such an insulating material has a high temperature immediately after application and is in a softened state. While maintaining the softened state by heating the insulating material as necessary, the + Z direction side surface of the insulating material and the resistance member 39 _j of the resistor module 40 described above face each other, so that the resistor module 40 is crimped to a soft insulating material.

As a result, the solder plating section 32 _jk of each columnar member 33 _jk resistance element 39 _j reaches the + Z direction side surface of the conductor film 42A, an electrical and a resistor 31 _jk and the conductor film 42A of the columnar member 33 _jk Connected to. Since the solder plating portion 32 _jk is integrated with the conductor film 42A by this pressure bonding, the solder plating is performed in FIGS. 1 and 2 described above and FIGS. 7B, 7C, and 8 described later. _Illustration of the connection part by the part 32 _jk is omitted.

Subsequently, the whole is cooled to cure the softened insulating material, thereby forming the insulating layer 13. As a result, the resistor 31 _jk is embedded in the insulating layer 13, the + Z direction side end of the resistor 31 _jk is electrically connected to the conductor film 42U, and the −Z direction side end of the resistor 31 _jk is the conductor film 42A. The resistor module 40 is fixed to the insulating layer 13 in an electrically connected state (see FIG. 7B).

  Next, the portion (that is, the carrier member 43U, the core member 44, the carrier member 43L, and the conductor film 42L) on the + Z direction side of the conductor film 42U of the resistor module 40 and the carrier member 43A of the member 48 are removed to remove the member 55. Is manufactured (see FIG. 7C). Subsequently, a resist 47U is formed in a region where the above-described conductor pattern 23 is to be formed on the surface of the conductor film 42U of the member 55 on the + Z direction side by a known photolithography method, and the −Z direction of the conductor film 42A of the member 55 is formed. A resist 47L is formed in the region where the above-described conductor pattern 22 is to be formed on the side surface (see FIG. 8A).

Next, the conductive film 42A and the conductive film 42U are selectively removed by a well-known etching method to form the conductive pattern 22 and the conductive pattern 23. Then, the resist 19 is removed, and the member 50 containing the resistance element _30j is formed. Is obtained (see FIG. 7B). Here, in the etching for manufacturing the member 50, the resistor 31 _jk in the resistance element 30 _j has the conductor pattern 22 on the −Z direction side and the conductor pattern 23 on the −Z direction side, And since it is embedded in the insulating layer 13, it is not eroded by etching. As a result, the resistance element 30 _j having the resistance value planned at the time of manufacturing the resistor module 40 formed based on the design value is mounted on the member 50.

  In parallel with the manufacture of the member 50 described above, the member 51 in which the conductor pattern 21 is formed on the + Z direction side surface of the insulating layer 11 is manufactured (see FIG. 8C). The member 51 is manufactured by, for example, forming the conductor pattern 21 by a known photoetching method using a copper clad laminate as a starting material. And the printed wiring board 10 is manufactured by laminating | stacking the member 50 on the + Z direction side surface of the member 51 through the insulating layer 12 (refer FIG.8 (D)).

  Although not described above, via holes for interlayer wiring are appropriately formed in the printed wiring board 10.

As described above, in the printed wiring board 10 of the present embodiment, the resistor 31 _jk that constitutes the resistance element 30 _j and determines the resistance value is embedded in the insulating layer, and the −Z direction side end is the insulating layer 13. While being electrically connected to the conductor pattern 22 formed on the −Z direction side surface, the + Z direction side end is electrically connected to the conductor pattern 23 formed on the + Z direction side surface of the insulating layer 13. For this reason, even if a photoetching method or the like is used when forming the conductor pattern 22 or the conductor pattern 23, the resistor _31jk is not eroded by etching. The resistor element 30 _j includes a columnar resistor 31 _jk extending along a direction penetrating the insulating layer 13. For this reason, planar mounting density can be improved. Therefore, according to the printed wiring board 10 of the present invention, it is possible to realize a printed wiring board in which a resistive element having a highly accurate resistance value is incorporated with high mounting efficiency.

Further, in the printed wiring board 10 of the present embodiment, when the resistance element 30 _j includes a plurality of resistors 31 _jk configured in the same manner, the conductor pattern 22 and the conductor pattern according to the resistance value of the resistance element 30 _j. 23, the resistor 31 _jk is electrically connected in at least one of a series and a parallel manner to form the resistor element 30 _j . Therefore, it is possible to easily realize a printed wiring board in which the resistance element 30 _j having a desired resistance value is built.

In addition, the resistor module 40 of the present embodiment includes a support member 41, a conductor film 42U disposed on the + Z direction side surface of the support member 41, and a resistor 31 formed on the + Z direction side surface of the conductor film 42U. and a resistance member 39 _j including _jk . Therefore, the columnar member 33 _jk including the resistor 31 _jk is bonded to the insulating layer 13 in the softened state by pressing the insulating layer 13 so that the resistor 31 _jk faces the insulating layer 13. It penetrates and is electrically connected to the conductor film 42A formed on the side opposite to the resistor module side of the insulating layer 13. Then, after the insulating layer 13 is cured, the support member 41 is removed, and the conductive films 42A and 42U are etched by a photo-etching method or the like to be fixed to form the desired conductor patterns 22 and 23. The printed wiring board 10 of this embodiment can be easily manufactured.

Further, in the resistor module 40 of the present embodiment, the solder plating portion 32 which is a connecting conductor portion for electrically connecting to the conductor member at the end of the resistor 31 _jk opposite to the conductor film 42U side. _jk is formed. Therefore, the electrical connection between the resistor 31 _jk and the conductor film 42U can be easily performed.

  The resistors manufactured as described above can be accommodated in a small area regardless of the level of the resistance value, and since they are built in the substrate, electronic devices such as LSI can be mounted on these resistors. .

  In addition, since the manufactured resistor is columnar, the resistance value can be easily adjusted. That is, it is possible to wire the resistors in series so that the resistance value is higher than the desired resistance value in advance, and to connect a part of the resistors in parallel so as to obtain the desired resistance value. On the contrary, it goes without saying that the resistance can be increased by connecting in advance in parallel and cutting the circuit.

  Further, instead of the resistor module 40, a resistor module 40 'in which the support member 41 is changed to a support member 41' formed of a copper thin plate, an aluminum thin plate, or the like as shown in FIG. 9 may be used. In addition, the conductor film 42 in FIG. 9 is comprised similarly to the conductor films 42U and 42L mentioned above.

Further, in the above embodiment, the shapes of the resistors 31 _jk are all the same, and the resistance values of the resistors 31 _jk are all the same, but by individually setting the diameters of the bottom surfaces of the resistors 31 _jk , Each of the resistors 31 _jk may have a specific resistance value.

In addition, after the resistor module 40 is manufactured, the resistance value of each resistor 31 _jk may be measured to check whether it is within the allowable accuracy range. The resistor module 40 is prototyped under various process conditions, the resistance values of the resistors 31 _{jk of} the prototyped resistor module 40 are measured, and process conditions that fall within the allowable accuracy range may be obtained in advance. Good.

In the above embodiment, the laser beam is irradiated to the dry film resist 49U when forming the concave portion 49 _jk , but a well-known photolithography method used in the manufacture of semiconductor elements can also be used.

  In addition, a member 55 ′ (see FIG. 11C) equivalent to the member 55 in the manufacturing process of the printed wiring board 10 of the above embodiment may be manufactured by the following manufacturing process. That is, first, as shown in FIG. 10A, a member 65 is prepared in which the conductor layer 67U is formed on the + Z direction side surface of the insulating layer 66 and the conductor layer 61L is formed on the −Z direction side surface. To do. Here, the material of the insulating layer 66 is the same as that of the insulating layer 13 described above, the material of the conductor layer 67U is the same as the material of the conductive film 42U described above, and the material of the conductor layer 67L. The same material as that of the conductor film 42L described above is used.

In parallel with the preparation of the member 65, the low melting point conductor layer 62U is formed on the + Z direction side surface of the resistance material layer 61 and the low melting point is formed on the −Z direction side surface as shown in FIG. A member 60 on which the conductor layer 62L is formed is prepared. Here, the resistance material layer 61 is formed of the same material as that of the resistor 31 _jk described above, and has substantially the same thickness in the Z-axis direction as that of the insulating layer 66. The material of the low melting point conductor layers 62U and 62L has a melting point lower than that of the material of the resistance material layer 61, the material of the insulating layer 66, and the material of the conductor layers 67U and 67L, and is substantially the same as the conductor layers 67U and 67L. It has a thickness in the Z-axis direction. In addition, as the material of the low melting point conductor layers 62U and 62L, a material having high weldability to the conductor layers 67U and 67L is used. This is because it is easy to ensure electrical continuity between the low melting point conductor layers 62U and 62L and the conductor layers 67U and 67L in a punched piece of the member 65 described later. When the material of the conductor layers 67U and 67L is Cu metal, Sn metal can be used as the material of the low melting point conductor layers 62U and 62L.

  Next, the member 65 and the member 60 are placed on the + Z direction side surface of a base (not shown), and are sequentially placed on the + Z direction side surface of the die 70 having the opening 71. And the punching means 75 is arrange | positioned in the position of the + Z direction of the opening part 71 on both sides of the member 65 and the member 60 (refer FIG.10 (C)). Here, the thickness of the die 70 in the Z-axis direction is substantially the same as the thickness of the member 60 in the Z-axis direction (that is, the thickness of the member 65 in the Z-axis direction).

  Subsequently, by moving the punching means 75 in the −Z direction, the member 65 and the portion of the member 60 at the −Z direction position of the punching means 75 are punched, and the punched piece of the member 65 is embedded in the member 60 (FIG. A)). The embedding of the member 65 into the member 60 is performed at a desired XY position in the member 60. Then, the punched piece of the member 65 embedded in the member 60 is taken out and heated, and the low melting point conductor layers 62U and 62L of the punched piece are welded to the conductor layers 67U and 67L. Thereafter, a member 55 'equivalent to the member 55 is manufactured by cooling the punched piece of the member 65 embedded in the member 60 (see FIG. 11B).

  Thereafter, the member 55 ′ is used in place of the member 55, and the same processes as in FIGS. 8A to 8D are performed, so that the printed wiring equivalent to the printed wiring board 10 of the above embodiment is obtained. A board can be manufactured.

    The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Example 1)
(1) Production of resistor module As a material of the core member, a glass cloth impregnated with an epoxy resin was used, and a copper thin plate was used as a carrier member. A copper film having a thickness of 5 μm was used as the conductor film.

  First, a carrier member was laminated on both surfaces of the core member and subjected to press treatment to produce a support member. Next, the conductor film was bonded to both surfaces of the support member using VERZONE (Daiwa Kasei Co., Ltd., SF-310) so that they could be peeled later, to produce a resistor module.

  Next, a dry film resist (HW4100, manufactured by Hitachi Chemical Co., Ltd.) is laminated on both sides of the support member produced as described in (1) above, and a dry film resist having a diameter of 10 μm is irradiated by laser beam irradiation. 20 × 20 lines were removed at intervals of 50 μm pitch to form recesses.

Next, using a nickel sulfate bath having the composition shown in Table 1 above, plating was carried out for 250 minutes under the conditions of pH 4-5, 40-60 ° C., 2-6 A / dm ² , and the recesses formed as described above were averaged. A resistor having a thickness of 100 μm was formed.

  Thereafter, the dry film resist was removed by irradiating both surfaces of the support member with a laser beam to form a resistor module. The resistor manufactured here had a phosphorus content of 11% by weight.

(2) Embedding of resistor module and conductive connection The above copper film having a thickness of 5 μm is bonded to one surface of the copper thin plate as a carrier member using VERZONE (manufactured by Yamato Kasei Co., Ltd., SF-310). did.

  An epoxy resin was applied to the surface of the bonded copper film, and the resistor module produced as described above was pressure-bonded to the softened resin.

  Next, the whole was cooled to cure the epoxy resin, and the resistor module produced as described above was fixed.

(3) Manufacture of member with built-in resistance element The carrier member, core member, and conductor film other than the insulating layer of the epoxy resin in which the resistor is embedded and the copper film adhered to both sides thereof are removed, and the member 55 is removed. Manufactured. A resist was formed on the surface of each of the copper films of the member 55 by a photolithography method in a region where a conductor pattern was to be formed.

  A conductor pattern was formed by etching, the resist was removed, and a member 50 incorporating a resistance element was manufactured.

  In parallel with the manufacture of the member 50, photoetching was performed on the copper-clad laminate to manufacture the member 51. An insulating layer was formed on the conductor pattern formed on the member 51 by using the epoxy resin, and the insulating layer and the member 50 were laminated to manufacture a printed wiring board on which a resistive element was mounted. The resistance element mounted on this printed wiring board is a resistor having a bottom surface diameter of 10 μm, an array pitch of 50 μm, a total of 400 20 rows × 20 columns, and a resistance value of 1.35 Ω (design value). The resistance value is 540 Ω (design value).

(Example 2)
In the same manner as in Example 1 except that the diameter of the bottom surface of the resistor is 50 μm, the arrangement pitch is 100 μm, and the number is 10 rows × 10 columns, one 0.54Ω (design value) is connected in series. A resistance element having a resistance value of 5.4Ω (design value) was mounted.

As described above, a printed wiring board having a resistance value (design value) of 540Ω or 5.4Ω mounted on a small area of 1 × 1 mm ² could be manufactured. Further, the temperature change rates of the resistance values of these resistance elements were very small, 45 ppm / ° C. and 54 ppm / ° C., respectively, and were excellent in stability. The rated power was equivalent to 1/8 W and 1/2 W, respectively, and was comparable to general chip parts.

  Further, when the variation of the resistance value of each of the 200 resistance elements was examined, ± 3σ / [average resistance value] (where σ represents a standard deviation), ± 8.9% and ± 6.7, respectively. %, And it became clear that resistance elements with very small variations in resistance values were formed.

(Comparative Example 1)
A resistance element having a resistance value of 2,300Ω (design value) was formed by screen printing using a carbon resin.

(Change in resistance value)
About the resistance element manufactured by said Example 1, 2 and the comparative example, the oil dip test was done on the following conditions, and the change of normal temperature resistance value was measured. After being left at room temperature for 5 minutes, it was immersed in 260 ° C. oil for 5 minutes and left at room temperature for 5 minutes. One cycle was 900 cycles. The results are shown in Table 3.

  As shown in Table 3, it is possible to manufacture a highly accurate resistance element having a high resistance value of 548Ω with respect to the design value of 540Ω and a low resistance value of 5.43Ω with respect to the design value of 5.4Ω. Has been demonstrated.

  Further, as shown in Table 3, the resistance value of the resistance element of Comparative Example 1 decreased by nearly 50% after the oil dip test of 900 cycles. On the other hand, the resistance element of the present invention has a very small change in resistance value of −0.7 to −1.3% even after performing an oil dip test of 900 cycles, and is highly reliable. Indicated.

(Example 3)
A printed wiring board including a resistance element made of a metal shown in Table 4 below was manufactured in the same manner as in Examples 1 and 2 except that the composition of the plating bath and the plating conditions were changed, and the resistance value was measured.

  About the printed wiring board provided with each metal resistance element shown in Table 4, the same oil dip test as the printed wiring board provided with the resistance element manufactured in Examples 1 and 2 and Comparative Example 1 was performed. As a result, in the printed wiring board including the resistance element manufactured with any metal, the change rate of the resistance value was a small value of less than 3% regardless of the resistance value.

Example 4
Resistive elements were manufactured in the same manner as in Examples 1 and 2 except that the phosphorus content in the plating bath during resistor formation was changed. This resistance element was exposed to a high temperature atmosphere (150 ° C., 500 hours), and the subsequent change in resistance value was measured. The results are shown in Table 5 and FIG.

  As shown in Table 5 and FIG. 12, when the phosphorus content is 3%, when exposed to a high temperature atmosphere for 500 hours, the resistance change rate exceeds 5% regardless of whether the resistance is high resistance or resistance, and stability is improved. It was shown that there was a problem. When the phosphorus content was 17%, the rate of change was less than 5% in the case of resistance, but it exceeded 5% in the case of high resistance, so it was thought that there was still a problem in stability.

  On the other hand, when the phosphorus content was 5 to 15%, even after exposure to a high temperature atmosphere for 500 hours, the change in resistance value was as low as 5% or less, indicating high stability. From this, it was shown that the optimal phosphorus content is 5 to 15%.

  The printed wiring board of the present invention can be applied to a built-in printed wiring board with high mounting efficiency.

It is sectional drawing which shows the schematic structure of one Embodiment of the printed wiring board which concerns on this invention. It is a figure for demonstrating the structural example from which the resistance value of the resistor in FIG. 1 was changed. It is a figure which shows schematic structure of one Embodiment of the resistor module used for manufacture of the printed wiring board in FIG. FIG. 4 is a view (No. 1) for explaining a production step of the resistor module of FIG. 3; FIG. 4 is a view (No. 2) for explaining a production step of the resistor module of FIG. 3; FIG. 6 is a view (No. 3) for explaining a production step of the resistor module of FIG. 3; FIG. 3 is a view (No. 1) for describing a manufacturing process of the printed wiring board of FIG. 1; FIG. 3 is a diagram (part 2) for explaining a manufacturing process of the printed wiring board in FIG. 1; It is a figure for demonstrating the modification of a resistor module. It is FIG. (1) for demonstrating the modification of the manufacturing process of a printed wiring board. It is FIG. (2) for demonstrating the modification of the manufacturing process of a printed wiring board. It is a graph which shows the change of resistance value after exposing to phosphorus content and high temperature atmosphere.

Explanation of symbols

10 ... printed circuit board, 11, 12, 13 ... insulating layer, 21, 22, 23 ... conductive pattern 30 _1, 30 _2, 30 ₃ ... resistance element, 31 _1, 31 _2, 31 ₃ ... resistors, 32 ₁ , 32 ₂ , 32 ₃ ... Solder plating portion (conductor portion for connection), 40, 40 '... resistor module, 41, 41' ... support member, 42, 42U, 42L, 42A ... conductor film.

Claims (4)

An insulating layer;
A first conductor pattern formed on one surface of the insulating layer;
A second conductor pattern formed on the other surface of the insulating layer;
The one end is embedded in the insulating layer and electrically connected to the first conductor pattern, and the other end has at least one resistor electrically connected to the second conductor pattern. A printed wiring board comprising: a resistance element; The resistor has a plurality of the resistors electrically connected in at least one of a series and a parallel manner by the first conductor pattern and the second conductor pattern according to the resistance value. The printed wiring board according to claim 1. The resistor is mainly composed of at least one metal selected from the group consisting of nickel, cobalt, chromium, indium, lithium, titanium, tin, tantalum, platinum, iron, palladium, vanadium, and zirconium. The printed wiring board according to claim 1 or 2. The printed wiring according to any one of claims 1 to 3, wherein the resistor is formed by nickel-phosphorous plating containing phosphorus of 5 to 15% by weight of the total weight of plating. Board.

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