JP5635421B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly to a semiconductor device including a soft magnetic thin film having a low coercive force and magnetically converging with the soft magnetic thin film, and a method for manufacturing the same. It relates to a magnetic sensor.

  It is known that a conventional magnetic sensor including a Hall element is provided with a soft magnetic thin film immediately above the Hall element for magnetic convergence (see, for example, Patent Document 1). In such a magnetic sensor, a soft magnetic thin film is arranged on the Hall element, so that the Hall element can detect the magnetic flux leaking from the end of the magnetic focusing plate with high sensitivity due to the magnetic convergence effect. The thin film has a feature that a NiFe alloy thin film is formed by electrolytic plating.

  FIG. 1 is a diagram showing a hysteresis curve of a soft magnetic thin film. Since a soft magnetic thin film that performs magnetic convergence is a magnetic material, the saturation flux density output from the magnetic material with respect to an external magnetic field is as shown in FIG. A simple hysteresis curve is shown. Further, the amount of hysteresis can be defined by the magnitude of the residual magnetic flux density at the intersection of the coercive force that is the intersection of the X axis and the Y axis in the hysteresis curve shown in FIG. However, since the amount of hysteresis varies depending on the direction in which the magnetic field is applied and the magnitude of the external magnetic field, it is necessary to reduce the amount of hysteresis in order to realize more advanced magnetic sensing.

  For example, as disclosed in Patent Document 2, an insulating material is formed on a semiconductor substrate on which one or more Hall elements and a semiconductor circuit are provided, and this insulating material is disclosed. There is a semiconductor device in which a metal conductive layer is formed thereon, and a soft magnetic thin film containing at least boron is formed on the metal conductive layer so as to cover a magnetic sensitive portion of one or more Hall elements.

JP 2003-142752 A JP 2010-159982 A

  As described in Patent Document 2 described above, the soft magnetic thin film is characterized by being formed by electrolytic plating containing a boron-based reducing agent. However, a boron-based reducing agent such as tetramethylamine borane (TMAB) used in Patent Document 2 has an effect of reducing Ni ions and Fe ions in the plating solution, and Ni can be obtained within a few days after adjusting the plating solution. There is a problem that Fe ions precipitate and plating cannot be performed.

  The present invention has been made in view of such problems. The object of the present invention is to add a carbon-based additive that stabilizes a plating solution containing a boron-based reducing agent to the plating solution, and to form a soft magnetic film. By adding carbon derived from additives that stabilize the plating solution into the film, a soft magnetic thin film with a low coercive force can be realized without increasing the amount of boron in the film, and magnetic convergence is achieved with this soft magnetic thin film. An object of the present invention is to provide a semiconductor device and a manufacturing method with high mass productivity.

The present invention has been made to achieve such an object, and the invention according to claim 1 has an iron content of 15 to 15 when the total weight of the formed soft magnetic thin film is 100% by weight. 30 wt%, boron content 0.15 to 0.35 by weight%, 0.4-0.8 wt% of carbon due to pH buffers to stabilize the electrolytic plating solution, the balance nickel A soft magnetic thin film is provided, and magnetic convergence is achieved by the soft magnetic thin film.

According to a second aspect of the present invention, in the first aspect of the present invention, the semiconductor device is a magnetic sensor including a Hall element.

In the invention according to claim 3 , the iron content is 15 to 30% by weight and the boron content is 0.15 to 0.35 when the total weight of the formed soft magnetic thin film is 100% by weight. % Of carbon derived from a pH buffer that stabilizes the electrolytic plating solution, 0.4 to 0.8% by weight, and the manufacturing method of the semiconductor device including the soft magnetic thin film with the balance being nickel, An insulating material is formed on a semiconductor substrate provided with the above Hall elements and a semiconductor circuit, a metal conductive layer is formed on the insulating material, and magnetic sensing of one or more Hall elements is performed on the metal conductive layer. The soft magnetic thin film containing carbon derived from at least boron and a pH buffer that stabilizes the electrolytic plating solution is formed at a position covering the portion.

According to a fourth aspect of the present invention, in the invention of the third aspect , the soft magnetic thin film is electroplated using a plating solution containing a boron reducing agent and a pH buffer that stabilizes the electrolytic plating solution. It is characterized by forming in.

  According to the present invention, a pH buffer comprising a Hall element provided on a semiconductor substrate and a soft magnetic thin film provided on the Hall element, the soft magnetic thin film stabilizing at least boron and an electrolytic plating solution. Therefore, it is possible to provide a semiconductor device that includes a soft magnetic film having a low coercive force and is magnetically converged by the soft magnetic thin film, and a method for manufacturing the same.

  Moreover, when the total weight of the formed soft magnetic thin film is 100% by weight, the iron content is 15 to 30% by weight, the boron content is 0.15 to 0.35% by weight, and the electrolytic plating solution is stabilized. Since this soft magnetic thin film converges magnetically, magnetic sensing can be performed accurately even in a magnetic field environment of several mT, and the absolute value of the unbalanced voltage and its variation are reduced by reducing the amount of hysteresis. There is an effect that can be done.

It is a figure which shows the hysteresis curve of a soft-magnetic thin film. It is a block diagram for describing one embodiment of a semiconductor device according to the present invention. FIG. 4 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2 and a process diagram for forming a semiconductor circuit. FIG. 5 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2 and a process diagram for forming a base conductive layer. FIG. 4 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2 and a process diagram for forming a resist pattern on a base conductive layer. FIG. 4 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2 and a process diagram for forming a soft magnetic thin film. FIG. 4 is a process diagram for explaining the method of manufacturing the semiconductor device shown in FIG. 2 and a process diagram for removing a resist. FIG. 4 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2 and a process diagram for removing a base conductive layer. It is a figure which shows the relationship between trisodium citrate addition amount and coercive force in Example 1 and Comparative Example 1. It is a figure which shows the relationship between the trisodium citrate addition amount and the residual magnetic flux density in Example 1 and Comparative Example 1. It is a figure which shows the relationship between the trisodium citrate addition amount and the boron content in a soft-magnetic thin film in Example 1 and Comparative Example 1. It is a figure which shows the relationship between the amount of trisodium citrate addition in Example 1 and the comparative example 1, and the carbon content in a soft-magnetic thin film. It is a figure which shows the relationship between the boron content in the soft magnetic thin film of patent document 2 and Example 1, and a coercive force. It is a figure which shows the analysis result implemented in order to identify the presence of a citric acid in TOF-SIMS of the soft-magnetic thin film in Example 1. FIG. It is a figure which shows the relationship between trisodium citrate addition amount and coercive force in Example 1 and Comparative Example 2.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 is a block diagram for explaining an embodiment of a semiconductor device according to the present invention. In the figure, reference numeral 1 denotes a semiconductor substrate, 2 denotes a Hall element, 3 denotes an external connection terminal pad, 4 denotes an organic insulating film, 5 Indicates a base conductive layer (metal conductive film), and 6 indicates a soft magnetic thin film.

  The semiconductor device of the present invention is a semiconductor device having a small amount of hysteresis by providing a soft magnetic thin film containing a predetermined amount of boron on a Hall element compared to a semiconductor device that has been magnetically converged by a conventional magnetic material. It is obtained. The semiconductor device of the present invention includes a magnetic sensor provided with a Hall element.

  The semiconductor device of the present invention includes a Hall element 2 provided on a semiconductor substrate 1 and a soft magnetic thin film 6 provided on the Hall element 1, and the soft magnetic thin film 6 contains at least boron. . In addition, an organic insulating film 4 provided on the semiconductor substrate 1 and on the Hall element 2 and a metal conductive layer 5 provided between the organic insulating film 4 and the soft magnetic thin film 6 are provided. A thin film 6 is disposed on the metal conductive layer 5 so as to cover at least one magnetic sensing portion of the Hall element 2.

  That is, the semiconductor device of the present invention is characterized in that the semiconductor substrate 1 is provided with the Hall element 2, the organic insulating film 4 is provided on the semiconductor substrate 1, and the underlying conductive layer 5 and the soft magnetic thin film 6 are provided immediately above the Hall element 1. Is provided.

  The soft magnetic thin film 6 has an iron content of 15 to 30% by weight and a boron content of 0.15 to 0.35% by weight when the total weight of the formed soft magnetic thin film is 100% by weight. The semiconductor device is characterized by 0.4 to 0.8% by weight of carbon resulting from a pH buffer that stabilizes the semiconductor, and the balance is nickel, and the coercive force can be reduced by controlling the thickness to 4 to 40 μm. It becomes possible. Incidentally, the crystallite size in the soft magnetic thin film at that time is 5 to 10 nm, and the crystal orientation degree of NiFe (111) is 70 to 100%. The soft magnetic thin film has a coercive force of 0.1 to 15 A / m and a residual magnetic flux density of 0.05 to 0.6 T.

  3 to 8 are process diagrams for explaining a method of manufacturing the semiconductor device shown in FIG. In the method of manufacturing a semiconductor device according to the present invention, an organic insulating film 4 is formed on a semiconductor substrate provided with one or more Hall elements and a semiconductor circuit, and a metal conductive layer 5 is formed on the organic insulating film 4. The soft magnetic thin film 6 containing at least boron is formed on the metal conductive layer 5 and at a position covering the magnetically sensitive portion of one or more Hall elements. The soft magnetic thin film 6 is formed by electrolytic plating using a plating solution containing a boron reducing agent.

Below, the manufacturing method of the semiconductor device which concerns on this invention is demonstrated along process order.
FIG. 3 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2, and is a process diagram for forming a semiconductor circuit. First, as shown in FIG. 3, at least one Hall element 2 for magnetic sensing is disposed on the semiconductor substrate 1, and the external connection terminal pad 3 is opened for electrical connection with the external electrode. An organic insulating film 4 is formed. The semiconductor substrate 1 may be either a silicon wafer or a GaAs substrate, and the Hall element 2 is preferably a semiconductor on which a signal processing circuit such as Si is formed or a compound semiconductor such as InSb, InAs, or GaAs. Alternatively, an impurity doped with Sn, Zn, Si, or the like may be used. Further, as the material of the external connection terminal pad 3, an AL-based material or an Au-based material is generally used. The organic insulating film 4 is preferably made of an organic material such as polyimide, polybenzoxazole, benzocyclobutene, or photosensitive silicone.

  FIG. 4 is a process diagram for explaining the method of manufacturing the semiconductor device shown in FIG. 2, and is a process diagram for forming a base conductive layer. As shown in FIG. 4, the base conductive layer 5 is disposed on the organic insulating film 4 and the external connection terminal pads 3. A laminated film is used as the base energizing layer 5, a Ti-based material such as Ti or TiW as the first layer, a Cu-based material, an AL material, or a NiFe-based material as the second layer by vacuum evaporation, sputtering, It is formed by electrolytic / electroless plating. The Ti-based material desirably has a thickness of at least 0.1 μm or more as a diffusion barrier layer of the Al-based material of the external connection terminal pad 3 and the Cu-based material of the ground conductive layer 5.

  Further, the second layer, Cu-based material, AL material, and NiFe-based material are preferably thicker in order to lower the electrical resistance, and preferably 0.1 to 10 μm. Cu is oriented in the crystal orientation of (111). In order to reduce the mismatch of the crystal orientation of the soft magnetic thin film 6, it is better to use Cu having the crystal orientation of (111) as a layer for depositing the soft magnetic thin film 6.

  FIG. 5 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2, and is a process diagram for forming a resist pattern on the underlying conductive layer. Next, as shown in FIG. 5, a resist 7 is formed on the underlying conductive layer 5 in order to form a pattern of the soft magnetic thin film 6, and exposure and development are performed to form a resist gap 7a. As the resist material, either a positive resist or a negative resist may be used, but in general, a naphthoquinone diazo type positive resist capable of satisfying both acid resistance and releasability during plating is desirable. The resist 7 can be formed to a maximum thickness of 50 μm by using a phenol novolac positive resist. Further, since the resist 7 needs to be thicker than the soft magnetic thin film 6, it is preferably 5 to 50 μm.

  FIG. 6 is a process diagram for explaining a method of manufacturing the semiconductor device shown in FIG. 2, and is a process diagram for forming a soft magnetic thin film. Next, as shown in FIG. 6, a soft magnetic thin film 6 made of boron, nickel and iron is formed in the resist gap 7a by electrolytic plating. The soft magnetic thin film 6 is preferably thicker in order to achieve the magnetic convergence effect. However, if the film is thicker than the resist 7, the soft magnetic thin film 6 does not grow vertically but grows in a mushroom shape. Therefore, the film thickness of the soft magnetic thin film 6 is desirably smaller than the film thickness of the resist 7, and is particularly preferably in the range of 4 to 40 μm.

  In order to perform electroplating, the cathode on which the wafer on which the underlying conductive layer 5 is formed is used as a cathode, and an anode is used by using a soluble metal plate such as nickel or iron or an insoluble metal plate such as platinum as an anode. A soft magnetic thin film can be formed on the portion to be plated. As the plating solution, nickel sulfate, nickel chloride, iron sulfate, boric acid, saccharin, sodium chloride and boron-based reducing agents such as tetramethylamine borane (TMAB) and dimethylamine borane (DMAB) were used. Boron was co-deposited in the soft magnetic thin film by adding TMAB or DMAB to the plating solution.

  In addition, when electrolytic plating is performed using this plating solution, the deposition potential of the plating film changes depending on the temperature of the plating solution, so the temperature of the plating solution must be heated and cooled using a thermocouple, heater, or chiller. is there. The temperature of the plating solution varies greatly depending on plating conditions such as current density and pH, but is preferably 20 to 60 ° C. Also, it is necessary to optimize the cathode current density and pH during plating. The cathode current density is preferably 1 to 70 mA / cm 2. Further, when the pH is lowered to 2.0 or less, the amount of hydrogen generated increases, and the plating thickness becomes thin even during the same plating time. Therefore, the pH is preferably 2.0 or more, and when the pH is 7.0 or more, TMAB is reduced to a reducing agent. Since the electroless plating reaction occurs and Ni and Fe are precipitated, the pH is preferably between 2.0 and 7.0.

  Furthermore, boron reducing agents such as TMAB release OH- ions upon hydrolysis, and the reaction is more pronounced on the alkali side. Therefore, the decomposition of TMAB is further promoted by the decomposition of TMAB, so that precipitation due to electroless reaction is formed in Ni and Fe in about one day, and plating cannot be performed. In order to prevent the precipitation reaction, it is more preferable to add a pH buffering agent in order to suppress the hydrolysis reaction of TMAB. Examples of the pH buffering agent include carboxylic acids such as formic acid, oxalic acid, malonic acid, succinic acid, tartaric acid, citric acid, L-ascorbic acid, or other organic acids having a pH buffering effect. Not limited. At this time, when a pH buffer is added, the relationship between the coercive force and the pH changes depending on the presence or absence of the buffer. Further, the soft magnetic thin film contains carbon resulting from the organic pH buffer.

  FIG. 7 is a process diagram for explaining the method of manufacturing the semiconductor device shown in FIG. 2, and is a process diagram for removing the resist. Next, as shown in FIG. 7, the resist 7 is removed. As a result, the soft magnetic thin film 6 remains on the underlayer conductive layer 5.

  FIG. 8 is a process diagram for explaining the method of manufacturing the semiconductor device shown in FIG. 2, and is a process diagram for removing the underlying conductive layer. Finally, as shown in FIG. 8, the base conductive layer 5 that is no longer needed is removed by a dry etching method or a wet etching method using the soft magnetic thin film 6 as a mask. At that time, it is important to prevent the magnetic material from being etched at the same time.

  As an evaluation method for soft magnetic thin films formed by electroplating, boron content is calculated using inductively coupled plasma emission spectrometry (ICP), and NiFe orientation and crystallite size are calculated using X-ray diffraction. did. Further, the magnetic characteristics were measured using a direct current magnetization measuring device.

  The amount of boron and the amount of carbon in the soft magnetic thin film 6 were measured using inductively coupled plasma emission spectrometry (ICP). A soft magnetic thin film was put into hydrochloric acid (1 + 1) and nitric acid, heated on a heater, the soft magnetic film and the base conductive layer were dissolved, the emission intensity was measured by ICP, and a standard sample with a known concentration was dissolved. The content of each element was calculated from the calibration curve.

  The crystal orientation of the soft magnetic thin film was measured by an X-ray diffraction method at 2θ / ω in the out of plane direction using Cu Kα ray as an excitation line, and (111) and (200 ) To calculate the integrated value of the peak intensities of (111) and (111) by evaluating how much of the peak integrated value of (111) is relative to the sum of the peak integrated values of (111) and (200). The degree (%) was evaluated. The crystallite size was calculated using the Scherrer equation from the half-value width of the (111) peak of the alloy of Ni and Fe obtained from X-ray diffraction.

  Magnetic characteristic measurement is performed by setting a semiconductor device chip on which a soft magnetic thin film is formed on a sample table and drawing a magnetization curve generated when the sample is vibrated while generating a magnetic field by an electromagnet. Density was calculated.

Hereinafter, each example will be described in detail based on the embodiment of the present invention. Note that the present invention is not limited to these examples.
[Example 1 and Comparative Example 1]
First, Example 1 and Comparative Example 1 of the soft magnetic thin film according to the semiconductor device of the present invention will be described.
Using a silicon substrate as the semiconductor substrate 1, an IC in which a signal processing circuit and a Hall element are combined is formed. The external connection terminal pad 3 of the IC is formed using Al, and the Al pad is opened to form polyimide with a thickness of 5 μm.

  On top of that, the base energizing layer 5 was formed by sputtering using Ti of 1500 mm and Cu of 6000 mm, and using a 20 μm positive rest, a 300 μm circular opening was opened by exposure and development processing for each chip unit of the IC.

  The semiconductor substrate 1 in which the resist was opened was set as a cathode in a plating holder, and a nickel plate having a purity of 4N was used as an anode. The substrate was immersed in electrolytic plating and energized to perform electroplating. As a plating solution for electrolysis, added to a plating solution containing 5 g / L of iron sulfate heptahydrate, 35 g / L of nickel sulfate hexahydrate, and 85 g / L of nickel chloride hexahydrate Boric acid and sodium chloride 25g / L, sodium saccharinate 1.5g / L and TMAB 12g / L were added as agents, and finally the pH of the plating solution was adjusted with p3.6 using 1N hydrochloric acid. The cathode current density during plating was fixed at 6 mA / cm 2 and the solution temperature was fixed at 30 ° C., and in Example 1, trisodium citrate was added as a pH buffering agent in 2.5, 5.0, 10. 0, 20.0, 30.0 g / L was added and electroplating was performed.

  Further, as Comparative Example 1, without adding trisodium citrate, the plating time was adjusted so that the thickness of the soft magnetic thin film was 13 μm as in the example, and electrolytic plating was performed.

  Next, the resist was removed with an organic solvent made of NMP, and Ti and Cu were removed by a wet etching method to produce a semiconductor device of the present invention.

  The soft magnetic thin film of the prepared semiconductor device was dissolved in hydrochloric acid (1 + 1) and nitric acid, and ICP measurement was performed to identify the boron content in the soft magnetic thin film. In addition, with the soft magnetic thin film attached to the semiconductor device, X-ray diffraction is performed, the crystal orientation and crystal size, and the magnetic characteristics are evaluated with a DC magnetometer, and the amount of TMAB added is changed to change the soft magnetism. The effect of magnetic properties and crystal structure by changing the boron content in the thin film was experimentally confirmed.

  FIG. 9 is a diagram showing the relationship between the amount of trisodium citrate added in the soft magnetic thin film and the coercive force in Example 1 and Comparative Example 1, and FIG. 10 shows the addition of trisodium citrate in Example 1 and Comparative Example 1. 11 is a diagram showing the relationship between the amount and the residual magnetic flux density. FIG. 11 is a diagram showing the relationship between the trisodium citrate addition amount and the boron content in the soft magnetic thin film 6 in Example 1 and Comparative Example 1. FIG. FIG. 5 is a graph showing the relationship between the amount of citric acid added in Example 1 and Comparative Example 1 and the carbon content in the soft magnetic thin film 6.

  As shown in FIG. 9, even when the same amount of TMAB was added, the coercive force was about 5 A / m when the amount of trisodium citrate in the plating solution was 2.5 to 20 g / L. When 30 g / L is added, the coercive force increases to 30 A / m, so it is considered not preferable to add 20 g / L or more of trisodium citrate. FIG. 10 shows the relationship between the amount of citric acid added and the residual magnetic flux density in the soft magnetic film. It was found that the residual magnetic flux density increased to about 0.5 T when trisodium citrate was added at 20 g / L or more. Further, in FIG. 11, the relationship between the added amount of trisodium citrate and the boron content in the soft magnetic thin film 6 was examined, and in FIG. 12, the relationship between the added amount of trisodium citrate and the carbon content was investigated. In the system containing no citric acid in Comparative Example 1, the boron content is 0.50% by weight and the carbon content is 0.3% by weight, whereas the citric acid is 2.5 g / L to 10 g / L. By adding, it was confirmed that the boron content decreased by about 0.2% by weight, whereas the carbon content increased by 0.2% by weight.

  FIG. 13 is a diagram showing the relationship between the boron content and the coercive force in the soft magnetic thin films of Patent Document 2 and Example 1. As shown in FIG. 13, comparing the relationship between the boron content and the coercive force of Patent Document 2, it can be seen that a low coercive force can be realized with a smaller amount of boron compared to Patent Document 2, and even with the same boron content, TMAB can be realized. It was confirmed experimentally that the coercive force can be made smaller than that of the single substance. Similarly to Patent Document 2, when the crystal structure of the soft magnetic thin film to which 5.0 g / L of trisodium citrate was added was evaluated, the degree of (111) orientation (crystal orientation) was 73%, and the crystallite It was confirmed that the size was as small as 8 nm.

  Furthermore, in order to confirm the presence of citric acid, in order to identify the organic acid in the soft magnetic film as the amount of C, in addition to identify that the citric acid added by carbon quantified by analysis is the source, Fragments were analyzed by TOF-SIMS. The result is shown in FIG.

  FIG. 14 is a diagram showing the results of analysis performed to identify the presence of citric acid in TOF-SIMS of the soft magnetic thin film in Example 1. Peaks of citric acid fragment ion (C3H3O3) m / z = 87 and carboxylic acid-derived m / z = 45 were detected, and no carboxylic acid source other than organic acid was supplied in the plating solution. Thus, the presence of citrate molecules in the soft magnetic thin film could be identified.

  Moreover, the stability of the plating solution was improved by adding trisodium citrate to the plating solution. As shown in Table 1, in the plating solution in which only TMAB of Comparative Example 1 was added, the precipitate and coercive force of Fe significantly increased to 55 A / m in the plating solution 2 days after the preparation of the plating solution, whereas Example 1 It was confirmed experimentally that the coercive force did not increase even in 30 days in the system added with 2.5 g / L and 5.0 g / L of citric acid.

  Table 1 is a table showing the transition of the coercive force depending on the number of days elapsed from the preparation of the plating solutions of Example 1 and Comparative Example 1.

[Comparative Example 2]
From the result of Example 1, since it was confirmed that citric acid also has a coercive force reducing effect, it is basically the same as the production method of Example 1 above, but only citric acid is added without adding TMAB. The added plating solution was prepared and plated. The result is shown in FIG.

  FIG. 15 is a graph showing the relationship between the trisodium citrate addition amount and the coercive force in Example 1 and Comparative Example 2. Similar to Example 1, even when the citric acid concentration was varied, the coercive force was 30 to 50 A / m, and it has been confirmed that trisodium citrate alone has no effect of reducing the coercive force like TMAB. It has been experimentally confirmed that trisodium citrate can exhibit the effect of reducing the coercive force by coexisting TMAB and trisodium citrate.

  From these results, in order to reduce the liquid even after long-term use and to be excellent in mass productivity and to reduce the coercive force to 15 A / m or less, a boron-based reducing agent such as TMAB and a pH such as trisodium citrate are used. It was confirmed experimentally that it is very important to coexist the buffer.

[Example 2]
GaAs was used as the semiconductor substrate, and a compound semiconductor made of InAs was used as the Hall element. As the external electrode, a laminated structure of Ti and Au was formed by vapor deposition. A polyimide pattern is formed directly on the Hall element to a thickness of 5 μm, and a resist pattern is formed on the base energizing layer formed by sputtering with Ti of 1500 mm and Cu of 6000 mm. A soft magnetic film having a thickness of 13 μm was formed using a plating solution containing 12 g / L of TMAB and 5.0 g / L of trisodium citrate. Further, as Comparative Example 2, a soft magnetic film having a thickness of 13 μm was formed using a plating solution to which TMAB was not added. The hysteresis width of the Hall electromotive force when 3 V was applied was evaluated while changing the magnetic field from +40 mT → −40 mT → + 40 mT on the element produced by resist stripping and etching.

  The hysteresis width is the difference between the amount of magnetic field where the Hall output becomes zero when the magnetic field is changed from +40 mT to −40 mT, and the magnetic field amount when the Hall output becomes zero when the magnetic field is changed from −40 mT to +40 mT. When defined, it was confirmed that the hysteresis width was as small as 0.01 mT. In fact, even in semiconductor devices, it is expected that magnetic sensing with a small amount of hysteresis can be realized and a manufacturing method with excellent mass productivity can be provided by appropriately managing the amount of boron and the amount of carbon in the soft magnetic thin film 6. I can do it.

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Hall element 3 External connection terminal pad 4 Organic insulating film 5 Ground conductive layer (metal conductive film)
6 Soft magnetic thin film 7 Resist 7a Resist gap

Claims (4)

  When the total weight of the formed soft magnetic thin film is 100% by weight, the iron content is 15 to 30% by weight, the boron content is 0.15 to 0.35% by weight, and the pH buffer stabilizes the electrolytic plating solution. A semiconductor device comprising: the soft magnetic thin film having 0.4 to 0.8% by weight of carbon derived from an agent and the balance being nickel, and magnetically converges with the soft magnetic thin film. The semiconductor device according to claim 1, wherein the semiconductor device is a magnetic sensor including a Hall element. When the total weight of the formed soft magnetic thin film is 100% by weight, the iron content is 15 to 30% by weight, the boron content is 0.15 to 0.35% by weight, and the pH buffer stabilizes the electrolytic plating solution. A method of manufacturing a semiconductor device comprising the soft magnetic thin film, wherein carbon caused by the agent is 0.4 to 0.8% by weight and the balance is nickel,
An insulating material is formed on a semiconductor substrate provided with one or more Hall elements and a semiconductor circuit, a metal conductive layer is formed on the insulating material, and one or more Hall elements are formed on the metal conductive layer. A method of manufacturing a semiconductor device, comprising: forming the soft magnetic thin film containing at least boron and carbon derived from a pH buffer that stabilizes an electrolytic plating solution at a position covering a magnetic sensitive portion. 4. The method of manufacturing a semiconductor device according to claim 3 , wherein the soft magnetic thin film is formed by electrolytic plating using a plating solution containing a boron reducing agent and a pH buffer that stabilizes the electrolytic plating solution.

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