JPH0677072A - Manufacture of planar type magnetic element - Google Patents

Abstract

PURPOSE:To realize a method of manufacturing a planar-type magnetic element which is of high performance of provided with coil conductors thick enough and having a space of small width between them. CONSTITUTION:There are provided a first process where an insulating film 4 is formed on a magnetic film 3 to form a space between coil conductors, a second process where the insulating film 4 is patterned into a space between the coil conductors, a third process where the surface of the patterned insulating film 4 is so modified as to enable a conductor film to grow selectively, a fifth process where a conductor film 5 is selectively formed in the gap of the patterned insulating film 4 for the formation of a coil conductor, a sixth process where an insulating film 6 is formed on all the surfaces, and a seventh process where a magnetic film 7 is formed on the insulating film 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a planar magnetic element such as a planar inductor or a planar transformer.

[0002]

2. Description of the Related Art In recent years, miniaturization of various electronic devices has been actively promoted with the progress of integrated circuit technology typified by LSI. However, the tendency of the volume ratio of the power supply section in the entire device to increase has become remarkable. This is because the miniaturization and integration of magnetic components such as inductors and transformers, which are essential for the power supply, are significantly delayed compared to other components.

Recently, in order to reduce the size of magnetic elements such as inductances and transformers, it has been proposed to make these magnetic elements flat, and studies are being made to improve their performance. Conventionally known planar inductors have a structure in which both sides of a spiral planar coil are sandwiched between insulating layers, and these both sides are sandwiched between magnetic materials. Similarly, as the plane transformer, a spiral side flat coil on the primary side and a spiral side flat coil on the secondary side are formed through an insulating layer, both sides of which are sandwiched by insulating layers, and both sides are made of a magnetic material. A sandwiched structure is known. The spiral plane coil may be composed of one layer of spiral coil conductor, or may be one in which two layers of spiral coil conductor are formed on both surfaces of an insulating layer and connected so that the generated magnetic fields are in the same direction. Good. For these planar magnetic elements, for example, "High-Frequency" is used.
of a Planar-Type Microtr
transformer and Its Applica
tion to Multilayered Switch
ching Regulators ”; K. Yamas
awa et al. , IEEE Trans. Ma
g. Vol. 26, No. 3, May 1990, p
p. 1204-1209. However, the conventional planar type magnetic element has a drawback that a loss for operation is large.

Further, in order to miniaturize the planar type magnetic element, manufacturing using a thin film process has been studied. The coil patterning is an important factor among them. The spiral coil can have a large inductance and, as a result, can have a high quality factor Q, and thus has an advantageous shape in consideration of device formation.

In order to obtain a spiral coil having a high quality factor, it is preferable to set some parameters to optimum values when manufacturing the coil. Important parameters are (1) coil film thickness, (2) coil line width / space width, (3) spiral coil external dimensions, (4)
Typical examples are the external dimensions of the planar inductor. Of these, except for (2), the optimum value can be almost determined according to the operating frequency of the coil. Therefore, the optimal relationship between the line width (δ) of the coil and the space width (s) of (2) will be described below.

FIGS. 7 (a) and 7 (b) respectively show a predetermined inductance (in a plane) in which the horizontal width represents the line width (δ) of the spiral coil forming the planar inductor and the vertical axis represents the space (s) width. It is a figure which shows the conditions which can obtain L) and coil resistance (R). (A) in the figure is the product of magnetic permeability of magnetic material and thickness of magnetic material μ _s · t = 100
0 μm, (b) is the case of μ _s · t = 5000 μm. Further, in any case, the dimension w of one side of the outer shape of the magnetic body is 5 mm, and the dimension of one side of the spiral coil shape is a _o =
5 mm (equal to the outer dimension w of the magnetic body), the dimension _ai of the inner side of the spiral coil a _i = 0.2 mm, the number of turns of the spiral coil N = 10, the thickness of the coil conductor t _c = 10
μm, the gap between magnetic bodies g = 12 μm. here,
The practical line / space (δ / s) range of the coil is Nδ + (N−1) s ≦ (w−a _i ) / 2. Under the above conditions, 10δ + 9s ≦ 2400 μm.

As is apparent from FIG. 7, the inductance L changes variously depending on the values of δ and s. On the other hand, the coil resistance R decreases as s decreases and δ increases. That is, the influence of δ and s is more remarkable in R than in L.
Since the Q value of the inductor is proportional to L / R, in order to increase it, δ and s are determined in the vicinity of s → 0 (or δ / p → 1, where p is the coil pitch and p = δ + s). Is important.

FIG. 8 shows the dependence of L / R on δ / p. The vertical axis is L / R normalized by L / R (δ / p → 1), that is, the value of L / R when δ / p approaches 1. Further, in this figure, the outer dimensions of the magnetic body: w = 1 to 5 mm, the inner dimensions of the spiral coil: a _i = 0.2 mm, the outer dimensions of the spiral coil: a _o = 0.9 w, and the transmittance and thickness of the magnetic body. Product of: μ _s · t = 10 ³ -10
^Four μm

The region containing all the values obtained by calculation for the various cases of is indicated by the shaded region. L / R is maximum when δ / p is 1, and decreases when δ / p becomes smaller. From this, as in the conclusion of FIG. 7, in order to obtain a planar inductor with a high Q value, δ / p = 1
It is important to determine the coil line width (δ) / space width (s) in the vicinity.

When manufacturing such a planar inductor, the coil pattern is manufactured by applying a semiconductor manufacturing process and using a thin film forming technique and various lithographic techniques. Factors that determine the processing limit in these techniques include an exposure method, a resist material, and an etching method. However, as long as the photolithography technique is used, the wavelength of the light source used for exposure is the largest factor, and the minimum line width obtained by the g-line or i-line currently used is about 0.5 μm. On the other hand, it is predicted that resolution of 0.1 μm or less will be obtained by exposure with an excimer laser or SOR light in the future. Further, although the productivity is deteriorated, the line width of about 0.05 μm can be obtained by the electron beam linear exposure.

On the other hand, a coil conductor forming a planar inductor
Body thickness is determined at least by the frequency band used
It is necessary to set the skin depth approximately. This
Kindeps δ is generally represented by the following equation. δ = (ρ / πμf)^1/2  (Where ρ is the specific resistance, μ is the relative permeability, and f is the frequency.
It )

As described above, the skin depth and the specific resistance of the coil conductor have a positive correlation. FIG. 9 shows the relationship between the specific resistance of the coil conductor and the skin depth, using the frequency as a parameter. For example, when Al having a specific resistance of 2.7 μΩ · cm is used as the coil conductor material, the thickness of the coil conductor is about 10 μ in the operating frequency band 10 to 100 MHz.
It will be about m. When the thickness of the coil conductor is set to about 10 μm and the width of the space between the coil conductors is narrowed in order to obtain a high Q value close to the above theoretical value, the aspect ratio of the groove in the space portion becomes 10 to 100. turn into.

Currently, the technique for etching a conductor film with such a high aspect ratio is a chemical etching technique (C
Both DE and RIE) and physical etching techniques (ion beam etching, etc.) are difficult.
Therefore, in the actual prototype example, the aspect ratio of the inter-conductor space cannot be increased, and a plane inductor of a practical level having a high Q value has not been manufactured. Also, it becomes difficult to fill the groove in the space between the coil conductors formed by etching with the insulating film as the aspect ratio increases. For example, in an ordinary thin film forming process, when the aspect ratio of the inter-conductor space exceeds 2, it becomes impossible to fill the inter-coil conductor space.

On the other hand, if Cu having a specific resistance of 1.7 μΩ · cm can be used as the coil conductor material, the requirement for the aspect ratio can be reduced. However, Cu cannot be selectively etched by applying photolithography. If a coil conductor made of Cu is formed by a conventional electroplating method, only a very low aspect ratio is obtained, and a high Q value is obtained.
A practical level planar inductor having a value cannot be manufactured.

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to manufacture a high performance planar magnetic element having a small width between coil conductors and a coil conductor having a sufficient thickness in a very simple process. To provide a method.

[0016]

According to the first aspect of the present invention, there is provided a method of manufacturing a flat magnetic element, comprising: a step of forming an insulating film forming a space between coil conductors on a magnetic film; The step of patterning the shape of the space between conductors, the step of surface-modifying the insulating film pattern so that the conductive film can be selectively grown, and the step of selectively filling the gap between the insulating film patterns with the conductive film to form a coil The method is characterized by including a step of forming a conductor, a step of forming an insulating film on the entire surface, and a step of forming a magnetic film on the insulating film.

In this method, as a method of modifying the surface of the insulating film pattern forming the space between the coil conductors so that the conductive film can selectively grow, the same or similar material as the coil conductor is formed only on the surface of the recess. A method of forming a thin film, a method of forming a polycrystalline silicon film by reducing the surface of the SiO ₂ film using a hydrogen ion beam, and the like can be given.

In this method, the insulating film is patterned into a space between coil conductors to form an insulating film pattern having a high aspect ratio, and then the insulating film pattern is surface-modified so that the conductive film can be selectively grown. Therefore, the conductor film can be easily filled and the coil conductor can be formed. Therefore, it is possible to manufacture a high-performance planar magnetic element having a small width between coil conductors and a coil conductor having a sufficient thickness.

In the method for manufacturing a planar magnetic element according to the second aspect of the present invention, a step of forming a thin conductor film pattern corresponding to the coil conductor pattern on the magnetic film via an insulating film and a space between the coil conductors over the entire surface. A step of forming an insulating film to be formed, a step of patterning the insulating film into a shape of a space between coil conductors to expose the conductive film pattern, and an electroplating method on the conductive film having a narrow gap of the insulating film pattern. A step of filling a conductor film to form a coil conductor,
The method is characterized by including a step of forming an insulating film on the entire surface and a step of forming a magnetic film on the insulating film.

In this method, the insulating film is etched to form an insulating film pattern having a high aspect ratio, and then the electroplating method is used to easily fill the thin conductive film pattern with the conductive film to form the coil conductor. . Also, since a coil conductor made of a material having a low specific resistance can be formed,
The coil resistance can be reduced. Therefore, it is possible to manufacture a high-performance planar magnetic element having a small width between coil conductors and a coil conductor having a sufficient thickness. On the other hand, since the coil resistance can be reduced, the requirement for a high aspect ratio can be reduced.

In the method of manufacturing a planar magnetic element according to the third aspect of the present invention, a step of forming an insulating film forming a space between coil conductors on a magnetic film and patterning this insulating film into a shape of the space between coil conductors. A step of forming a film (for example, a resist) soluble in an organic solvent on the insulating film pattern, and forming a conductive film on the entire surface by physical vapor deposition to form a conductive film in the gap between the insulating film patterns. The step of filling to form a coil conductor, the step of dissolving a film soluble in an organic solvent and removing the conductive film formed thereon, the step of forming an insulating film on the entire surface, and this insulating film And a step of forming a magnetic film thereon.

In this method, after the insulating film is etched to form an insulating film pattern having a high aspect ratio, a physical vapor deposition method (sputtering method or vapor deposition method) is used, and an etchback method is used in combination. The membrane can be easily filled to form a coil conductor. Moreover, since the coil conductor made of a material having a low specific resistance can be formed, the coil resistance can be reduced. Therefore, it is possible to manufacture a high-performance planar magnetic element having a small width between coil conductors and a coil conductor having a sufficient thickness. On the other hand, since the coil resistance can be reduced, the requirement for a high aspect ratio can be reduced.

A method of manufacturing a planar magnetic element according to a fourth aspect of the present invention comprises a step of forming a first conductor film on a magnetic film via an insulating film, and a step of selectively etching the first conductor film. A step of forming a first conductor film pattern in a region corresponding to the vicinity of the space between coil conductors in a coil conductor region to be formed, and a step of filling an insulating film in a gap between the first conductor film patterns. A step of selectively removing an insulating film filled in a region of the coil conductor region corresponding to the central portion of the coil conductor, and an electric field plating method in a gap of the first conductor film pattern in the region where the insulating film is removed. A step of filling a second conductor film to form a coil conductor composed of the first and second conductor films, a step of forming an insulating film on the entire surface, and a step of forming a magnetic film on the insulating film. It is characterized by having .

In this method, the coil conductor is composed of the first and second conductor films, and the specific resistance thereof is determined by the cross-sectional area ratio of the two. Therefore, by using the second conductor film having a small specific resistance, the coil resistance can be made smaller than that of the coil conductor formed of only the first conductor film. On the other hand, since the coil resistance can be reduced, the requirement for a high aspect ratio can be reduced. Hereinafter, the method of the present invention will be described in more detail. The flat magnetic element of the present invention is formed on a predetermined substrate. The substrate is not particularly limited, and Si,
A semiconductor substrate such as GaAs or an insulating substrate is used.

The magnetic film is formed on the surface of the semiconductor substrate via an insulating film or directly on the insulating substrate. The magnetic film is preferably formed of various magnetic alloys by a method such as sputtering. A buffer layer may be formed between them.

The insulating film forming the space between the coil conductors preferably has a small relative permittivity in order to reduce the line capacitance between the coil conductors. As the material of the insulating film,
Examples thereof include various oxides, nitrides, fluorides, hydrocarbon-based polymer compounds and polysilanes. Typical materials are
SiO ₂ , Si _x N _y , CaF ₂ , polyimide and the like. The insulating film needs to be thick enough to insulate the coil conductor from the magnetic film. The thickness differs depending on the insulating film material. For example, when SiO ₂ is used, a thickness of about 1 μm is suitable when the operating voltage is 20V. Examples of the method for forming the insulating film include a vapor deposition method such as a CVD method and a sputtering method, and a method of applying an insulating material using a spinner and thermally curing it.

A material having a low specific resistance is preferably used as the conductor film forming the coil conductor. In particular,
Al, Al alloy, Cu, Cu alloy, Ag, Ag alloy, P
Examples thereof include, but are not limited to, d, Pd alloy, Pt, and Pt alloy. However, when the step of selectively etching the conductor film is applied, a material such as Al that can be selectively etched is used. The crystal structure of the coil conductor may be polycrystalline or single crystal. The film thickness of the conductor film is determined in consideration of at least the skin depth determined by the frequency band in which the magnetic element is used and the specific resistance of the coil conductor material. Further, as the size of the magnetic element is reduced, the density of current flowing through the conductor increases, and the amount of heat generated from the element becomes very large. Therefore, resistance to disconnection due to electromigration or thermomigration of the coil conductor itself and resistance to disconnection due to stress migration generated by internal stress applied to the coil conductor are very important factors. Therefore, as the coil conductor thin film, it is preferable to use a highly oriented film, and it is more preferable to use a single crystal or a thin film having some defects but close to a single crystal. Examples of the method for forming the conductor film include a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, various sputtering methods, various CVD methods, and various plating methods.

In order to pattern the insulating film or the conductive film into a coil shape, it is preferable to use an etching method having large anisotropy. Specifically, a chemical dry etching method (CDE), a reactive ion etching method (R
IE), an ion beam etching method and the like.
The coil shape is typically a spiral type or a spiral type, but a spiral type is preferable in order to obtain a high Q value. An insulating film and an upper magnetic film are formed on the insulating film pattern and the coil conductor that form the space between the coil conductors.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. Example 1

After forming a thermal oxide film 2 having a thickness of 1 μm on a Si single crystal substrate 1 having a diameter of 6 inches and a thickness of 0.6 mm, r
A lower magnetic film 3 made of a CoZrNb amorphous alloy having an average film thickness of 2 μm was formed by f magnetron sputtering. A SiO ₂ film 4 having an average film thickness of 12 μm was formed thereon by the plasma CVD method (shown in FIG. 1A).

A resist is applied on the SiO ₂ film 4, exposed through a photomask, and then developed to form a resist pattern 31 having a width of 2 μm in a width of 50 μm (corresponding to the coil conductor width) corresponding to the space between the spiral coil conductors. (Corresponding) intervals. Using the resist pattern 31 as a mask, the SiO ₂ film 4 is etched by RIE to obtain a width of 50
A groove having a depth of 1 μm and a depth of 10.5 μm was formed. With the resist pattern 31 left, an Al-Si film having an average film thickness of 1 nm is formed on the entire surface of the underlayer by a DC magnetron sputtering method.
A —Cu alloy film 21 was formed (see FIG. 1B).

The resist pattern 31 and the Al-Si-Cu alloy film 21 formed thereon are removed. On the Al-Si-Cu alloy film 21 at the bottom of the groove, heat C using dimethyl aluminum hydride (DMAlH) as a raw material.
An Al film 5 having a film thickness of 10 μm was selectively grown by the VD method and the inside of the groove was filled with a coil conductor. The Al film 5 has a (111) orientation, and the surface roughness R _max is about 200 n.
m (see FIG. 1 (c)).

After the SiO ₂ film 6 was formed on the entire surface by the plasma CVD method, the surface was flattened by etching back.
As a result, the surface roughness R _max was 10 nm. An upper magnetic film 7 made of CoZrNb amorphous alloy having the same composition and thickness as the lower magnetic film was formed thereon by rf magnetron sputtering to manufacture a planar inductor (shown in FIG. 1D).

In this embodiment, the SiO ₂ film 4 is patterned into a space between coil conductors to form an insulating film pattern having a high aspect ratio, and then a conductive film can be selectively grown on the surface of the insulating film pattern. Al-Si-C
Since the u alloy film 21 is formed, the Al film 5 can be easily filled and the coil conductor can be formed. Therefore, it is possible to manufacture a high-performance planar magnetic element having a small width between coil conductors and a coil conductor having a sufficient thickness.

During this process, the Si single crystal substrate 1 (diameter: 6 inches, thickness: 0.6 mm) did not significantly warp,
No problem occurred even if the device was manufactured on the entire surface of the substrate.

When a voltage of 50 V was applied between the coil terminals of the obtained planar inductor, dielectric breakdown was not observed. In addition, the same inductor was mounted on an Al ₂ O ₃ package, a terminal voltage of 10 V and a current of 0.8 A were applied, and a durability test was conducted for 100 hours under natural air cooling. As a result, a coil caused by electromigration, thermomigration, etc. No current leakage due to conductor breakage or dielectric breakdown was observed.

For the purpose of comparison, a planar inductor having the same specifications as those of the above-described embodiments is prepared by a conventional method in which a conductor film to be a coil conductor is formed, a space between conductors is formed by etching, and an insulating film is embedded in this space. I tried to manufacture. However, in a deep groove having an aspect ratio of 5, neither etching of the coil conductor nor filling of the insulating film was possible. Further, as a result of applying stress to the entire underlayer each time each thin film is formed, a large warp occurs in the underlayer, making it impossible to fabricate a device on the entire surface of the substrate. Example 2

On a glass substrate 11 having a diameter of 6 inches and a thickness of 0.6 mm, a CV containing a ketone hydrocarbon gas as a main raw material.
A polymer amorphous carbon film 12 having an average film thickness of 100 nm was formed by the D method. At this time, the carbon film 12 was (001) -oriented by controlling the film forming conditions. A lower magnetic film 3 made of CoZrNb amorphous alloy having an average film thickness of 2 μm was formed thereon by rf magnetron sputtering. A SiO ₂ film 4 having an average film thickness of 12 μm was formed thereon by a plasma CVD method using tetraethoxysilane (TEOS) as a raw material (FIG. 2).
(A) Illustration).

A resist is applied on the SiO ₂ film 4, exposed through a photomask, and then developed to form a resist pattern 31 having a width of 2 μm in a width of 50 μm (corresponding to the coil conductor width) corresponding to the space between the spiral coil conductors. (Corresponding) intervals. Using the resist pattern 31 as a mask, the SiO ₂ film 4 is etched by RIE to obtain a width of 50
A groove having a depth of 1 μm and a depth of 10.5 μm was formed. With the resist pattern 31 left, the exposed SiO ₂ surface was reduced using hydrogen plasma to form a polycrystalline Si film 22 (FIG. 2B).

The resist pattern 31 is removed, and tungsten hexafluoride (W) is formed on the polycrystalline Si film 22 at the bottom of the groove.
An average film thickness of 100 n by a CVD method using F ₆ ) as a main material.
The W film 23 of m was selectively grown. Dimethyl aluminum hydride (DMAlH) is formed on the W film 23 at the bottom of the groove.
An Al film 5 having a film thickness of 10 μm was selectively grown by a thermal CVD method using as a raw material, and the inside of the groove was filled with a coil conductor. This Al film 5 has a (111) orientation and a surface roughness R _max.
Was about 200 nm (shown in FIG. 2 (c)).

After the SiO ₂ film 6 was formed on the entire surface by the plasma CVD method, the surface was flattened by etching back.
As a result, the surface roughness R _max was 10 nm. A polymer amorphous carbon film 12 having an average film thickness of 100 nm was formed thereon by a CVD method using a ketone hydrocarbon gas as a main raw material. Then, by rf magnetron sputtering, C having the same composition and film thickness as the lower magnetic film is formed.
An upper magnetic film 7 made of oZrNb amorphous alloy was formed to manufacture a planar inductor (shown in FIG. 2D).

In this embodiment, after the SiO ₂ film 4 is patterned into the shape of the space between coil conductors to form an insulating film pattern having a high aspect ratio, a conductive film can be selectively grown on the surface of the insulating film pattern. Since the polycrystalline Si film 22 and the W film 23 are formed by reduction with hydrogen plasma, the Al film 5 can be easily filled and the coil conductor can be formed. Therefore, it is possible to manufacture a high-performance planar magnetic element having a small width between coil conductors and a coil conductor having a sufficient thickness.

Further, since the amorphous carbon film 12 is provided as the buffer layer, the glass substrate 11 (diameter 6 inches, thickness 0.6 mm) is not significantly warped during the process, and the device is manufactured on the entire surface of the substrate. Even so, no problem occurred.

When a voltage of 20 V was applied between the coil terminals of the obtained planar inductor, dielectric breakdown was not observed. In addition, when the same inductor was mounted in an Al ₂ O ₃ package, a terminal voltage of 10 V and a current of 1.0 A were applied, and a durability test was performed for 100 hours under natural air cooling, a coil caused by electromigration, thermomigration, etc. No current leakage due to conductor breakage or dielectric breakdown was observed.

For comparison, a planar inductor having the same specifications as those of the above-described embodiments is prepared by a conventional method in which a conductor film to be a coil conductor is formed, a space between conductors is formed by etching, and an insulating film is embedded in this space. Attempted to manufacture. However, in the deep groove having an aspect ratio of 10, neither etching of the coil conductor nor filling of the insulating film was possible. Further, as a result of applying stress to the entire underlayer each time each thin film is formed, a large warp occurs in the underlayer and the glass substrate breaks, making it impossible to fabricate devices on the entire surface of a large-sized substrate. . Even when a small-sized glass substrate was used, peeling of the thin film occurred during the process, resulting in a very low yield. Example 3

After the thermal oxide film 2 is formed on the Si single crystal substrate 1, the lower magnetic film 3 is formed by rf magnetron sputtering. The SiO ₂ film 14 is formed on the lower magnetic film 3.
To form. After forming a thin Al film 15 on the SiO ₂ film 14, it is patterned into a spiral coil conductor shape by photolithography. Plasma C
A thick SiO ₂ film 4 is formed by the VD method (FIG. 3A).
(Shown).

A mask material 32 is formed on the SiO ₂ film 4 by photolithography so as to correspond to the space between the conductors. Using the mask material 32 as a mask, SiO is formed by RIE.
_{2 The} film 4 is etched to form an insulating film in the space between conductors. At this time, the pattern of the Al film 15 is exposed (see FIG. 3).
(B) Illustration). A Cu film 25 is formed on the pattern of the Al film 15 by electroplating to form a coil conductor (shown in FIG. 3C).

The mask material 32 is removed, and SiO ₂ 6 is formed on the entire surface.
After forming the film, it is flattened by etching back. further,
The upper magnetic film 7 is formed to manufacture a planar inductor (shown in FIG. 3D).

In this embodiment, the insulating film is etched to form an insulating film pattern having a high aspect ratio, and then a material (Cu) having a small specific resistance is easily formed on the thin Al film 15 by using the electroplating method. Since it can be filled and a coil conductor can be formed, the coil resistance can be reduced. Therefore, it is possible to manufacture a high-performance planar inductor having a small width between coil conductor spaces and a coil conductor having a sufficient thickness. On the other hand, since the coil resistance can be reduced, the requirement for a high aspect ratio can be reduced. Example 4

After the thermal oxide film 2 is formed on the Si single crystal substrate 1, the lower magnetic film 3 is formed by rf magnetron sputtering. Plasma CV is formed on the lower magnetic film 3.
A thick SiO ₂ film 4 is formed by the D method (shown in FIG. 4A).

A mask material 32 is formed on the SiO ₂ film 4 by photolithography so as to correspond to the space between the spiral conductors. R using the mask material 32 as a mask
The SiO ₂ film 4 is etched by IE to form an insulating film in a space between conductors. At this time, the SiO ₂ film 4 having a certain thickness is left so as to be insulated from the lower magnetic film 3 (shown in FIG. 4B).

A resist 31 is selectively formed on the mask material 32.
To form. C on the entire surface by sputtering or vapor deposition
The u film 15 is formed to form a coil conductor (FIG. 4C).
(Shown).

The resist 31 is dissolved in an organic solvent and the Cu film formed on the resist 31 is lifted off. After removing the mask material 32 and forming the SiO ₂ film 6 on the entire surface,
Etch back and flatten. Further, the upper magnetic film 7 is formed to manufacture a planar inductor (shown in FIG. 4D).

In this embodiment, after the insulating film is etched to form an insulating film pattern having a high aspect ratio, a physical vapor deposition method (sputtering method or vapor deposition method) is used, and an etchback method is also used. Material with low specific resistance (C
Since u) can be easily filled and the coil conductor can be formed, the coil resistance can be reduced. Therefore, it is possible to manufacture a high-performance planar inductor having a small width between coil conductor spaces and a coil conductor having a sufficient thickness. On the other hand, since the coil resistance can be reduced, the requirement for a high aspect ratio can be reduced. Example 5

After forming the thermal oxide film 2 on the Si single crystal substrate 1, the lower magnetic film 3 is formed by rf magnetron sputtering. Plasma CV is formed on the lower magnetic film 3.
The SiO ₂ film 14 is formed by the D method. An Al film 5 is formed as a first conductor film on the SiO ₂ film 14 (shown in FIG. 5A).

A mask material (for example, S) is formed on the Al film 5 by photolithography so as to correspond to a region near the space between coil conductors in the spiral coil conductor region.
iO ₂ ) 33 is formed. Using the mask material 33 as a mask, the Al film 5 is etched by RIE to form a part of the coil conductor. In the groove between the patterns of the Al film 5,
The polyimide film 8 is filled (shown in FIG. 5B).

A mask material (eg, SiO ₂ ) 34 is formed thereon by photolithography in a region other than the region corresponding to the center of the coil conductor region. Using the mask material 34 as a mask, the polyimide film 8 in the region corresponding to the center of the coil conductor region is etched by RIE. As a result, the side surface of the Al film 5 is exposed (shown in FIG. 5C).

By the electric field plating method, a Cu film 25 is formed as a second conductor film in a region corresponding to the center of the coil conductor region, and a coil conductor composed of the Al film 5 and the Cu film 25 is formed. After removing the mask materials 33 and 34 and forming SiO ₂ 6 on the entire surface, it is flattened by etching back. Further, the upper magnetic film 7 is formed to manufacture a planar inductor (shown in FIG. 5D). Example 6

After the thermal oxide film 2 is formed on the Si single crystal substrate 1, the lower magnetic film 3 is formed by rf magnetron sputtering. Plasma CV is formed on the lower magnetic film 3.
The SiO ₂ film 14 is formed by the D method. A pattern of the Cu film 25 'is formed on the SiO ₂ film 14 corresponding to the center of the spiral coil conductor region. Further, an Al film 5 is formed as a first conductor film on the entire surface (shown in FIG. 6A).

A mask material (for example, SiO ₂ ) 33 is formed on the Al film 5 by photolithography in a region near the inter-coil conductor space in the coil conductor region. A by RIE using the mask material 33 as a mask
The I film 5 is etched to form a part of the coil conductor.
A polyimide film 8 is filled in the groove between the patterns of the Al film 5 (shown in FIG. 6B).

A mask material (for example, SiO ₂ ) 34 is formed thereon by photolithography in a region other than the region corresponding to the center of the coil conductor region. Using the mask material 34 as a mask, the polyimide film 8 in the region corresponding to the center of the coil conductor region is etched by RIE. As a result, the side surfaces of the Cu film 25 'and the Al film 5 are exposed (shown in FIG. 6C).

By the electric field plating method, a Cu film 25 is formed as a second conductor film in a region corresponding to the center of the coil conductor region, and a coil conductor composed of the Al film 5 and the Cu film 25 is formed. After removing the mask materials 33 and 34 and forming SiO ₂ 6 on the entire surface, it is flattened by etching back. Further, the upper magnetic film 7 is formed to manufacture a planar inductor (illustrated in FIG. 6D).

In Examples 5 and 6, the coil conductor was Cu.
And Al, and their specific resistance is determined by the cross-sectional area ratio of both. Therefore, the coil resistance can be made smaller than that of the coil conductor made of only Al. On the other hand, since the coil resistance can be reduced, the requirement for a high aspect ratio can be reduced.

[0064]

As described above in detail, by using the method of the present invention, it is possible to easily manufacture a high-performance planar magnetic element having a small width between coil conductors and a coil conductor having a sufficient thickness. This is a significant contribution to the practical application of the planar magnetic element.

[Brief description of drawings]

1A to 1D are cross-sectional views showing a manufacturing process of a planar inductor according to a first embodiment of the present invention.

2A to 2D are cross-sectional views showing a manufacturing process of a planar inductor according to a second embodiment of the present invention.

3A to 3D are cross-sectional views showing a manufacturing process of a planar inductor according to a third embodiment of the present invention.

4A to 4D are cross-sectional views showing the manufacturing process of the planar inductor according to the fourth embodiment of the present invention.

5A to 5D are cross-sectional views showing a manufacturing process of a planar inductor according to a fifth embodiment of the present invention.

6A to 6D are cross-sectional views showing the manufacturing process of the planar inductor according to the sixth embodiment of the present invention.

7 (a) and 7 (b) are predetermined inductances (L) in a plane in which a horizontal axis represents a line width (δ) of a spiral coil forming a planar inductor and a vertical axis represents a space (s) width. FIG. 3 is a characteristic diagram showing conditions under which resistance (R) is obtained.

FIG. 8 is a characteristic diagram showing the δ / p dependence of L / R normalized by a value of δ / p → 1 for a planar inductor.

FIG. 9 is a characteristic diagram showing the relationship between the specific resistance of the coil conductor and the skin depth, using the frequency as a parameter.

[Explanation of symbols]

1 ... Si substrate, 2 ... Thermal oxide film, 3 ... Lower magnetic film, 4 ... S
iO ₂ film, 5 ... Al film, 6 ... SiO ₂ film, 7 ... lower magnetic film, 8 ... polyimide film, 11 ... glass substrate, 12 ... carbon film, 15 ... Al film, 21 ... Al-Si-Cu alloy film , 22 ... Polycrystalline Si film, 23 ... W film, 25, 25 '...
Cu film, 31 ... Resist pattern, 32, 33, 34 ...
Mask material.

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[Procedure amendment]

[Submission date] September 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 4

[Correction method] Change

[Correction content]

FIG. 4 is a sectional view showing a manufacturing process of the planar inductor according to the fourth embodiment of the present invention.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

FIG. 6 is a sectional view showing a manufacturing process of the planar inductor according to the sixth embodiment of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Tomita 1 Komukai-shi Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Inside the Toshiba Research Institute, Inc. (72) Inventor Tetsuhiko Mizoguchi Komukai-shiba, Kawasaki-shi, Kanagawa Town No. 1 Toshiba Corporation Research Institute

Claims (4)

[Claims] 1. A step of forming an insulating film forming a space between coil conductors on a magnetic film, a step of patterning this insulating film into a shape of a space between coil conductors, and a conductive film selectively forming this insulating film pattern. Surface modification so that the insulating film pattern can be grown into a coil conductor, a step of selectively filling a gap between the insulating film patterns with a conductive film to form a coil conductor, a step of forming an insulating film on the entire surface, and a step of forming an insulating film on the insulating film. And a step of forming a magnetic film on the substrate. 2. A step of forming a thin conductor film pattern corresponding to a coil conductor pattern on a magnetic film via an insulating film, a step of forming an insulating film forming a space between coil conductors on the entire surface, and the insulating film. To form a coil conductor by patterning the conductor film in the shape of the space between coil conductors to expose the conductor film pattern, and filling the conductor film on the thin conductor film of the insulating film pattern with an electric field plating method to form a coil conductor. A method of manufacturing a planar magnetic element, comprising: a step of forming an insulating film on the entire surface; and a step of forming a magnetic film on the insulating film. 3. A step of forming an insulating film forming a space between coil conductors on a magnetic film, a step of patterning this insulating film into a shape of the space between coil conductors, and an organic solvent applied on the insulating film pattern. A step of forming a melted film,
A step of forming a coil conductor by filling the conductor film in the gap of the insulating film pattern by forming a conductor film on the entire surface by physical vapor deposition, and dissolving the film soluble in an organic solvent, A method for manufacturing a planar magnetic element, comprising: a step of removing the formed conductor film; a step of forming an insulating film on the entire surface; and a step of forming a magnetic film on the insulating film. 4. A step of forming a first conductor film on a magnetic film via an insulating film, and a coil conductor region to be formed by selectively etching the first conductor film, in the vicinity of a space between coil conductors. Corresponding to the central portion of the coil conductor in the coil conductor region to be formed, the step of forming the first conductor film pattern in the region corresponding to the above, the step of filling the gap between the first conductor film patterns with the insulating film. A step of selectively removing the insulating film filling the region, and a first step of removing the insulating film from the region.
A step of forming a coil conductor composed of the first and second conductor films by filling the second conductor film in the gap of the conductor film pattern by electroplating, and a step of forming an insulating film on the entire surface. And a step of forming a magnetic film on the insulating film.