JP2007067035A - Resistive element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a resistive element which shows a high electric resistance characteristic even if it is placed under a heating environment and can highly precisely be formed in a small size. <P>SOLUTION: The manufacturing method of the resistive element having an element electrode and a resistance layer is provided with (a) a resistance film forming process for depositing the resistance layer on a substrate, by an electroless plating method using non-electrolyzed nickel phosphorous plating liquid containing nickel salt, reducing agent and complexing agent; (b) a first acid processing process for performing a first acid processing on the resistance layer; and (c) a second acid processing process for performing a second acid processing on the resistance layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resistance element using a plating resistance film and a method for manufacturing the resistance element.

In recent years, as devices such as mobile phones and digital cameras have become smaller and lighter, it is difficult for conventional devices to be mounted on printed wiring boards using conventional mounting technologies such as reducing the size of devices and reducing the distance between devices. Therefore, a printed wiring board incorporating these elements is required.
Further, there is a demand for an element capable of sufficiently satisfying characteristics with a thin component or a film element in order to prevent the substrate containing the element from becoming thick.
As a method of forming a resistance element on a printed wiring board, a method of forming a resistance layer with a metal thin film on a copper foil, a method of forming a resistance layer on a substrate by electroless plating, or printing a resistive thick film polymer There are methods.

In consideration of the resistance value, accuracy, shape, price, etc., it is necessary to select a forming method according to the application.
In the method of printing a thick film polymer, it is possible to form a high-resistance material, but it is difficult to form a fine size.

The thin film type using a metal material is restricted to a low resistance range compared to the thick film type, but can be formed with a small size and high accuracy.
Here, a method of forming a resistance element with a metal thin film on a copper foil is, for example, by forming a thin film resistance layer on a copper foil by electrolytic nickel / phosphorous plating on a substrate and forming each of the resistance elements. A resistance element is used as an electrode and a resistance film (see, for example, Patent Document 1).
In addition, the method of forming the resistance element by plating on the substrate is, for example, after forming a wiring pattern in which a part of the wiring is separated on the substrate, and then electroless nickel / phosphorous plating between the partially separated wirings. Thus, a resistance layer is formed to form a resistance element (see, for example, Patent Document 2).
US Pat. No. 4,808,967 JP-A-10-190183

However, a resistance element made of a nickel-phosphorus thin film formed by conventional electroless plating is effective as a high-precision resistance element with a small size, but when it is placed in a heating environment, it has high electrical resistance characteristics ( It was difficult to maintain the sheet resistance value.
For this reason, there is a demand for the development of a highly accurate resistive element that exhibits stable electrical resistance characteristics even in various applications placed under a heating environment, and that has a small size.

The present invention has been made in view of the above circumstances, and even when placed in a heating environment, a resistance element that exhibits high electrical resistance characteristics and can be formed with high accuracy in a small size is obtained. It is an object of the present invention to provide a resistance element comprising a nickel-phosphorus thin film and a method for manufacturing the resistance element.

In order to solve the above-mentioned problem, the invention according to claim 1
The resistive layer of the resistive element comprising the element electrode and the resistive layer,
A resistance film forming step of forming a resistance film on a substrate by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent and a complexing agent;
A first acid treatment step of subjecting the formed resistance film to a first acid treatment;
Next, a second acid treatment step for subjecting the resistance film to a second acid treatment;
A method of manufacturing a resistance element.

  The invention according to claim 2 is the method of manufacturing a resistance element according to claim 1, wherein a heat treatment step of further performing a heat treatment is performed after the second acid treatment step.

The invention according to claim 3 includes a resistance film forming step of forming a resistance film on the entire surface of the substrate by plating, a conductor layer forming step of forming a conductor layer on the formed resistance film, and the resistance film and the conductor layer. In the method of manufacturing a resistance element for forming a resistance layer, a wiring pattern forming step for patterning, etching a predetermined portion of the conductor layer, exposing a resistance film under the conductor layer,
The resistive layer is
A resistance film forming step of forming a resistance film on a substrate by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent and a complexing agent;
A first acid treatment step of subjecting the formed resistance film to a first acid treatment;
Next, a second acid treatment step for subjecting the resistance film to a second acid treatment;
A method of manufacturing a resistance element.

  The invention according to claim 4 is the method of manufacturing a resistance element according to claim 4, wherein after the second acid treatment step, a heat treatment step of further performing a heat treatment is performed.

The invention according to claim 5 is the method of manufacturing a resistance element according to claim 3 or 4, wherein the resistance film formed on the substrate is patterned.

In the invention according to claim 6, on the substrate on which the wiring electrode layer patterned in advance is formed,
A resistance film forming step of forming a resistance film on a substrate by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent and a complexing agent;
A first acid treatment step of subjecting the formed resistance film to a first acid treatment;
Next, a second acid treatment step for subjecting the resistance film to a second acid treatment;
A method of manufacturing a resistance element.

  The invention according to claim 7 is the method of manufacturing a resistance element according to claim 6, wherein a heat treatment step of further performing a heat treatment is performed after the second acid treatment step.

The invention according to claim 8 is a resistance element having a resistance layer formed by the method according to any one of claims 1 to 7.

The invention according to claim 9 is a wiring board comprising the resistance element according to claim 8 mounted on a substrate.

According to the present invention, a nickel / phosphorous thin film formed by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent, and a complexing agent and subjected to different acid treatments as a resistance layer. Therefore, it has much higher electric resistance than nickel / phosphorus thin film formed by conventional electroless plating method, and it does not involve chromium eutectoid, and it also has electric resistance due to heat. Can be prevented.
Further, by further heat-treating the resistance layer, the thermal stability of the electrical resistance characteristics of the resistance layer is improved, and stable electrical resistance characteristics are exhibited even in various applications placed in a heating environment. Can do.

  The resistance element manufacturing method according to the present invention includes forming a resistance film on a substrate by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent and a complexing agent. In the acid treatment step and the second acid treatment step, a resistance element having a high sheet resistance value can be produced by acid treatment or further heat treatment.

  The substrate on which the resistance element of the present invention is formed is not particularly limited, and may be a rigid sheet or flexible sheet made of various synthetic resins, a glass plate, a ceramic plate, or a metal substrate having an insulating layer on the surface. These can be selected and used as appropriate according to the application. In addition, a wiring circuit or other passive elements may be previously formed therein.

The electroless nickel / phosphorous plating solution for forming a resistance film is a plating solution containing a complexing agent. Examples of the complexing agent include α-alanine, β-alanine, diethylenetriamine, L-glutamate, glycine, Examples include amino acids and amines containing amino groups (-NH2,> NH) such as triethylenetetramine, tetraethylenepentamine, monoethanolamine, and diethanolamine.
In particular, an amino group-containing compound selected from the group consisting of α-alanine, β-alanine, diethylenetriamine, L-glutamate and glycine is preferably used as the complexing agent.
The concentration of such a complexing agent in the plating solution can be about 0.1 to 2.0 mol / L, preferably about 0.5 mol / L to 1.5 mol / L.
Here, when the concentration of the complexing agent is less than 0.1 mol / L, the bath stability is lowered, and when it exceeds 2.0 mol / L, the deposition rate is undesirably slowed. The ratio of the complexing agent to the nickel concentration (mol / L) in the plating solution is preferably in the range of 1: 1 to 20: 1. When the ratio of the complexing agent is less than the above range, the sheet resistance of the formed nickel / phosphorus thin film becomes insufficient, which is not preferable.

  Nickel sulfate, nickel chloride, nickel hypophosphite, nickel carbonate, etc. can be used as the nickel salt constituting the nickel / phosphorous plating solution used in the present invention. The concentration of the nickel salt in the plating solution can be about 0.01 to 1.0 mol / L, preferably about 0.05 to 0.2 mol / L. When the concentration of the nickel salt is less than 0.01 mol / L, the deposition rate is slow, and when it exceeds 1.0 mol / L, the bath stability is undesirably lowered.

  As the reducing agent constituting the nickel / phosphorous plating solution used in the present invention, sodium hypophosphite, dimethylboraneamine, hydrazine and the like can be used. The concentration of the reducing agent in the plating solution can be about 0.05 to 1.0 mol / L, preferably about 0.1 to 0.3 mol / L. When the concentration of the reducing agent is less than 0.05 mol / L, the deposition rate is slow, and when it exceeds 1.0 mol / L, the bath stability is undesirably lowered.

Formation of the nickel / phosphorus thin film by the electroless plating method using the above electroless nickel / phosphorous plating solution can be performed, for example, under conditions of a bath temperature of 60 to 90 ° C. and a bath pH of 4 to 7. If the bath temperature is less than 60 ° C, the deposition temperature is slow, and if it exceeds 90 ° C, the bath stability is lowered, which is not preferable. On the other hand, if the bath pH is out of the above range, the film formation rate and the sheet resistance become insufficient, which is not preferable.
The nickel-phosphorus thin film formed by the electroless plating method using the above electroless nickel-phosphorous plating solution is nickel formed by the conventional electroless plating method, although it does not involve chromium eutectoid. -It has a much higher electric resistance characteristic than a phosphorus thin film.

The resistance element of the present invention further improves the electrical resistance characteristics of the resistance layer by subjecting the resistance layer formed using the electroless nickel / phosphorous plating solution to different acid treatment or further heat treatment. The thermal stability is improved and the electrical resistance characteristics are prevented from deteriorating due to heat. Although the mechanism of thermal stabilization of the electrical resistance characteristics by the above treatment is unknown, a resistance layer having a high sheet resistance value can be obtained by acid treatment not only after acid treatment but also after heating at 200 ° C. For this reason, the resistance element of the present invention can exhibit stable electric resistance characteristics even when used in various applications placed in a heating environment.
In the present invention, the sheet resistance value after heating the resistance layer at 200 ° C. means that the resistance layer is left in an atmosphere at 200 ° C. for 30 minutes, and then the four-end needle method (Loresta MPMCP-T350 manufactured by Mitsubishi Chemical Corporation) is used. It means what was measured using.

Acids used for the first acid treatment and the second acid treatment include nitric acid, sulfuric acid, boric acid, carbonic acid, nitrous acid, silicic acid, borosilicic acid, phosphoric acid, phosphorous acid, hypophosphorous acid, sulfurous acid, persulfate. Inorganic acids such as sulfuric acid, hydrogen sulfide water, hydrofluoric acid, borohydrofluoric acid, hydrochloric acid, chlorous acid, hypochlorous acid, perchloric acid; formic acid, acetic acid, propionic acid, lauric acid, myristic acid, palmitic acid , Stearic acid, arachidic acid, acrylic acid, crotonic acid, oleic acid, linoleic acid, linolenic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid Examples thereof include organic acids such as acid, maleic acid, lactic acid, malic acid, tartaric acid and citric acid.
As the acid treatment method, immersion in an acid aqueous solution, spraying of an acid aqueous solution, or the like can be used.
Here, in the case of acid treatment by immersion, the acid aqueous solution may be stirred.
By performing the first acid treatment in this manner, the sheet resistance value of the resistance layer after the acid treatment is increased as compared with the sheet resistance immediately after the electroless plating. And it can adjust to a desired sheet resistance value by performing the 2nd acid treatment.
For example, the first acid treatment step is performed with a hydrochloric acid solution, and the second acid treatment step is performed for fine adjustment of the resistance value. The acid treatment has a smaller influence on the plating film than the first acid treatment. It is desirable to do. For example, an ammonium persulfate solution is suitable.

The resistance element of the present invention also has an effect of further increasing the sheet resistance value by performing heat treatment depending on the type of complexing agent constituting the electroless nickel / phosphorous plating solution. For example, when diethylenediamine is used as the complexing agent, the sheet resistance value is remarkably increased by performing the heat treatment after the acid treatment. On the other hand, when L-glutamate is used as the complexing agent, the sheet resistance value is stable even after heat treatment. Therefore, the resistance element of the present invention can arbitrarily set the sheet resistance value provided after the heat treatment by appropriately selecting the complexing agent used in the electroless nickel / phosphorous plating solution. Said heat processing can be performed within the range of 100-850 degreeC, for example.

Next, a method for incorporating the resistance element of the present invention in a printed wiring board will be described. In order to incorporate the resistance element of the present invention in a printed wiring board, a resistance layer formed in a predetermined resistance element formation region and two conductor layers in contact with the resistance layer are formed. The two conductor layers are separated from each other and can be used as an element electrode of a resistance element. As a material for the conductor layer, a metal material having good conductivity such as gold, silver, copper, nickel, and aluminum is preferable.

Hereinafter, a method for forming a resistance element on a substrate will be described as an example. Here, in a state where the resistance element is completed, a region where the resistance layer is formed is defined as a resistance element formation region, a region where a conductor layer to be an element electrode is formed is defined as an element electrode formation region, and two conductor layers are separated. The following description will be made assuming that the region where the resistance layer is exposed is an element electrode isolation region.

A first method for incorporating the resistance element in the printed wiring board includes the following steps (A-1) to (C-1) (see FIG. 1).
(A-1) is a step of forming the resistance layer 2 on the entire surface of the substrate 1 by plating (see FIG. 1A).
(B-1) is a step of forming the wiring pattern 4 including the resistance layer 2 and the conductor layer 3 ′ after forming the conductor layer 3 on the substrate 1 (FIG. 1B to FIG. d)).
(C-1) is a step of etching a predetermined portion of the conductor layer 3 ′ to expose the resistance layer 2 under the conductor layer 3 ′ (see FIGS. 1E to 1F). ).

Here, the step (A-1) is performed as a resistance film forming step (a) for forming a nickel / phosphorus thin film to be the resistance layer 2 using the above-described electroless nickel / phosphorous plating solution.
The acid treatment steps (b) and (c) can be performed at any stage as long as the resistance layer 2 is exposed as long as the acid used for the acid treatment does not affect the conductor layer 3. .
For example, it may be performed between step (A-1) and step (B-1), may be performed between step (B-1) and step (C-1), or may be performed between step (C- It may be performed after 1).
When the acid treatment steps (b) and (c) are performed between the step (A-1) and the step (B-1), the conductor layer 3 is not formed at this stage. Regardless of the material, it is preferable because the acid used for the acid treatment can be freely selected.
Further, when the acid treatment step is performed between the stage shown in FIG. 1A and the stage shown in FIG. 1B, the entire surface of the resistance layer 2 is exposed, so that the treatment is performed uniformly. And it is most preferable because the influence on the conductor layer 3 need not be taken into consideration.
Further, when trimming is performed during the manufacturing process, the acid treatment process is preferably performed before the trimming process because the resistance value can be adjusted in a stable state.
When the heat treatment step (d) is performed, it may be performed at any stage after the acid treatment step (c), or may be performed between the step (A-1) and the step (B-1). And you may carry out between a process (B-1) and a process (C-1), and may carry out after a process (C-1). When trimming is performed, it is preferable to perform the heat treatment step (d) before the trimming step in order to suppress the influence of heat generated during trimming.

In the step (B-1), the wiring pattern 4 in which the resistance layer 2 and the conductor layer 3 ′ are laminated is formed in the resistance element formation region 5. The resistance element forming region 5 is set in an appropriate shape such as a rectangle or a meander structure so that a desired resistance value can be obtained. After the completion of the step (B-1), the resistance layer 2 and the conductor layer 3 are removed and the substrate 1 is exposed outside the resistance element formation region 5 (see FIG. 1D).
Step (B-1) can be performed, for example, by sequentially performing the following procedures (1) to (3).
In step (1), the conductor layer 3 is formed on the entire surface of the resistance layer 2 (see FIG. 1B).
In step (2), a resist 10 is formed in the resistance element formation region 40 on the conductor layer 3 (see FIG. 1C).
In step (3), after removing the conductor layer 3 and the resistance layer 2 in a portion where the resist is not formed by collective etching, the resist 10 is removed (see FIG. 1D).

In the step (C-1), a predetermined portion of the conductor layer 3 is etched to expose the resistance layer 3 below the conductor layer 3. That is, while leaving the conductor layer 3 in the element electrode formation region to form the element electrode, the conductor layer 3 in the element electrode isolation region 50 is removed.
This step (C-1) can be performed, for example, by sequentially performing the following procedures (1) to (2).
In step (1), after the resist 12 is formed on the wiring pattern 4 and the substrate 1, the resist 12 in the element electrode isolation region 50 is removed by patterning to form a portion where no resist is provided (FIG. 1 (e)). )reference).
In the step (2), the portion of the conductor layer 3 where no resist is provided is etched, and then the resist 12 is removed (see FIG. 1F).
Here, when the conductor layer 3 is etched, it is desirable to use an etchant that hardly etches the resistance layer 2.
By carrying out the steps (A-1), (B-1) and (C-1), a resistance element 60 including the conductor layer 3 and the resistance layer 2 to be element electrodes is formed on the substrate 1. Is done.

A second method for incorporating the resistance element in the printed wiring board is a method including the following steps (A-2) to (B-2) (see FIGS. 2 to 5).
The step (A-2) is a step of forming the patterned resistance layer 2 on the substrate 1.
Step (B-2) is a step of forming the conductor layer 3 on the substrate 1.

Here, in the step (A-2), the resistance layer 2 is formed on the resistance element formation region 50 set on the substrate 1. The resistance element forming region 50 is set to an appropriate shape such as a rectangle or a meander structure so that a desired resistance value can be obtained. The substrate 1 is exposed outside the resistance element formation region 50.
When the resistance layer 2 is formed in the step (A-2), it is performed as a resistance film forming step (a) in which a nickel / phosphorus thin film to be a resistance layer is formed using the above-described electroless nickel / phosphorous plating solution.
The patterned resistance layer 2 may be formed by a method in which the resistance layer 2 is formed on the entire surface of the substrate 1 and then unnecessary portions are removed by etching or the like, or only a necessary portion on the substrate 1 is resisted. A method of forming the layer 2 by plating may be used.

The acid treatment steps (b) and (c) can be performed at any stage as long as the acid used for the acid treatment does not affect the conductor layer 3.
In the case of the method in which the unnecessary portion is removed by etching or the like after the resistance layer 2 is formed by plating on the entire surface of the substrate, it is preferable to perform the acid treatment in a state where the resistance layer 2 is plated on the entire surface so that the processing can be uniformly performed .
Moreover, in the case of the method of forming the resistance layer 2 only on a necessary portion, the method before forming the conductor layer 3 is preferable because the acid used for the acid treatment can be freely selected regardless of the material of the conductor layer 3.
When the heat treatment step (d) is performed, it may be performed at any stage after the acid treatment step (c), may be performed before the step (B-2), or may be performed in the step (B-2). ) May be followed.
When trimming is performed, it is preferable to perform the heat treatment step (d) before the trimming step in order to suppress the influence of heat generated during trimming.

As a method of forming the resistance layer 2 by plating on the entire surface of the substrate 1 and then removing unnecessary portions by etching or the like, for example, the following procedures (1a) to (4a) can be sequentially performed. (See FIG. 2).
In step (1a), the resistance layer 2 is formed on the entire surface of the substrate 1 (see FIG. 2A).
In step (2a), a resist 10 is formed in the resistance element formation region 50 on the resistance layer 2 (see FIG. 2B).
In step (3a), the portion of the resistance layer 2 where the resist is not provided is removed by etching (see FIG. 2C).
In step (4a), the resist 10 is removed (see FIG. 2D).

As a first method of forming a resistance layer only on a necessary portion on the substrate by plating, for example, the following procedures (1b) to (4b) can be sequentially performed (see FIG. 3).
In step (1b), a pd catalyst treatment (not shown) is performed on the entire surface of the substrate 1 (see FIG. 3A).
In step (2b), a resist 11 is formed on the entire surface of the substrate 1 excluding the resistance element formation region 50 (see FIG. 3B).
In step (3b), the resist layer 2 ′ is formed by plating on the portion of the substrate 1 where the resist is not provided (that is, in the resistance element forming region 50 (see FIG. 3C)).
In step (4b), the resist 11 is removed, and the substrate 1 is exposed to a portion other than the resistance element formation region 50 (see FIG. 3D).

As a second method of plating the resistance layer only on a necessary portion on the substrate by plating, there is a method of sequentially performing the following procedures (1c) to (3c) (not shown).
This method utilizes the effect that plating does not precipitate in the portion where the pd catalyst has been removed.
In step (1c), a pd catalyst treatment is performed on the entire surface of the substrate, and then a resist is formed in the resistance element formation region.
In step (2c), the portion of the substrate on which the resist is not formed is removed with the pd removing solution, and then the resist is removed. By this processing, the pd catalyst is left only in the resistance element formation region.
In step (3c), a resistance layer is plated on the substrate. At this time, since the resistance layer is not deposited on the portion where the pd catalyst is removed on the substrate, the resistance layer is formed only by plating on the resistance element forming region where the pd catalyst is left.

The step (B-2) is a step of forming the two conductor layers 3 in the element electrode formation region set so as to be in contact with the resistance layer 2 formed by patterning in the step (A-2). In order to separate the two conductor layers 3, the element electrode separation region 50 is set so as to overlap the resistance element formation region 50.
The said process (B-2) can be implemented by performing the following procedures (1d)-(5d) in order, for example (refer FIG. 4).
In the step (1d), a pd catalyst treatment (not shown) is performed on the entire surface of the patterned resistance layer 2 ′ and the exposed substrate 1 (see FIG. 4A).
In step (2d), a resist 11 is formed on the resistance layer 2 ′ in the element electrode isolation region 50. At this time, no resist is formed on the portion where the substrate 1 is exposed and on the resistance layer 2 where the conductor layer 3 (element electrode) is formed (see FIG. 4B).
In step (3d), the conductive layer 3 is plated on a portion of the substrate 1 where the resist is not formed, and then the resist 11 is removed (see FIG. 4C).
In step (4d), a resist 12 is formed on the conductor layer 3 on the device electrode formation region and the resistance layer 2 on the device electrode isolation region 50 (see FIG. 4D).
In step (5d), the conductive layer 3 where the resist 12 is not formed is removed by etching or the like, and then the resist 12 is removed (see FIG. 4E).

As described above, a resistance element including the resistance layer 2 ′ provided in the resistance element formation region 50 and the conductor layer 3 ′ (element electrode) provided in the element electrode formation region is formed on the substrate 1.
In the method shown in FIG. 4, the resist 12 is removed after the formation of the conductor layer 3 ′. However, not only the method but also the resist 12 is left, and in the step (4d), the conductor layer 3 ′ and the resist 11 (plating) are removed. A resist 12 (etching resist) can be formed on the resist). In this case, the step (3d) can be omitted.

As a 2nd method of performing a process (B-2), there exists the method of performing the following procedures (1e)-(5e) in order (refer FIG. 5).
In step (1e), a seed layer 25 is formed on the entire surface of the patterned resistance layer 2 ′ and the exposed substrate 1. The seed layer 25 may be any conductive material, and copper, silver, nickel, etc. formed by electroless plating are used (see FIG. 5A).
In step (2e), the resist 11 is formed on the seed layer 25 except for the element electrode formation region 70 (see FIG. 5B).
In step (3e), a conductor layer 3 ′ is formed by plating on the portion where the resist 11 is not formed (see FIG. 5C).
In step (4e), the resist 11 is removed. Thereby, the conductor layer 3 ′ can be formed only in the element electrode formation region 70 (see FIG. 5D).
In the step (5e), except for the protected seed layer 25 under the conductor layer 3 ′, the excess seed layer 25 is removed by etching (see FIG. 5E).
Since the seed layer 25 is made of a conductive material, it is integrated with the conductor layer 3 'to form an element electrode. Further, since the excess seed layer 25 on the resistance layer 2 ′ is removed in the element electrode isolation region 50, a short circuit between the conductor layers 3 ′ due to the seed layer 25 does not occur.
By the above procedure, a resistance element 60 composed of a resistance layer 2 ′ provided in the resistance element formation region 50 and a conductor layer 3 ′ (element electrode) provided in the element electrode formation region 70 is formed on the substrate 1. .

According to the above-described method for manufacturing a resistance element, it is possible to obtain a resistance element that exhibits high electrical resistance characteristics even when placed in a heating environment and can be formed with a small size and high accuracy.
In the method shown in FIG. 5, when removing the seed layer 25 in the step (5e), the seed layer 25 must be removed but the resistance layer 2 ′ must be processed (etched). .
The method shown in FIG. 5 requires fewer steps than the method shown in FIG. 4, but it is difficult to set conditions for removing the seed layer 25, so that the resistance layer 2 ′ is removed when the conductor layer 3 ′ is etched. The method shown in FIG.
However, the method shown in FIG. 5 can cope with the formation of finer wiring than the method shown in FIG.

As another method of forming the resistance element, there is a method of sequentially performing the following procedures (1f) to (6f) (see FIG. 6).
Step (1f) is a step of forming the resist pattern 10 only in the element electrode formation region 70 of the conductor layer 3 (copper foil) formed on the substrate 1 (see FIG. 6B).
Step (2f) is a step of using the resist pattern 10 to remove a portion where the resist pattern 10 is not formed by etching (see FIG. 6C).
Step (3f) is a step of removing the resist pattern 10 and exposing the conductive layer 3 ′ (element electrode layer) (see FIG. 6D).
Step (4f) is a step of forming a nickel plating layer 2 serving as a resistor on the entire surface of the substrate including the conductor layer 3 ′ (element electrode layer) (see FIG. 6E).
Step (5f) is a step of forming a resist pattern 12 in the resistance element formation region 50 (see FIG. 6 (f)).
The procedure (6f) is a step of removing the nickel plating layer in a portion other than the resistance element formation region 50 by etching (see FIG. 6H).
For the etching of the nickel plating layer 2, it is necessary to select a liquid that hardly etches the conductor layer 3 ′ (element electrode layer). Thereby, the resist pattern can be removed after etching, and the resistance element 60 can be formed.

Examples of the present invention and comparative examples will be described below.
In the following examples and comparative examples, the sheet resistance value of the resistance layer is measured by a four-end needle method (Loresta MPMCP-T350 manufactured by Mitsubishi Chemical Corporation).
Example 1
An electroless nickel / phosphorous plating solution having the following composition was prepared.
・ Nickel sulfate hexahydrate 26g / L
・ Diethylenetriamine (complexing agent) 0.27mol / L
・ Sodium hypophosphite monohydrate 30g / L
・ Lead nitrate 1mg / L
・ Ion exchange water remaining

Using the above-described plating solution, on a 0.4 mm-thick substrate 1 made of bismaleimide triazine resin (hereinafter referred to as BT resin) under the conditions of a bath temperature of 80 ° C. and a pH of 6.0, nickel / A resistance layer 2 made of a phosphorous thin film was formed on the entire surface (see step (A-1) and FIG. 1A).
The sheet resistance value immediately after the resistance layer 2 obtained by electroless plating was 200Ω / □.

A sulfuric acid aqueous solution having a concentration of 10% by volume was prepared using reagent grade 1 sulfuric acid. And the BT resin substrate 1 which has the said resistance layer 2 on the whole surface was immersed in the said sulfuric acid aqueous solution for 10 minutes at room temperature, and the 1st acid treatment was performed.
The sheet resistance value of the resistance layer 2 after the first acid treatment was 440Ω / □.
Next, as a second acid treatment, the substrate was immersed in a hydrochloric acid solution composed of 20% hydrochloric acid for 10 minutes to increase the resistance value. The sheet resistance value after this second acid treatment was 884Ω / □.

After the acid treatment, the resistance layer 2 was further subjected to a heat treatment at 200 ° C. for 30 minutes. The sheet resistance value of the resistance layer 2 after the heat treatment was 815Ω / □.
Next, an electroless copper process (Shipley Far East CU POSIT) is used on the resistance layer 2 that has been subjected to the acid treatment and the heat treatment, and then is plated with a thickness of 0.3 μm. Plating with a thickness of 10 μm was applied to form a conductor layer 3 (see procedure (1) in step (B-1) and FIG. 1B).

Next, a negative dry film resist 10 (manufactured by Hitachi Chemical Co., Ltd., RY-3315) was laminated on the conductor layer 3. Then, the resist 10 was selectively exposed with ultraviolet rays through a negative pattern (not shown). Here, the negative pattern was designed so that the resist 10 in the resistance element forming region 50 was exposed. The unexposed portion of the resist 10 was removed at a temperature of 30 ° C. using a developer (1% aqueous sodium carbonate solution) (see step (B-1) in step (2) and FIG. 1C).

The conductive layer 3 exposed in the portion where the resist 10 is not formed is removed by etching at 65 ° C. using an iron (III) chloride solution, and then the exposed resistance layer 2 is converted into a copper sulfate-sulfuric acid solution (250 g of copper sulfate). / L, sulfuric acid 5 ml / L) was removed by etching at 90 ° C.
Next, the resist 10 was removed using a stripping solution (5% aqueous sodium hydroxide solution). Thereby, the wiring pattern 4 composed of the conductor layer 3 and the resistance layer 2 ′ was formed in the resistance element formation region 60 (see the procedure (3) in the step (B-1) and FIG. 1D).

A negative dry film resist 12 (manufactured by Hitachi Chemical Co., Ltd., RY-3315) was laminated on the conductor layer 3 and the exposed substrate 1. Next, the resist 12 was selectively exposed with ultraviolet rays through a negative pattern (not shown).
The negative pattern was designed so that the resist 12 was exposed in a region excluding the device electrode isolation region 50. The non-exposed portion of the resist 12 was removed at a temperature of 30 ° C. using a developer (1% aqueous sodium carbonate solution) (see step (C-1) procedure (1) and FIG. 1 (e)).

The conductive layer 3a in the portion 50 where the resist 12 was not formed (that is, the element electrode isolation region 50) was removed by etching using an alkaline etching solution (“A process” manufactured by Meltex Co., Ltd.).
Next, the resist 12 was removed using a stripping solution (5% aqueous sodium hydroxide solution) (see step (C-1) in step (2) and FIG. 1 (f)).
Thus, the resistance element 60 having the resistance layer 2 ′ and the two conductor layers 5 (element electrodes) formed in contact with the resistance layer 2 ′ was manufactured on the substrate 1.
The obtained resistance element 60 exhibited high electrical resistance characteristics even when placed in a heating environment, and was excellent in thermal stability.

(Example 2)
An electroless nickel / phosphorous plating solution having the following composition was prepared.
・ Nickel sulfate hexahydrate 26g / L
・ Α-Alanine (complexing agent) 35.6g / L
・ Sodium hypophosphite monohydrate 30g / L
・ Lead nitrate 1mg / L
・ Ion exchange water remaining

From the nickel / phosphorus thin film having a thickness of 0.5 μm on the substrate 1 having a thickness of 0.4 mm made of bismaleimide triazine resin (BT resin) using the above plating solution under the conditions of a bath temperature of 65 ° C. and a pH of 6.0. A resistance layer 2 was formed on the entire surface (step (see procedure (1a) of A-12 and FIG. 2 (a)).
When the sheet resistance value immediately after electroless plating of the obtained resistance layer 2 was measured, it was 100Ω / □.

A hydrochloric acid aqueous solution having a concentration of 20% by volume was prepared using reagent grade 1 hydrochloric acid. The BT resin substrate 1 having the resistance layer 2 formed on the entire surface was immersed in the aqueous hydrochloric acid solution at room temperature for 3 minutes for acid treatment.
When the sheet resistance value of the resistance layer 2 after the acid treatment was measured, it was 1000Ω / □.
As the second acid treatment after the first acid treatment, the second acid treatment was performed by immersing in a solution of 5 g / L ammonium persulfate for 5 minutes. When the sheet resistance was measured, the sheet resistance further increased and showed 1200Ω / □.
After the acid treatment, the resistance layer 2 was subjected to heat treatment at 200 ° C. for 300 minutes in order to stabilize the plating film. When the sheet resistance value of the resistance layer 2 after the heat treatment was measured, it was 1140Ω / □.

On the resistance layer 2 subjected to the acid treatment and the heat treatment, a negative dry film resist (manufactured by Hitachi Chemical Co., Ltd., RY-3315) was laminated.
Subsequently, the resist was selectively exposed by irradiating ultraviolet rays through a negative pattern (not shown). The negative pattern was designed so that the resist except the desired resistance element formation region 50 was exposed. After the exposure, the unexposed portion of the resist was removed using a developer (1% aqueous sodium carbonate solution) at a temperature of 30 ° C. for 60 seconds. Resist pattern 10 remained in the exposed portion, and resist pattern 10 covering resistance element formation region 50 was obtained. (See step (A-2), procedure (2a) and FIG. 2 (b)).

Part of the resistance layer 2 is etched away at 90 ° C. using a copper sulfate-sulfur resist pattern 10 non-forming acid solution (copper sulfate 250 g / L, sulfuric acid 5 ml / L), and the substrate 1 is placed outside the resistance element formation region 50. Exposed. (See step (A-2), procedure (3a), FIG. 2 (c), and FIG. 2 (c)).
Next, the resist pattern 10 was removed using a stripping solution (5% aqueous sodium hydroxide solution).
Thus, the patterned resistance layer 2 ′ was formed in the resistance element formation region 50 on the substrate 1. (See step (A-2), procedure (4a) and FIG. 2 (d)).

A Pd catalyst (not shown) was applied to the entire surface of the substrate 1 having the patterned resistance layer 2 '(see step (1d) of step (B-2)) and FIG. 4 (a)).
A negative dry film resist (manufactured by Hitachi Chemical Co., Ltd., RY-3315) was laminated thereon. Subsequently, the resist was selectively exposed by irradiating ultraviolet rays through a negative pattern (not shown).
The negative pattern was designed so that the resist on the patterned resistance layer 2a was exposed. After the exposure, the unexposed portion of the resist was removed using a developer (1% aqueous sodium carbonate solution) at a temperature of 30 ° C. for 60 seconds. Resist remained in the exposed portion, and a resist pattern 11 covering the device electrode isolation region 50 was obtained (see step (B-2) in step (2d) and FIG. 4B).

   Plating to a thickness of 0.3 μm using electroless copper plating solution (Meltex Co., Ltd., CU-390) on the portion where the resist pattern 11 is not formed, and further plating to a thickness of 10 μm by electrolytic copper plating Thus, a conductor layer 3 was obtained. The resist pattern 11 was removed using a stripping solution (5% aqueous sodium hydroxide solution) (see step (3d) of step (B-2)) and FIG. 4C).

On the resistance layer 2a and the conductor layer 3, a negative dry film resist (manufactured by Hitachi Chemical Co., Ltd., RY-3315) was laminated. Subsequently, the resist was selectively exposed by irradiating ultraviolet rays through a negative pattern (not shown). The element electrode formation region 50 is set so that the conductor layer 3 is separated into two places in contact with the resistance layer 2a, and the negative pattern is exposed so that the resist on the element electrode formation region and the element electrode separation region 50 is exposed. Designed.
After the exposure, the non-exposed portion of the resist was removed using a developer (1% aqueous sodium carbonate solution) at a temperature of 30 ° C. Thus, the resist pattern 12 was formed so as to protect the resistance layer 2 ′ exposed in the element electrode isolation region 50 and the conductor layer 3 in the element electrode formation region. (Refer to the procedure (4d) of step (B-2)).

A portion of the conductor layer where the resist 12 was not formed was removed by etching at 65 ° C. using an iron (III) chloride solution, and an element electrode was formed from the conductor layer 3 ′ left in the element electrode formation region. Next, the resist 12 was removed using a stripping solution (5% aqueous sodium hydroxide solution) (see step (B-2), step (5d) and FIG. 4 (e)).
As described above, the resistance element 60 having the resistance layer 2 ′ and the two conductor layers 3 ′ (element electrodes) formed in contact with the resistance layer 2 ′ was manufactured on the substrate 1.
The obtained resistance element exhibited high electrical resistance characteristics even when placed in a heating environment, and was excellent in thermal stability.

(Example 3)
This embodiment will be described in detail with reference to FIG.
As shown in FIG. 6 (a), a wiring board made of bismaleimide triazine resin (BT resin) and having a thickness of 0.4 mm is laminated on a substrate 1 having a thickness of 12 μm. In order to form the portion, a resist pattern 10 is formed as shown in FIG. The resist pattern 10 is formed by laminating a dry film resist (manufactured by Hitachi Chemical Co., Ltd., RY-3315) on the entire surface of the copper foil, exposing the pattern forming portion to ultraviolet light, and developing with a 1% sodium carbonate solution. Formed.
After forming the resist pattern 10, the conductor layer was removed by etching at 65 ° C. using an iron (III) chloride solution to form a resistance electrode portion 3 ′ (see FIG. 6C).
After the etching, the resist 10 was removed using a stripping solution (5% aqueous sodium hydroxide solution) (see FIG. 6D).

An electroless nickel / phosphorous plating solution having the following composition was prepared.
・ Nickel sulfate hexahydrate 26g / L
・ Α-Alanine (complexing agent) 35.6g / L
・ Sodium hypophosphite monohydrate 30g / L
・ Lead nitrate 1mg / L
-Ion exchange water Remaining amount Using the above plating solution, a nickel plating film having a thickness of 0.5 μm was formed on the entire surface of the substrate including the electrode 3 ′ under the conditions of a bath temperature of 65 ° C. and a pH of 6.0 (FIG. 6E )reference).
When the sheet resistance value immediately after the electroless plating of the obtained resistance layer 2 was measured, it was 100Ω / □.
Next, an aqueous hydrochloric acid solution having a concentration of 20% by volume was prepared using reagent grade hydrochloric acid. Then, the BT resin substrate 1 on which the resistance layer 22 was formed on the entire surface was immersed in the hydrochloric acid aqueous solution at room temperature for 3 minutes to perform acid treatment.
When the sheet resistance value of the resistance layer 2 after the acid treatment was measured, it was 1000Ω / □.

Next, after the first acid treatment, the second acid treatment was performed by immersing in a solution of 5 g / L of ammonium persulfate for 5 minutes as the second acid treatment.
When the sheet resistance of the resistance layer 2 was measured, the sheet resistance further increased and showed 1200Ω / □.
After the acid treatment, the resistance layer 2 was subjected to a heat treatment at 200 ° C. for 30 minutes in order to stabilize the plating film. When the sheet resistance value of the resistance layer 2 after the heat treatment was measured, it was 1140Ω / □.
In order to pattern the plating film in the resistor region 50 after the heat treatment, a dry film resist (manufactured by Hitachi Chemical Co., Ltd., RY-3315) is laminated on the entire surface of the substrate, and the dry film resist is exposed and developed in the same manner as described above. Then, a resist pattern 12 was formed in the resistor forming region 50 (see FIG. 6F).
The nickel film other than the resist pattern forming portion was removed by etching at 90 ° C. using a copper sulfate-sulfuric acid solution (copper sulfate 250 g / L, sulfuric acid 5 ml / L) (see FIG. 6G).
After the etching, the resist 12 was removed using a stripping solution (5% aqueous sodium hydroxide solution) (see FIG. 6H).
The resistance element 60 having the resistance layer 2 ′ and the two conductor layers 3 ′ (element electrodes) formed in contact with the resistance layer 2 ′ was manufactured on the substrate 1 by the above process.
The obtained resistance element exhibited high electrical resistance characteristics even when placed in a heating environment, and was excellent in thermal stability.

(Comparative Example 1)
A resistance element was formed under the same conditions as in Example 2 except that the second acid treatment in Example 2 was not performed.
When the sheet resistance value of the resistance layer 2 of the resistance layer was measured, it was 1000Ω / □.
However, it is difficult to use it as it is as a resistance element at a value smaller than 1200 Ω / □ which is the sheet resistance value of the desired resistance layer.

  The present invention can be used as a resistance element of a printed circuit board, particularly as a resistance element built in a printed wiring board.

It is explanatory drawing which shows an example of the manufacturing method of the resistive element of this invention. It is explanatory drawing which shows an example of the manufacturing method of the resistive element of this invention. It is explanatory drawing which shows an example of the manufacturing method of the resistive element of this invention. It is explanatory drawing which shows an example of the manufacturing method of the resistive element of this invention. It is explanatory drawing which shows an example of the manufacturing method of the resistive element of this invention. It is explanatory drawing which shows an example of the manufacturing method of the resistive element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2, 2 '... Resistance layer 3, 3' ... Conductor layer 4 ... Wiring pattern 60 ... Resistance element

Claims (9)

The resistive layer of the resistive element comprising the element electrode and the resistive layer,
A resistance film forming step of forming a resistance film on a substrate by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent and a complexing agent;
A first acid treatment step of subjecting the formed resistance film to a first acid treatment;
Next, a second acid treatment step for subjecting the resistance film to a second acid treatment;
A method of manufacturing a resistance element, comprising:   The method of manufacturing a resistance element according to claim 1, further comprising a heat treatment step of performing a heat treatment after the second acid treatment step. A resistance film forming process for forming a resistance film on the entire surface of the substrate by plating, a conductor layer forming process for forming a conductor layer on the formed resistance film, and a wiring pattern forming process for patterning the resistance film and the conductor layer And etching a predetermined portion of the conductor layer, exposing the resistance film under the conductor layer, and forming a resistance layer,
The resistive layer is
A resistance film forming step of forming a resistance film on a substrate by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent and a complexing agent;
A first acid treatment step of subjecting the formed resistance film to a first acid treatment;
Next, a second acid treatment step for subjecting the resistance film to a second acid treatment;
A method of manufacturing a resistance element, comprising:   The method of manufacturing a resistance element according to claim 3, further comprising a heat treatment step of performing a heat treatment after the second acid treatment step.    5. The resistance element manufacturing method according to claim 3, wherein the resistance film formed on the substrate is patterned. On a substrate on which a pre-patterned wiring electrode layer is formed,
A resistance film forming step of forming a resistance film on a substrate by an electroless plating method using an electroless nickel / phosphorous plating solution containing a nickel salt, a reducing agent and a complexing agent;
A first acid treatment step of subjecting the formed resistance film to a first acid treatment;
Next, a second acid treatment step for subjecting the resistance film to a second acid treatment;
A method of manufacturing a resistance element, comprising:   The method of manufacturing a resistance element according to claim 8, further comprising a heat treatment step of performing a heat treatment after the second acid treatment step.   A resistance element comprising a resistance layer formed by the method according to claim 1. A wiring board comprising the resistance element according to claim 8 mounted on a board.

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