JP2001053225A - Inductor element and manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an inductor element on a substrate in which loss is easy to produce, to effectively lower an induced substrate current and to reduce the loss of the substrate by forming depletion regions between the first conductivity injected region and the second conductivity injected region and a lower region along the second conductivity injected region. SOLUTION: A spiral conductive film 14 is formed on the first conductivity substrate 10. The second conductivity injected regions 24 are formed on the substrate 10 and at positions adjacent to a surface. The first conductivity injected region 22 surrounding the second conductivity injected regions 24 and being not brought into contact directly with the second conductivity injected regions 24 at a regular interval to the second conductivity injected regions 24 is formed. The first conductivity injected region 22 and the second conductivity injected regions 24 are connected electrically, and positive bias is applied to the second conductivity injected regions 24. A depletion region 20 is formed between the first conductivity injected region 22 and the second conductivity injected region 24 and in a lower region along the second conductivity injected region 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inductor (inducto).
r) device and its manufacturing method, in particular, substrate loss (substrate
radio frequency (RF: Rad)
io Frequency) inductors and a method of manufacturing the same.

[0002]

2. Description of the Related Art A general inductor is desirably manufactured on a lossless substrate made of a material such as gallium arsenide (GaAs) or sapphire.
Because this type of substrate has a very good insulating effect and can reduce the induced substrate current, it can provide a high quality inductor and good operation in the radio frequency (RF) range Because. However, a disadvantage of such materials such as gallium arsenide or sapphire is that they are too expensive to be widely used.

[0003]

For this reason, the current inductor is a method of manufacturing an inductor on a silicon substrate which can be obtained at a relatively low price by applying silicon technology. The inductor consumes a relatively large amount of energy when operating. Therefore, to prevent energy wastage,
An inductor element can be manufactured on a silicon substrate only after solving many problems. Conventionally, various methods for solving these problems, for example, local substrate removal
(local substrate removal)
d ground plane) methods have been proposed, but none of them are practical, and there are limits to the effects that can be achieved.

Accordingly, an object of the present invention is to provide an inductor that can be manufactured on a lossy substrate such as a silicon substrate, and that can effectively reduce the induced substrate current and reduce the substrate loss. And a method for manufacturing the same. It is a further object of the present invention not only to improve inductance, but also to reduce resistance and maintain parasitic capacitance to a minimum, while maintaining a relatively high oscillation frequency (oscilla).
It is an object of the present invention to provide an inductor and a method of manufacturing the same, which can realize a reduction in substrate loss by realizing an induction frequency.

[0005]

According to the present invention, an inductor capable of reducing substrate loss and a method of manufacturing the same have the following features. That is, a spiral conductive film having a spiral structure and both ends is formed on the first conductive type substrate, one end of which is connected to the input end and the other end of which is connected to the output end. The material of the spiral conductive film is preferably aluminum or copper. Next, a second conductivity type implantation region is formed in the substrate and at a position adjacent to the surface of the substrate. Furthermore, the second conductivity type implanted region is surrounded by the substrate and at a position adjacent to the surface of the substrate, and is spaced apart from the second conductivity type implanted region by a certain distance and is not in direct contact with the second conductivity type implanted region. A one conductivity type implantation region is formed. Next, a reverse bias source is provided to electrically connect the first conductivity type implanted region and the second conductivity type implanted region, e.g.
A positive bias is applied to the conductivity type injection region, and a negative bias is applied to the first conductivity type injection region. The reverse bias generates a depletion region between the first conductivity type implantation region and the second conductivity type implantation region and in a lower region along the second conductivity type implantation region. The planar shape of the above-described second conductivity type implantation region is a sheet-like implantation region parallel to the surface of the substrate, and the planar shape of the first conductivity type implantation region is a ring-shaped implantation region surrounding the second conductivity type implantation region. Area.

An inductor and a method of manufacturing the inductor according to the present invention, which can reduce the substrate loss, have the following features. That is, a spiral conductive film having a spiral structure and both ends is formed on the first conductive type substrate, one end of which is connected to the input end and the other end of which is connected to the output end. The material of the spiral conductive film is preferably aluminum or copper. Next, a first conductivity type injection region is formed in the substrate at a position adjacent to the substrate surface and below the spiral conductive film. The doping concentration of the first conductivity type implantation region is higher than the doping concentration of the first conductivity type substrate, and is desirably about 5 × 10 ¹⁹ atoms / cm ³ . First
It is desirable that the depth of the conductivity type injection region be several μm.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below with reference to the drawings. (First Embodiment) As shown in FIGS.
An insulating film 12 is formed on (for example, a P ^- type silicon substrate) 10. As a material of the insulating film, silicon dioxide (Si
O ₂ ) is desirable. A spiral conductive film is formed on the insulating film 12.
(spiral conductive layer) 14 is formed. It is preferable that the material of the conductive film contains aluminum, copper, or the like. The spiral conductive film 14 has a spiral structure 14a extending spirally in a plane and both ends, that is, a first end 14b and a second end 14c. The first end portion 14b is connected to a lower conductive film (under
It is connected to the input terminal 16 via a conductive layer 20 and a lead portion 14d. The lower conductive film 20 is the insulating film 1
2 is formed. On the other hand, the second end 14c is connected to the output end 18 via the lead 14e. The first end 14b is connected to the output end 18 via the lower conductive film 20 and the lead 14d, and the second end 14c is connected to the lead 14e.
May be connected to the input terminal 16 via the.

As shown in FIG. 1B, a silicon substrate 10
A first implantation region at a location adjacent to the silicon substrate surface
(implanted region) 22 is formed. The conductive type of the first implantation region is the opposite to the silicon substrate 10, for example, an N ⁺ implantation region. Further, a second implantation region 24 is formed in another portion of the silicon substrate 10 adjacent to the surface of the silicon substrate. The conductivity type of the second implantation region is the same as that of the silicon substrate 10, for example, a P ⁺ implantation region.
The doping concentration of the second implantation region 24 depends on the silicon substrate 1
Greater than zero. The second implantation region 24 is the first implantation region 22
, And has a certain distance from the first injection region 22 and is not in direct contact. The planar shape of the first implantation region 22 is a sheet-like implantation region substantially parallel to the surface of the silicon substrate 10, and the second implantation region 2
The planar shape of 4 is a ring-shaped injection region surrounding the first injection region 22. Next, the reverse bias source Vs
(inverse bias source) to electrically connect the first implantation region 22 and the second implantation region 24 to apply a reverse bias. For example, a positive bias is applied to the first implantation region 22 and a negative bias is applied to the second implantation region 24, or the second implantation region 24 is grounded. Due to this reverse bias, a depletion region (depletion region) 26 is formed in the silicon substrate 10 between the first implantation region 22 and the second implantation region 24 and below the first implantation region 22. The depletion region 26 preferably has a depth of about 0.5 to 18 μm below the first implantation region 22. The formation of such a depletion region 26 is one of the features of the present invention, and its purpose is to form the silicon substrate 10 and the spiral inductor
(Spiral conductive film) 14 is effectively separated from the silicon substrate 10 to reduce induced current generated in the silicon substrate 10.
Zero energy wear is to be minimized.

Tables 1 to 4 below show experimental data of the first embodiment according to the present invention.
3-D electromagnetic simulation (3-dim) of NNET EM
tension electromagnetic simulation) obtained by system software. Table 1 shows data when the material of the spiral conductive film is an ideal lossless metal and the inductance of the inductor is 0.15 nH. Table 2 shows data when the material of the spiral conductive film is aluminum and the thickness is 0.6 μm. Table 3 shows that the material of the spiral conductive film is copper,
These data are obtained when the thickness is set to 1.0 μm. Table 4
Means that the material of the spiral conductive film is copper and the thickness is 2.0 μm.
This is data when m is set.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

In each table, the depth of the depletion region 26 is set to 0 to 18 μm at different operation frequencies of the inductor element.
Equivalent electric resistance value Ref obtained by changing in the range of
f (effective resistance) is shown. The smaller the equivalent loss electric resistance value Ref, the smaller the wear of the silicon substrate 10 and the better the characteristics of the inductor element. Further, as the depth of the depletion region 26 increases, the equivalent wear electric resistance value Ref tends to decrease.

Second Embodiment As shown in FIGS. 2A and 2B, an insulating film 32 is formed on a substrate (eg, a P ^- type substrate) 30. The material of this insulating film is silicon dioxide
(SiO ₂ ) is desirable. The spiral conductive film 34 formed on the insulating film 32 is preferably made of aluminum, copper, or the like as a material of the conductive film. Spiral conductive film 3
Reference numeral 4 denotes a spiral structure 34a extending spirally in a plane and both ends thereof, that is, a first end 34b and a second end 34.
c. The first end 34b is connected to the input end 36 via the lower conductive film 40 and the lead 34d. The lower conductive film 40 is formed in the insulating film 32. On the other hand, the second end 34c is connected to the output end 38 via the lead 34e. The first end 34b may be connected to the output end 38 via the lower conductive film 40 and the lead 34d, and the second end 34c may be connected to the input end 36 via the lead 34e.

By ion implantation, an implantation region 42 is formed in the silicon substrate 30 at a position adjacent to the surface of the silicon substrate, as shown in FIG. The conductivity type of this implantation region is the same as that of the silicon substrate 30, for example, a P ⁺ implantation region. The ion concentration in this implanted region is
It is larger than the ion concentration in 0. The injection region 42 is formed below the spiral conductive film 34. The ion concentration of the implantation region 42 is desirably about 5 × 10 ¹⁹ atoms / cm ³ , and the thickness thereof is desirably several μm. The purpose of the implanted region 42 is to effectively separate the silicon substrate 30 and the spiral conductive film (spiral inductor) 34 so that the silicon substrate 30
And to minimize the energy consumption of the silicon substrate 30.

Table 5 shows that the inductance of the inductor 34 is 0.15 nH and the depth of the injection region 42 is 2.0 μm.
And the material of the spiral conductive film 34 is copper, and the thickness is 2.0 μm. As shown in Table 5, assuming that the depth of the implantation region 42 is 2.0 μm, the equivalent resistance electric resistance value Ref obtained thereby is as follows when the depth of the depletion region in the first embodiment is 6.0 μm. It is almost the same as the obtained equivalent wear electric resistance value Reff.

[0018]

[Table 5]

As described above, the present invention has been disclosed by the preferred embodiments. However, as will be easily understood by those skilled in the art, appropriate changes and modifications can be made within the technical idea of the present invention. Therefore, the scope of patent protection must be determined based on the claims and their equivalents.

[0020]

With the above arrangement, the inductor element and the manufacturing method according to the present invention not only improve the inductance, but also reduce the electric resistance and maintain the parasitic capacitance at the minimum value, thereby achieving a relatively high inductance. Since the oscillation frequency of the value can be realized and the substrate loss can be reduced, the industrial use value is high.

[Brief description of the drawings]

FIG. 1A is a plan view showing an inductor element according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA of FIG.

FIG. 2A is a plan view showing an inductor element according to a second embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along line BB of FIG.

[Explanation of symbols]

 Reference Signs List 10 silicon substrate 12 insulating film 14 spiral conductive film (spiral inductor) 14a spiral structure 14b first end 14c second end 14d lead 14e lead 16 input terminal 18 output terminal 20 lower conductive film 22 first injection region 24 Second injection region 26 Depletion region 30 Silicon substrate 32 Insulating film 34 Spiral conductive film (spiral inductor) 34a Spiral structure 34b First end 34c Second end 34d Lead 34e Lead 36 Input end 38 Output end 40 Lower conductive film 42 injection region

Claims (28)

[Claims] A first conductive type substrate; a spiral conductive film provided on the substrate, having a spiral structure and both ends, one end of which is connected to an input end, and the other end of which is connected to an output end. And a second provided in the substrate and adjacent to a surface of the substrate.
A conductivity type implantation region, provided in the substrate, adjacent to a surface of the substrate, surrounding a periphery of the second conductivity type implantation region, and having a certain distance between the second conductivity type implantation region A first conductivity type injection region, and an electrical connection with the first conductivity type injection region and the second conductivity type injection region, and provide a reverse bias to the first conductivity type injection region and the second conductivity type injection region. A reverse bias source; and a depletion region formed between the first conductivity type implantation region and the second conductivity type implantation region in the substrate and formed below the second conductivity type implantation region. An inductor element, characterized in that: 2. A step of providing a substrate of a first conductivity type, comprising a spiral structure and both ends provided on the substrate, one end of which is connected to an input end, and the other end of which is connected to an output end. Forming; forming a second conductivity type implanted region in the substrate adjacent to the surface of the substrate; and forming a periphery of the second conductivity type implanted region in the substrate adjacent to the surface of the substrate. Forming a first conductivity type implantation region surrounding the first conductivity type implantation region and having a certain distance between the first conductivity type implantation region and the second conductivity type implantation region. Providing a bias to form a depletion region between the first conductivity type implantation region and the second conductivity type implantation region in the substrate and below the second conductivity type implantation region. Induct that is characterized by Method of manufacturing over element. 3. The inductor device according to claim 1, wherein the depletion region is formed at a depth of about 0.5 to 18 μm below the second conductivity type injection region. 4. The method according to claim 2, wherein the depletion region is formed at a depth of about 0.5 to 18 μm below the second conductivity type implantation region. 5. The first conductivity type substrate is a P ⁻ substrate, the second conductivity type implantation region is an N ⁺ implantation region,
The inductor element according to claim 1, wherein the first conductivity type injection region is a P ⁺ injection region. 6. The first conductivity type substrate is a P ⁻ substrate, the second conductivity type implantation region is an N ⁺ implantation region,
The method according to claim 2, wherein the first conductivity type implantation region is a P ⁺ implantation region. 7. The planar shape of the second conductivity type injection region is as follows:
2. The inductor element according to claim 1, wherein the injection region is a sheet-like injection region substantially parallel to a surface of the first conductivity type substrate. 8. The planar shape of the second conductivity type injection region is as follows:
3. The method according to claim 2, wherein the injection region is a sheet-like injection region substantially parallel to the surface of the first conductivity type substrate. 9. The planar shape of the first conductivity type injection region is as follows:
2. The inductor element according to claim 1, wherein the ring-shaped injection region surrounds the second conductivity type injection region. 10. The method according to claim 2, wherein the planar shape of the first conductivity type implantation region is a ring-shaped implantation region surrounding the second conductivity type implantation region. 11. A first conductive type substrate, and a spiral conductive film provided on the substrate and having a spiral structure and both ends, one end of which is connected to an input end and the other end of which is connected to an output end. A first conductivity type implant provided in the substrate, adjacent to a surface of the substrate and located below the spiral conductive film, and having a doping concentration higher than the doping concentration of the first conductivity type substrate. An inductor element comprising a region. 12. A step of providing a first conductivity type substrate; and providing a spiral structure and both ends on the substrate, a spiral type conductive film having one end connected to an input end and the other end connected to an output end. Forming and ion-implanting a doping concentration in the substrate adjacent to the surface of the substrate and below the spiral conductive film, the doping concentration being greater than the doping concentration of the first conductivity type substrate. Forming a first conductivity type injection region having the first conductivity type. 13. The inductor element according to claim 11, wherein an implantation depth of the first conductivity type implantation region is several μm. 14. The method according to claim 12, wherein the implantation depth of the first conductivity type implantation region is several μm. 15. The inductor element according to claim 11, wherein an ion concentration of the first conductivity type implantation region is about 5 × 10 ¹⁹ atoms / cm ³ . 16. The method according to claim 12, wherein the ion concentration of the first conductivity type implantation region is about 5 × 10 ¹⁹ atoms / cm ³ . 17. The inductor element according to claim 11, wherein the first conductivity type substrate is a P ⁻ substrate, and the first conductivity type implantation region is a P ⁺ implantation region. 18. The method according to claim 12, wherein the first conductivity type substrate is a P ⁻ substrate, and the first conductivity type implantation region is a P ⁺ implantation region. 19. The method according to claim 1, wherein the material of the first conductivity type substrate includes silicon.
2. The inductor element according to 1. 20. The material according to claim 2, wherein the material of the first conductivity type substrate contains silicon.
3. The production method according to 2. 21. The inductor element according to claim 1, further comprising an insulating film formed between the first conductive type substrate and the spiral conductive film. 22. The method according to claim 2, wherein an insulating film is provided between the first conductive type substrate and the spiral conductive film. 23. The inductor element according to claim 21, wherein a material of the insulating film includes silicon dioxide. 24. The method according to claim 22, wherein a material of the insulating film includes silicon dioxide. 25. The inductor element according to claim 1, wherein the material of the spiral conductive film contains aluminum. 26. The method according to claim 2, wherein the material of the spiral conductive film contains aluminum. 27. The inductor element according to claim 1, wherein the material of the spiral conductive film contains copper. 28. The method according to claim 2, wherein the material of the spiral conductive film contains copper.