CN101034623A - Variable capacitor and method of making the same - Google Patents

Abstract

A capacitor manufacturing method provides variable capacitors whose capacitances remain stable under the influence of temperature change. Such a variable capacitor includes a fixed electrode, a movable electrode film facing the fixed electrode, and an anchor portion that provides partial connection between the fixed electrode and the movable electrode film. For making this variable capacitor, a first electrode is formed to serve as the fixed electrode. Then, an anchor portion is formed on the fixed electrode, and a sacrifice film is formed to cover the fixed electrode but partially expose the anchor portion. A second electrode is formed on the sacrifice film to serve as the movable electrode film, bonded to the anchor portion. Finally, the sacrifice film is removed.

Description

Variable capacitor and manufacture method thereof

Technical field

The present invention relates to variable capacitor and manufacture method thereof.

Background technology

At Wireless Telecom Equipment for example in the field of mobile phone, increase day by day for the demand of littler high-frequency circuit or RF circuit, so that reply is for realizing the increase of the necessary mounted component quantity of Premium Features institute.In response to this demand, people have carried out various effort, make the parts or the device miniaturization of forming circuit with utilization MEMS (MEMS (micro electro mechanical system)) technology.Variable capacitor is a kind of in these parts.In variable frequency reflector, tuned amplifier, impedance matching box circuit or the like, variable capacitor is absolutely necessary.For example, in following patent documentation 1 and 2, disclosed the variable capacitor that utilization MEMS technology is made.

Patent documentation 1:JP-A-2004-6588

Patent documentation 2:JP-A-2004-127973

Figure 86 is the partial cross section figure of conventional variable capacitor Y.Variable capacitor Y comprises substrate 91, fixed electrode 92, float electrode 93 and a pair of support portion 94.Float electrode 93 forms crane span structure in described support portion 94, and has a part of facing mutually with fixed electrode 92.Substrate 91 is fabricated from a silicon, and fixed electrode 92 and float electrode 93 are made by metal material.

In variable capacitor Y, when between fixed electrode 92 and float electrode 93, applying voltage, produce electrostatic attraction.Utilize electrostatic attraction, float electrode 93 can be pulled to fixed electrode 92, thereby change the distance between fixed electrode 92 and the float electrode 93.The electrostatic capacitance of variable capacitor Y, be that electrostatic capacitance between fixed electrode 92 and the float electrode 93 changes with this distance.Therefore,, can be applied to voltage between fixed electrode 92 and the float electrode 93, change electrostatic capacitance by change according to variable capacitor Y.Utilize this structure, predetermined voltage is applied between fixed electrode 92 and the float electrode 93 electrostatic capacitance that obtains to be scheduled to thereby drive variable capacitor Y.

In traditional variable capacitor Y, be not driven (not having voltage to be applied between fixed electrode 92 and the float electrode 93) even device is current, variations in temperature (for example temperature rising) also makes float electrode 93 bendings easily, shown in Figure 87 and Figure 88.This bending of float electrode 93 is that to have bigger coefficient of thermal expansion by float electrode 93 than substrate 91 caused.

Shown in Figure 87 and Figure 88, float electrode 93 in initial condition (state when device is not driven) when crooked float electrode 93 be different from shown in Figure 86 with distance between the fixed electrode 92, float electrode 93 distance between float electrode 93 and the fixed electrode 92 during bending in initial condition.Float electrode 93 crooked existence or do not exist and degree of crook can change the initial electrostatic electric capacity of variable capacitor Y in non operating state in non operating state.In addition, float electrode 93 crooked existence or do not exist and degree of crook also can change relation between variable capacitor Y electrostatic capacitance at work and the driving voltage (in order to obtain to be scheduled to electrostatic capacitance and voltage to be applied) in non operating state.In traditional variable capacitor Y, the intensity of variation of these factors is relatively large.

Summary of the invention

The present invention has been proposed in these cases.Therefore, the object of the present invention is to provide a kind of variable capacitor, it is suitable for reducing the electrostatic capacitance inconsistent (inconsistency) that caused by variations in temperature.Another object of the present invention is to provide a kind of manufacture method of above-mentioned variable capacitor.

According to first scheme of the present invention, provide a kind of variable capacitor.This variable capacitor comprises: fixed electrode; The float electrode film, it is in the face of this fixed electrode; And anchor portion (anchor portion) (making by dielectric material), it provides part to be connected between this fixed electrode and this float electrode film.

According to this variable capacitor, can between fixed electrode and float electrode film, produce electrostatic attraction by between fixed electrode and float electrode film, applying voltage, and by utilizing this electrostatic attraction, can with the piecemeal activity electrode film (except that the float electrode film be engaged to anchor portion the zone, be the junction surface) pull to fixed electrode, thereby change the interstitial volume between fixed electrode and the float electrode film.(the float electrode film is uneven towards the pulling amount or the pull distance of fixed electrode on whole float electrode film.Junction surface in the float electrode film is not mobile, and the float electrode film trends towards being pulled less amount near the zone at junction surface).The electrostatic capacitance of variable capacitor, be that electrostatic capacitance between fixed electrode and the float electrode film changes with interstitial volume.Therefore, according to this variable capacitor, can control electrostatic capacitance by the driving voltage that control is applied between fixed electrode and the float electrode film.

In addition, according to this variable capacitor, the float electrode film partly is connected with fixed electrode by anchor portion or partly is bonded on the fixed electrode.This has reduced the distortion or the bending of the float electrode film that caused by variations in temperature in work and the inoperative.For example, under fixed electrode is arranged on situation on the target substrate, even the coefficient of thermal expansion of float electrode film is different from the coefficient of thermal expansion of substrate, even and difference relatively large, the distortion or the bending of the float electrode film that is caused by variations in temperature also can diminish.Because the bending of float electrode film reduces in its original shape (shape in the inoperative), so in this variable capacitor, the inconsistent of initial electrostatic electric capacity during the inoperative reduces.In addition, because the distortion of the float electrode film that is caused by variations in temperature during work and the inoperative reduces, so the inconsistent of the work relationship between electrostatic capacitance and the driving voltage also reduces.As mentioned above, it is inconsistent that this variable capacitor is very suitable for reducing the electrostatic capacitance that caused by variations in temperature.Above-mentioned variable capacitor can highly precisely be worked.

Preferably, anchor portion penetrates fixed electrode and/or float electrode film.According to this kind configuration, fixed electrode and float electrode film one of them has through hole or opening at least, so that anchor portion is packed into.Fixed electrode does not have through any part of anchor portion in the face of the float electrode film, and the float electrode film does not have through any part of anchor portion in the face of fixed electrode yet.In other words, not through the localized capacitance device structure of the interelectrode distance constant (thereby electrostatic capacitance is fixed) of anchor portion.Have the fixedly localized capacitance device structure of electrostatic capacitance if variable capacitor comprises, then the minimum electrostatic capacitance of whole variable capacitor can't be less than this fixing electrostatic capacitance.On the contrary, the variable capacitor that does not comprise any localized capacitance device structure (it has fixedly electrostatic capacitance) does not have the restriction of this minimum electrostatic capacitance for whole variable capacitor.When device must provide less minimum electrostatic capacitance, the variable capacitor that does not comprise any localized capacitance device structure (it has fixedly electrostatic capacitance) was preferred, thereby was preferred for obtaining bigger rate of change or variable quantity.As mentioned above, the anchor portion configuration that penetrates fixed electrode and/or float electrode film is applicable to rate of change or the variable quantity that acquisition is bigger.

Preferably, in this variable capacitor, fixed electrode is provided with dielectric film in the face of a side of float electrode film, and/or the float electrode face is provided with dielectric film to a side of fixed electrode.Above-mentioned configuration has suitably prevented direct contact the between fixed electrode and the float electrode film.If be provided with dielectric film, then the part of dielectric film can constitute at least a portion of anchor portion.

Preferably, the float electrode film has the part that can contact with fixed electrode through dielectric film.Substitute above-mentioned configuration, perhaps except that above-mentioned configuration, the float electrode film can have the part that contacts with fixed electrode through dielectric film.These configurations are applicable to electrostatic capacitance change rate or the variable quantity that acquisition is bigger.When implementing these configurations, preferably, the float electrode film has the part towards the fixed electrode bending, perhaps has the part away from the fixed electrode bending.

Alternative plan of the present invention provides a kind of variable capacitor.This variable capacitor comprises: the first float electrode film respect to one another and the second float electrode film; And anchor portion (making by dielectric material), it provides part to be connected between this first float electrode film respect to one another and this second float electrode film.

According to this variable capacitor, can be by between the first float electrode film and the second float electrode film, applying voltage, and between the first float electrode film and the second float electrode film, produce electrostatic attraction, and by utilizing this electrostatic attraction, can with the float electrode film (except that these float electrode films be engaged to anchor portion the zone, be the junction surface) further each other, thereby change interstitial volume between the float electrode film.The electrostatic capacitance of this variable capacitor, be that electrostatic capacitance between the float electrode film changes with interstitial volume.Therefore, according to this variable capacitor, can control electrostatic capacitance by the driving voltage that control is applied between first and second float electrode film.

In addition, according to this variable capacitor, first and second float electrode film partly connects each other by anchor portion or engages.The distortion or the bending of first and second float electrode film that this has reduced to be caused by variations in temperature in work and the inoperative.Because the bending of two float electrode films reduces in its original shape (shape in the inoperative), so in this variable capacitor, the inconsistent of initial electrostatic electric capacity during the inoperative reduces.In addition, because the distortion of two the float electrode films causing of variations in temperature during work and the inoperative reduces, so the inconsistent of the work relationship between electrostatic capacitance and the driving voltage also reduces.As mentioned above, it is inconsistent that this variable capacitor is very suitable for reducing the electrostatic capacitance that caused by variations in temperature.Above-mentioned variable capacitor can highly precisely be worked.

Preferably, anchor portion penetrates the first float electrode film and/or the second float electrode film.According to this kind configuration, the first float electrode film and the second float electrode film one of them has through hole or opening at least, so that anchor portion is packed into.The first float electrode film does not have through any part of anchor portion in the face of the second float electrode film, and the second float electrode film does not have through any part of anchor portion in the face of the first float electrode film yet.In other words, not through the localized capacitance device structure of the interelectrode distance constant (thereby electrostatic capacitance is fixed) of anchor portion.As previously mentioned, when device must provide less minimum electrostatic capacitance, the variable capacitor that does not comprise any localized capacitance device structure (it has fixedly electrostatic capacitance) was preferred, thereby was preferred for obtaining bigger rate of change or variable quantity.As mentioned above, the anchor portion configuration that penetrates the first float electrode film and/or the second float electrode film is applicable to rate of change or the variable quantity that acquisition is bigger.

Preferably, according to this variable capacitor, the first float electrode face is provided with dielectric film to a side of the second float electrode film, and/or the second float electrode face is provided with dielectric film to a side of the first float electrode film.This kind configuration has prevented that suitably first and second float electrode film is in direct contact with one another.If be provided with dielectric film, then the part of dielectric film can constitute at least a portion of anchor portion.

Preferably, the first and second float electrode films can be in contact with one another through dielectric film.Substitute above-mentioned configuration, perhaps except that above-mentioned configuration, the first and second float electrode films partly are in contact with one another through dielectric film.These configurations are applicable to electrostatic capacitance change rate or the variable quantity that acquisition is bigger.When implementing these configurations, preferably, the first float electrode film has the part towards the second float electrode film bending, perhaps has the part away from the second float electrode film bending.Perhaps, preferably, the second float electrode film has the part towards the first float electrode film bending, perhaps has the part away from the first float electrode film bending.

Third party's case of the present invention provides a kind of manufacture method of variable capacitor.This method may further comprise the steps: form first electrode on substrate; On this first electrode, form anchor portion; Form the expendable film that covers this first electrode and partly expose this anchor portion; On this expendable film, form second electrode that is engaged to this anchor portion; And remove this expendable film.

Cubic case of the present invention provides a kind of manufacture method of variable capacitor.This method may further comprise the steps: form first electrode with opening on substrate; Form anchor portion, this anchor portion comprises the part of this opening of packing into and protrudes from the part of this first electrode; Form the expendable film that covers this first electrode and partly expose this anchor portion; On this expendable film, form second electrode that is engaged to this anchor portion; And remove this expendable film.

The 5th scheme of the present invention provides a kind of manufacture method of variable capacitor.This method may further comprise the steps: form first electrode on substrate; Form the expendable film that covers this first electrode, this expendable film has first opening that is used for partly exposing this first electrode; Form second electrode on this expendable film, this second electrode has second opening with this first open communication; By fill this first opening and this second opening at least with material, on this first electrode, form the anchor portion that penetrates this expendable film and this second electrode; And remove this expendable film.

The 6th scheme of the present invention provides a kind of manufacture method of variable capacitor.This method may further comprise the steps: form first electrode with first opening on substrate; Form expendable film, this expendable film has second opening with this first open communication, and covers this first electrode; Form second electrode on this expendable film, this second electrode has the 3rd opening with this second open communication; By filling this first opening, this second opening and the 3rd opening at least, form the anchor portion that penetrates this first electrode, this expendable film and this second electrode with material; And remove this expendable film.

Utilize the manufacture method of the variable capacitor that the 3rd to the 6th scheme of the present invention provides, can produce variable capacitor according to first and second schemes.

By following detailed description with reference to accompanying drawing, other features and advantages of the present invention will become apparent.

Description of drawings

Fig. 1 is the vertical view according to the variable capacitor of first embodiment of the invention.

Fig. 2 is according to the unshowned vertical view of the part of the variable capacitor of first embodiment of the invention.

Fig. 3 is the sectional view along III-III line among Fig. 1.

Fig. 4 is the part amplification sectional view along IV-IV line among Fig. 1.

Fig. 5 illustrates the different operating state of variable capacitor among Fig. 1.

Fig. 6 illustrates the manufacture method of variable capacitor among Fig. 1.

Fig. 7 is the sectional view of the first change example of variable capacitor among Fig. 1.

Fig. 8 illustrates the manufacture method of variable capacitor among Fig. 7.

Fig. 9 is the sectional view of the second change example of variable capacitor among Fig. 1.

Figure 10 illustrates the manufacture method of variable capacitor among Fig. 9.

Figure 11 is the sectional view of the 3rd change example of variable capacitor among Fig. 1.

Figure 12 illustrates the manufacture method of variable capacitor among Figure 11.

Figure 13 is the sectional view of the 4th change example of variable capacitor among Fig. 1.

Figure 14 is the sectional view of the 5th change example of variable capacitor among Fig. 1.

Figure 15 is the sectional view of the 6th change example of variable capacitor among Fig. 1.

Figure 16 is the vertical view according to the variable capacitor of second embodiment of the invention.

Figure 17 is according to the unshowned vertical view of the part of the variable capacitor of second embodiment of the invention.

Figure 18 is the sectional view along XVIII-XVIII line among Figure 16.

Figure 19 is the part amplification sectional view along XIX-XIX line among Figure 16.

Figure 20 illustrates the different operating state of variable capacitor among Figure 16.

Figure 21 illustrates the part manufacture method of variable capacitor among Figure 16.

Figure 22 illustrates the follow-up step of Figure 21.

Figure 23 is the sectional view of the first change example of variable capacitor among Figure 16.

Figure 24 is the sectional view of the second change example of variable capacitor among Figure 16.

Figure 25 is the sectional view of the 3rd change example of variable capacitor among Figure 16.

Figure 26 is the sectional view of the 4th change example of variable capacitor among Figure 16.

Figure 27 is the sectional view of the 5th change example of variable capacitor among Figure 16.

Figure 28 is the sectional view of the 6th change example of variable capacitor among Figure 16.

Figure 29 is the sectional view of the 7th change example of variable capacitor among Figure 16.

Figure 30 is the sectional view of the 8th change example of variable capacitor among Figure 16.

Figure 31 is the sectional view of the 9th change example of variable capacitor among Figure 16.

Figure 32 is the sectional view of the tenth change example of variable capacitor among Figure 16.

Figure 33 is the sectional view of the 11 change example of variable capacitor among Figure 16.

Figure 34 is the sectional view of the 12 change example of variable capacitor among Figure 16.

Figure 35 is the sectional view of the 13 change example of variable capacitor among Figure 16.

Figure 36 is the sectional view of the 14 change example of variable capacitor among Figure 16.

Figure 37 is the sectional view of the 15 change example of variable capacitor among Figure 16.

Figure 38 is the sectional view of the 16 change example of variable capacitor among Figure 16.

Figure 39 is the sectional view of the 17 change example of variable capacitor among Figure 16.

Figure 40 is the sectional view of the 18 change example of variable capacitor among Figure 16.

Figure 41 is the sectional view of the 19 change example of variable capacitor among Figure 16.

Figure 42 is the sectional view of the 20 change example of variable capacitor among Figure 16.

Figure 43 is the sectional view of the 21 change example of variable capacitor among Figure 16.

Figure 44 is the sectional view of the 22 change example of variable capacitor among Figure 16.

Figure 45 is the vertical view according to the variable capacitor of third embodiment of the invention.

Figure 46 is according to the unshowned vertical view of the part of the variable capacitor of third embodiment of the invention.

Figure 47 is the sectional view along XLVII-XLVII line among Figure 45.

Figure 48 is the part amplification sectional view along XLVIII-XLVIII line among Figure 45.

Figure 49 illustrates the different operating state of variable capacitor among Figure 45.

Figure 50 illustrates the part manufacture method of variable capacitor among Figure 45.

Figure 51 is the sectional view of the first change example of variable capacitor among Figure 45.

Figure 52 is the sectional view of the second change example of variable capacitor among Figure 45.

Figure 53 illustrates the sectional view of the stopper with lid.

Figure 54 is the sectional view according to the variable capacitor of fourth embodiment of the invention.

Figure 55 is the part amplification sectional view according to the variable capacitor of fourth embodiment of the invention.

Figure 56 illustrates the part manufacture method of variable capacitor among Figure 54.

Figure 57 is the sectional view of the first change example of variable capacitor among Figure 54.

Figure 58 is the sectional view of the second change example of variable capacitor among Figure 54.

Figure 59 is the sectional view according to the variable capacitor of fifth embodiment of the invention.

Figure 60 is the part amplification sectional view according to the variable capacitor of fifth embodiment of the invention.

Figure 61 illustrates the part manufacture method of variable capacitor among Figure 59.

Figure 62 is the sectional view of the change example of variable capacitor among Figure 59.

Figure 63 illustrates the sectional view of the stopper with lid.

Figure 64 is the vertical view according to the variable capacitor of sixth embodiment of the invention.

Figure 65 is according to the unshowned vertical view of the part of the variable capacitor of sixth embodiment of the invention.

Figure 66 is the sectional view along LXVI-LXVI line among Figure 64.

Figure 67 is the part amplification sectional view along LXVII-LXVII line among Figure 64.

Figure 68 illustrates the different operating state of variable capacitor among Figure 64.

Figure 69 illustrates the part manufacture method of variable capacitor among Figure 64.

Figure 70 illustrates the follow-up step of Figure 69.

Figure 71 is the sectional view of the first change example of variable capacitor among Figure 64.

Figure 72 is the sectional view of the second change example of variable capacitor among Figure 64.

Figure 73 illustrates the sectional view of the stopper with lid.

Figure 74 is the sectional view according to the variable capacitor of seventh embodiment of the invention.

Figure 75 is the part amplification sectional view according to the variable capacitor of seventh embodiment of the invention.

Figure 76 illustrates the part manufacture method of variable capacitor among Figure 74.

Figure 77 illustrates the follow-up step of Figure 76.

Figure 78 is the sectional view of the first change example of variable capacitor among Figure 74.

Figure 79 is the sectional view of the second change example of variable capacitor among Figure 74.

Figure 80 is the sectional view according to the variable capacitor of eighth embodiment of the invention.

Figure 81 is the part amplification sectional view according to the variable capacitor of eighth embodiment of the invention.

Figure 82 illustrates the part manufacture method of variable capacitor among Figure 80.

Figure 83 illustrates the follow-up step of Figure 82.

Figure 84 is the sectional view of the change example of variable capacitor among Figure 80.

Figure 85 illustrates the sectional view of the stopper with lid.

Figure 86 is the partial cross section figure of conventional variable capacitor.

Figure 87 illustrates a state of float electrode film thermal expansion in the conventional variable capacitor of Figure 86.

Figure 88 illustrates another state of float electrode film thermal expansion in the conventional variable capacitor of Figure 86.

Embodiment

Fig. 1 to Fig. 4 illustrates the variable capacitor X1 according to first embodiment of the invention.Fig. 1 is the vertical view of variable capacitor X1.Fig. 2 is the unshowned vertical view of the part of variable capacitor X1.Fig. 3 is the sectional view along III-III line among Fig. 1.Fig. 4 is the part amplification sectional view along IV-IV line among Fig. 1.

Variable capacitor X1 comprises substrate 11, fixed electrode 12, float electrode 13 (not shown among Fig. 2) and dielectric film 14.Substrate 11 for example is fabricated from a silicon.Fixed electrode 12 is formed on the substrate 11.Float electrode 13 is implemented on the substrate 11.As shown in Figure 4, float electrode 13 has thickness T 1, for example is 1 to 2 μ m.Show that as clear among Fig. 1 fixed electrode 12 intersects mutually with float electrode 13, part relatively each other.Relative zone for example has 10000 to 40000 μ m ²Area.Distance L 1 among Fig. 4 between fixed electrode 12 and the float electrode 13 for example is 0.5 to 2 μ m.Preferably, fixed electrode 12 and one of float electrode 13 ground connection.For example aluminium (Al) and copper (Cu) form by electric conducting material for described fixed electrode 12 and float electrode 13.Dielectric film 14 is formed on fixed electrode 12 top sides to float electrode 13, and comprises anchor portion 14a as shown in Figure 3 and Figure 4.Dielectric film 14 prevents that suitably fixed electrode 12 and float electrode 13 are in direct contact with one another.Anchor portion 14a is clipped between fixed electrode 12 and the float electrode 13, provides part to be connected between fixed electrode 12 and float electrode 13.Dielectric film 14 for example has the thickness of 0.1 to 0.5 μ m.Dielectric film 14 is by dielectric material aluminium oxide (Al for example ₂O ₃), silica (SiO ₂) and silicon nitride (SiN _x) form.The prescribed route pattern (not shown) that is electrically connected with fixed electrode 12 or float electrode 13 is formed on the substrate 11.

According to variable capacitor X1 with above-mentioned structure, can between fixed electrode 12 and float electrode 13, produce electrostatic attraction by between fixed electrode 12 and float electrode 13, applying voltage, and by utilizing this electrostatic attraction, float electrode 13 can be pulled to fixed electrode 12 in the face of the part of fixed electrode 12 (except that the zone that is engaged to anchor portion 14a, be the junction surface 13 '), thus change as shown in Figure 5 fixed electrode 12 and the volume of the clearance G 1 between the float electrode 13.(towards the pulling amount of fixed electrode 12 or pull distance in float electrode 13 in the face of being uneven on the whole zone of fixed electrode 12.Junction surface 13 ' is not mobile, and float electrode 13 trends towards being pulled less amount near the zone at junction surface 13 ').The electrostatic capacitance of variable capacitor X1 changes with interstitial volume.Therefore, according to variable capacitor X1, can control electrostatic capacitance by the driving voltage (for example 0 to 20V) that control is applied between fixed electrode 12 and the float electrode 13.

In addition, according to variable capacitor X1, float electrode 13 partly is connected with fixed electrode 12 at anchor portion 14a place or partly is bonded on the fixed electrode 12; This has reduced the distortion or the bending of the float electrode 13 that caused by variations in temperature in work and the inoperative.Particularly, even the coefficient of thermal expansion of float electrode 13 is different from the coefficient of thermal expansion of substrate 11, even and difference relatively large, the distortion or the bending of the float electrode 13 that is caused by variations in temperature also can diminish.Because the bending of float electrode 13 reduces in its original shape (shape in the inoperative), so in variable capacitor X1, inconsistent the reducing of the initial electrostatic electric capacity during the inoperative (for example 0.5 to 1pF).In addition, because the distortion of the float electrode 13 that is caused by variations in temperature during work and the inoperative reduces, so the inconsistent of the relation between electrostatic capacitance and the driving voltage also reduces.As mentioned above, it is inconsistent that variable capacitor X1 is very suitable for reducing the electrostatic capacitance that caused by variations in temperature.Above-mentioned variable capacitor X1 can highly precisely work.

In addition, according to variable capacitor X1, can change electrostatic capacitance significantly.In traditional variable capacitor Y, float electrode 93 must move in limited range, draws in (pull-in) phenomenon so that avoid so-called.Drawing in phenomenon is a kind of like this phenomenon, that is: for example when variable capacitor Y is driven, float electrode 93 is moved on the fixed electrode 92 at once in the face of the whole zone of fixed electrode 92.The reason that this phenomenon takes place is: when device was driven, float electrode 93 was pulled to fixed electrode 92 substantially equably or with essentially identical amount on whole relative zone.When in the variable capacitor (variable capacitor Y) this to the distance between the electrode for capacitors (fixed electrode 92 and float electrode 93) become less than initial range (i.e. distance when electrode for capacitors is in their initial position) 2/3rds the time, draw in phenomenon probably.In case phenomenon has taken place to draw in, then variable capacitor in fact becomes uncontrollable.For fear of for example above-mentioned phenomenon of drawing in, in traditional variable capacitor Y, the moving range of float electrode 93 is limited, thereby can't change electrostatic capacitance on relative broad range.On the contrary, according to variable capacitor X1 provided by the invention, when being driven by device towards amount of movement that the pulling of fixed electrode 12 causes in the whole opposed area of float electrode 13 or in the face of inhomogeneous on the zone of fixed electrode 12, and shown in Fig. 5 (c) and Fig. 5 (d), can make float electrode 13 contact or push thereon with fixed electrode 12 parts through dielectric film 14, and the area of further control section contact.Therefore, according to variable capacitor X1, can change to the contact area of fixed electrode 12 between dielectric film 14 and float electrode 13 significantly and reach peaked state (for example state shown in Fig. 5 (d)) with the interstitial volume between fixed electrode 12 and the float electrode 13 from the initial condition shown in Fig. 5 (a).Therefore, variable capacitor X1 can provide big electrostatic capacitance change amount or rate of change.

Fig. 6 illustrates the manufacture method of variable capacitor X1 with a series of sectional views that correspond respectively to cross section shown in Figure 3.This method utilizes so-called MEMS technology to make variable capacitor X1.

In the manufacturing of variable capacitor X1, at first shown in Fig. 6 (a), fixed electrode 12 and dielectric film 14 are formed on the substrate 11 stackedly.For example can form dielectric film 14 by on the aluminium film, carrying out patterning; Promptly at first on substrate 11, form aluminium (Al) film, on the Al film, form Al then by sputter by sputter ₂O ₃Film comes etching Al after have the mask of predetermined resist pattern ₂O ₃Film.Come etching aluminium film by mask, on substrate 11, fixed electrode 12 is carried out patterning through having another predetermined resist pattern.

Then, shown in Fig. 6 (b), form expendable film 15.Expendable film 15 has: opening 15a is used for partly exposing dielectric film 14; And a plurality of opening 15b, be used for partly exposing substrate 11.Dielectric film 14 will become aforesaid anchor portion 14a by the zone that opening 15a exposes.For example provide expendable film 15 by photoresist.For example can form expendable film 15: at first on substrate, form the film of expendable material, to cover fixed electrode 12 and dielectric film 14 by sputter by following steps; Mask through having predetermined resist pattern comes this film of etching then.By controlling the thickness of the expendable film 15 that forms in this step, can control the initial condition distance L 1 between the fixed electrode 12 and float electrode 13 among the variable capacitor X1 of gained.

Then, shown in Fig. 6 (c), form float electrode 13.For example form float electrode 13 by following steps: at first form the aluminium film by sputter on expendable film 15 and among opening 15a, the 15b, the mask through having predetermined resist pattern comes etching Al film then.The float electrode 13 of Xing Chenging is engaged to dielectric film 14 in the opening 15a of expendable film 15 like this, and is engaged to substrate 11 in opening 15b.Note that in the drawings that in order to simplify two ends of float electrode 13 are depicted as and form by the opening 15b that fills expendable film 15 with electric conducting material.

Then, shown in Fig. 6 (d), remove expendable film 15.Particularly, utilize predetermined resist remover to remove expendable film 15 by wet etch method.After the above-mentioned steps, can successfully produce variable capacitor X1.

Fig. 7 is the sectional view that first of variable capacitor X1 becomes example.This figure is corresponding to Fig. 4 that the cross section of variable capacitor X1 among Fig. 1 is shown.In variable capacitor X1, dielectric film 14 is formed on fixed electrode 12 top sides to float electrode 13; Substitute this kind configuration, dielectric film 14 can be formed on float electrode 13 top sides to fixed electrode 12, as shown in Figure 7.

Fig. 8 illustrates first with a series of sectional views that correspond respectively to cross section shown in Figure 7 and becomes routine manufacture method.In the method, at first, fixed electrode 12 is formed on the substrate 11, shown in Fig. 8 (a).Then, shown in Fig. 8 (b), form expendable film 15.Expendable film 15 has: opening 15a is used for partly exposing fixed electrode 12; And another opening, be used for partly exposing substrate 11, as described in reference Fig. 6 (b).Then, shown in Fig. 8 (c), on expendable film 15 and open among the 15a and to form dielectric film 14.Therefore, dielectric film 14 is formed on a part among the opening 15a will become the anchor portion 14a that is connected and fixed electrode 12 and float electrode 13.Then, shown in Fig. 8 (d), form float electrode 13, thereafter, remove expendable film 15 by wet etching.After the above-mentioned steps, can successfully produce the first change example of variable capacitor X1 in Fig. 7.

Fig. 9 is the sectional view that second of variable capacitor X1 becomes example.This figure is corresponding to Fig. 4 that the cross section of variable capacitor X1 among Fig. 1 is shown.In variable capacitance X1, dielectric film 14 is formed on fixed electrode 12 top sides to float electrode 13; In addition, dielectric film 14 also can be formed on float electrode 13 top sides to fixed electrode 12, as shown in Figure 9.

Figure 10 illustrates second with a series of sectional views that correspond respectively to cross section shown in Figure 9 and becomes routine manufacture method.In the method, at first, fixed electrode 12 and dielectric film 14 are formed on the substrate 11 stackedly, shown in Figure 10 (a).Then, shown in Figure 10 (b), form expendable film 15.Expendable film 15 has: opening 15a is used for partly exposing dielectric film 14; And another opening, be used for partly exposing substrate 11, as described in reference Fig. 6 (b).The part that dielectric film 14 exposes by opening 15a will become the part of the anchor portion 14a that is connected and fixed electrode 12 and float electrode 13.Then, shown in Figure 10 (c), form another dielectric film 14 on expendable film 15 and among the opening 15a.This another dielectric film 14 is formed on a part among the opening 15a will become a part that is connected and fixed electrode 12 and the anchor portion 14a of float electrode 13.Then, shown in Figure 10 (d), form float electrode 13, thereafter, remove expendable film 15 by wet etching.After the above-mentioned steps, can successfully produce the second change example of variable capacitor X1 in Fig. 9.

Figure 11 is the sectional view that the 3rd of variable capacitor X1 becomes example.This figure is corresponding to Fig. 4 that the cross section of variable capacitor X1 among Fig. 1 is shown.In variable capacitor X1, float electrode 13 can have shape as shown in figure 11.Float electrode 13 according to this change example has an original shape, and it comprises the part away from fixed electrode 12 bendings.When the float electrode 13 with this shape is driven, at first contact with end 13a shown in Figure 11 in the face of the regional internal fixation electrode 12 of fixed electrode 12 through dielectric film 14 in float electrode 13.It is fixed electrode 12 that end 13a also leaves dielectric film 14 at last.The advantage of the shape of float electrode 13 shown in Figure 11 is that this shape has guaranteed that duration of work float electrode 13 contacts with the potential part of fixed electrode 12 through dielectric film 14.In addition, the small distance between the electrode for capacitors can be driven electrode for capacitors with low voltage.Therefore, consider low voltage operating, this configuration (wherein distance between electrodes is shorter at some position) shown in this change example is preferred.

Figure 12 illustrates the 3rd with a series of sectional views that correspond respectively to cross section shown in Figure 11 and becomes routine manufacture method.In the method, at first, fixed electrode 12, dielectric film 14 and expendable film 15 are formed on the substrate 11 stackedly, shown in Figure 12 (a).Particularly, will carry out with reference to Fig. 6 (a) and the described identical process of Fig. 6 (b).

Then, shown in Figure 12 (b), on expendable film 15, form resist pattern 16.For example can form resist pattern 16: at first, form predetermined resist film on substrate 11, on the expendable film 15 and among the opening 15a by following steps; Then, utilize photoetching that this resist film is carried out patterning.By the thickness of control resist pattern 16, can control the degree of above-mentioned bending in the float electrode 13.Adopt heat treatment so that resist pattern 16 be out of shape, as Figure 12 (c) shown in thereafter.

Then, shown in Figure 12 (d), form float electrode 13.For example can form float electrode 13 by following steps: at first, on substrate 11, on the expendable film 15, utilize sputtering method to form the aluminium film on the resist pattern 16 and among the opening 15a; Then, the mask through having predetermined resist pattern comes etching Al film., for example carry out wet etching, in one step or a plurality of independent step, to remove expendable film 15 and resist pattern 16 thereafter.After the above-mentioned steps, can successfully produce the three change example of variable capacitor X1 in Figure 11.

Meander electrode for example the 3rd float electrode 13 that becomes in the example can be made by the film that stacked multilayer (for example two-layer) has different internal stresss (tensile stress, compression stress) each other.Particularly, go up the stacked electrode of patterning, remove expendable film then at expendable film (for example expendable film among Figure 12 15).This process has stayed according to the internal stress difference in each layer of multilayer electrode and along the multilayer electrode of predetermined direction bending.Also can form float electrode with bend of describing after a while by these methods.

Figure 13 is the sectional view that the 4th of variable capacitor X1 becomes example.This figure is corresponding to Fig. 4 that the cross section of variable capacitor X1 among Fig. 1 is shown.In variable capacitor X1, float electrode 13 can have shape as shown in figure 13.Become in the example at this, float electrode 13 has an original shape, and it comprises the part away from fixed electrode 12 bendings; And float electrode 13 has end 13b shown in Figure 13, and the regional inner end 13b in the face of fixed electrode 12 contacts or is pressed thereon with fixed electrode 12 through dielectric film 14 in float electrode 13.When the float electrode 13 with this shape was driven, float electrode 13 changed along with the driving of device with the area that fixed electrode 12 contacts through dielectric film 14, and with end 13b shown in Figure 13 as basic point.Along with the distance between the electrode for capacitors diminishes, it is big that the electrostatic attraction that produces between electrode under given voltage trends towards becoming.Therefore, consider the low voltage operating of variable capacitor X1, float electrode 13 is preferred through this configuration that dielectric film 14 contacts with fixed electrode 12 parts.

Figure 14 is the sectional view that the 5th of variable capacitor X1 becomes example.This figure is corresponding to Fig. 4 that the cross section of variable capacitor X1 among Fig. 1 is shown.In variable capacitor X1, float electrode 13 can have shape as shown in figure 14.Float electrode 13 according to this change example has an original shape, and it comprises the part towards fixed electrode 12 bendings.When the float electrode 13 with this shape is driven, at first contact with part 13c shown in Figure 14 in the face of the regional internal fixation electrode 12 of fixed electrode 12 through dielectric film 14 in float electrode 13.It is fixed electrode 12 that part 13c also leaves dielectric film 14 at last.The advantage of the shape of float electrode 13 shown in Figure 14 is that this shape has guaranteed that duration of work float electrode 13 contacts with the potential part of fixed electrode 12 through dielectric film 14.

Figure 15 is the sectional view that the 6th of variable capacitor X1 becomes example.This figure is corresponding to Fig. 4 that the cross section of variable capacitor X1 among Fig. 1 is shown.In variable capacitor X1, float electrode 13 can have shape as shown in figure 15.Become in the example at this, float electrode 13 has an original shape, it comprises that towards the part of fixed electrode 12 bendings and part 13d shown in Figure 15 in the face of in the zone of fixed electrode 12, described part 13d contacts with fixed electrode 12 through dielectric film 14 in float electrode 13.When the float electrode 13 with this shape was driven, float electrode 13 changed along with the driving of device with the area that fixed electrode 12 contacts through dielectric film 14, and with part 13d shown in Figure 15 as basic point.Consider the low voltage operating of variable capacitor X1, the configuration that float electrode 13 has the original shape that contacts with fixed electrode 12 parts through dielectric film 14 is preferred.

Figure 16 to Figure 19 illustrates the variable capacitor X2 according to second embodiment of the invention.Figure 16 is the vertical view of variable capacitor X2.Figure 17 is the unshowned vertical view of the part of variable capacitor X2.Figure 18 is the sectional view along XVIII-XVIII line among Figure 16.Figure 19 is the part amplification sectional view along XIX-XIX line among Figure 16.

Variable capacitor X2 comprises substrate 21, float electrode 22, float electrode 23 (not shown among Figure 17) and dielectric film 24.Substrate 21 has groove 21a, and for example is fabricated from a silicon.Float electrode 22 has two ends that are engaged to substrate 21, and extends above groove 21a.Float electrode 23 is implemented on the substrate 21.As shown in figure 19, float electrode 23 has thickness T 2, for example is 1 to 2 μ m.Show that as clear among Figure 16 float electrode 22,23 is intersected mutually, part relatively each other.Relative zone for example has 10000 to 40000 μ m ²Area.Distance L 2 between the float electrode shown in Figure 19 22 and 23 for example is 0.5 to 2 μ m.Preferably, one of float electrode 22,23 ground connection.Described float electrode the 22, the 23rd, for example Al and Cu form by electric conducting material.Dielectric film 24 is formed on float electrode 22 top sides to float electrode 23, and comprises as Figure 18 and anchor portion 24a shown in Figure 19.Dielectric film 24 prevents that suitably float electrode 22,23 is in direct contact with one another.Anchor portion 24a is clipped between the float electrode 22,23, provides part to connect between float electrode 22,23.Dielectric film 24 for example has the thickness of 0.1 to 0.5 μ m.Described dielectric film 24 is by dielectric material Al for example ₂O ₃, SiO ₂And SiN _xForm.Be formed on the substrate 21 with float electrode 22 or the prescribed route pattern (not shown) that is electrically connected with float electrode 23.

According to variable capacitor X2 with above-mentioned structure, can between float electrode 22,23, produce electrostatic attraction by between float electrode 22,23, applying voltage, and by utilizing this electrostatic attraction, float electrode 22,23 (except that the zone that is engaged to anchor portion 24a, be the bonding land 22 ', 23 ') can be furthered each other, thereby change the volume of the clearance G 2 between as shown in figure 20 the float electrode 22,23.The electrostatic capacitance of variable capacitor X2 changes with interstitial volume.Therefore, according to variable capacitor X2, can control electrostatic capacitance by the driving voltage (for example 0 to 20V) that control is applied between the float electrode 22,23.

In addition, according to variable capacitor X2, float electrode 22,23 partly connects each other by anchor portion 24a or engages; This has reduced the distortion or the bending of the float electrode 22,23 that caused by variations in temperature in work and the inoperative.Because the bending of float electrode 22,23 reduces in its original shape (shape in the inoperative), so in variable capacitor X2, inconsistent the reducing of the initial electrostatic electric capacity during the inoperative (for example 0.5 to 1pF).In addition, because the distortion of the float electrode 22,23 that is caused by variations in temperature during work and the inoperative reduces, so the inconsistent of the relation between electrostatic capacitance and the driving voltage also reduces.As mentioned above, it is inconsistent that variable capacitor X2 is very suitable for reducing the electrostatic capacitance that caused by variations in temperature.Above-mentioned variable capacitor X2 is very suitable for highly precisely working.

In addition, according to variable capacitor X2, can change electrostatic capacitance significantly.As already explained, in traditional variable capacitor Y, can't change electrostatic capacitance significantly, this is because float electrode 93 must move in limited range, so that avoided drawing in phenomenon.On the contrary, when driving, shown in Figure 20 (c) and Figure 20 (d), can make float electrode 22,23 through dielectric film 24 part contact each other according to variable capacitor X2 of the present invention, and the further area that contacts of control section.Therefore, according to variable capacitor X2, can be with the interstitial volume between the float electrode 22,23 from the initial condition shown in Figure 20 (a), change to significantly that the contact area through dielectric film 24 reaches peaked state (for example state shown in Figure 20 (d)) between the float electrode 22,23.Therefore, variable capacitor X2 can provide big electrostatic capacitance change amount or rate of change.

Figure 21 and Figure 22 illustrate the manufacture method of variable capacitor X2 with a series of sectional views that correspond respectively to cross section shown in Figure 180.This method utilizes so-called MEMS technology to make variable capacitor X2.

In the manufacturing of variable capacitor X2, at first, preparation has the substrate 21 of groove 21a shown in Figure 21 (a).For example the mask through having predetermined resist pattern carries out anisotropic dry etch to predetermined silicon substrate, can form the substrate 21 with groove 21a.The example that can be used for the anisotropic dry etch of this technology is reactive ion etching (RIE).

Then, shown in Figure 21 (b), expendable material 25 is filled among the groove 21a of substrate 21.Particularly, for example can use sputtering method that expendable material is filled among the groove 21a, and use expendable material 25 to cover substrate 21, then expendable material excessive on the substrate 21 25 polishings be fallen more than capacity.For example provide expendable material 25 by photoresist.

Then, shown in Figure 21 (c), on substrate 21, form float electrode 22 and dielectric film 24 stackedly.Can utilize and form float electrode 22 and dielectric film 24 with reference to the described identical process of fixed electrode 12 and dielectric film 14 that is used to form of Fig. 6 (a).

Then, shown in Figure 22 (a), form expendable film 26.Expendable film 26 has: opening 26a is used for partly exposing dielectric film 24; And a plurality of opening 26b, be used for partly exposing substrate 21.Dielectric film 24 will become aforesaid anchor portion 24a by the zone that opening 26a exposes.Can utilize with the front and be used to form expendable film 15 identical materials and identical process forms expendable film 26 with reference to Fig. 6 (b) is described.By controlling the thickness of the expendable film 26 that forms in this step, can control the initial condition distance L 2 between the float electrode 22,23 among the variable capacitor X2 of gained.

Then, shown in Figure 22 (b), form float electrode 23.Can utilize with the front and form float electrode 23 with reference to the described identical process of float electrode 13 that is used to form of Fig. 6 (c).The float electrode 23 that forms in this step is engaged to dielectric film 24 in the opening 26a of expendable film 26, and is engaged to substrate 21 in opening 26b.Note that in the drawings that in order to simplify two ends of float electrode 23 are depicted as and form by the opening 26b that fills expendable film 26 with electric conducting material.

Then, shown in Figure 22 (c), remove expendable film 26 and expendable material 25.Particularly, utilize predetermined resist remover to remove expendable film 26 and expendable material 25 by wet etch method.After the above-mentioned steps, can successfully produce variable capacitor X2.

Figure 23 is the sectional view that first of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, dielectric film 24 is formed on float electrode 22 top sides to float electrode 23; Substitute this kind configuration, dielectric film 24 can be formed on float electrode 23 top sides to float electrode 22, as shown in figure 23.

Figure 24 is the sectional view that second of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, dielectric film 24 is formed on float electrode 22 top sides to float electrode 23; Except that this configuration, dielectric film 24 also can be formed on float electrode 23 top sides to float electrode 22, as shown in figure 24.

Figure 25 is the sectional view that the 3rd of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, float electrode 23 can have shape as shown in figure 25.Float electrode 23 according to this change example has an original shape, and it comprises the part away from float electrode 22 bendings.When the float electrode 23 with this shape is driven, float electrode 23 in the face of the zone of float electrode 22 in float electrode 22 at first contact with end 23a shown in Figure 25 through dielectric film 24.It is float electrode 22 that end 23a also leaves dielectric film 24 at last.The advantage of the shape of float electrode 23 shown in Figure 25 is that this shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 26 is the sectional view that the 4th of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, float electrode 23 can have shape as shown in figure 26.Become in the example at this, float electrode 23 has an original shape, and it comprises the part away from float electrode 22 bendings; And float electrode 23 has end 23b shown in Figure 26, and the regional inner end 23b in the face of float electrode 22 contacts with float electrode 22 through dielectric film 24 in float electrode 23.When the float electrode 23 with this shape was driven, the area that is in contact with one another through dielectric film 24 between the float electrode 22,23 changed along with the driving of device, and with end 23b as basic point.Consider the low voltage operating of variable capacitor X2, float electrode 22,23 is preferred through this configuration that dielectric film 24 carries out part contact mutually.

Figure 27 is the sectional view that the 5th of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, float electrode 23 can have shape as shown in figure 27.Float electrode 23 according to this change example has an original shape, and it comprises the part towards float electrode 22 bendings.When the float electrode 23 with this shape is driven, float electrode 23 in the face of the zone of float electrode 22 in float electrode 22 at first contact with part 23c shown in Figure 27 through dielectric film 24.It is float electrode 22 that part 23c also leaves dielectric film 24 at last.The advantage of the shape of float electrode 23 shown in Figure 27 is that this shape has guaranteed that the potential part through dielectric film 24 is in contact with one another between the duration of work float electrode 22,23.

Figure 28 is the sectional view that the 6th of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, float electrode 23 can have shape as shown in figure 28.Become in the example at this, float electrode 23 has an original shape, it comprises that towards the part of float electrode 22 bendings and the part 23d shown in Figure 28 the intra-zone of facing float electrode 22 in float electrode 23 divides 23d to contact with float electrode 22 through dielectric film 24.When the float electrode 23 with this shape was driven, the area that is in contact with one another through dielectric film 24 between the float electrode 22,23 changed along with the driving of device, and with part 23d shown in Figure 28 as basic point.Consider the low voltage operating of variable capacitor X2, float electrode 22,23 is carried out mutually the partly configuration of contact through dielectric film 24 in their initial condition be preferred.

Figure 29 is the sectional view that the 7th of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, float electrode 22 can have shape as shown in figure 29.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.The advantage of the shape of float electrode 22 shown in Figure 29 is that this shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.For example utilize the resist pattern, with the float electrode 13 that becomes example at the 3rd of variable capacitor X1 in utilize the resist pattern to make the identical mode of curved surface, can obtain curved shape according to the routine float electrode 22 of this changes.

Figure 30 is the sectional view that the 8th of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 30.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings; And float electrode 23 has an original shape, and it comprises the part away from float electrode 22 bendings.The advantage of the shape of float electrode 22,23 shown in Figure 30 is that described shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 31 is the sectional view that the 9th of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 31.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.Float electrode 23 according to this change example has an original shape, it comprises that away from the part of float electrode 22 bendings and the end 23e shown in Figure 31 the regional inner end 23e in the face of float electrode 22 contacts with float electrode 22 through dielectric film 24 in float electrode 23.When the float electrode 23 with this shape was driven, float electrode 23 changed along with the driving of device with the area that float electrode 22 contacts through dielectric film 24, and with end 23e shown in Figure 31 as basic point.Consider the low voltage operating of variable capacitor X2, float electrode 22,23 is carried out mutually the partly configuration of contact through dielectric film 24 in their initial condition be preferred.

Figure 32 is the sectional view that the tenth of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 32.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings; And float electrode 23 has an original shape, and it comprises the part towards float electrode 22 bendings.The advantage of the shape of float electrode 22,23 shown in Figure 32 is that they have guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 33 is the sectional view that the 11 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 33.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.Float electrode 23 according to this change example has an original shape, it comprises that towards the part of float electrode 22 bendings and the part 23f shown in Figure 33 the intra-zone of facing float electrode 22 in float electrode 23 divides 23f to contact with float electrode 22 through dielectric film 24.When the float electrode 23 with this shape was driven, float electrode 23 changed along with the driving of device with the area that float electrode 22 contacts through dielectric film 24, and with part 23f shown in Figure 33 as basic point.Consider the low voltage operating of variable capacitor X2, the configuration that float electrode 22,23 is in contact with one another through dielectric film 24 is preferred.

Figure 34 is the sectional view that the 12 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, float electrode 22 can be configured as shape as shown in figure 34.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.The advantage of the shape of float electrode 22 shown in Figure 34 is that this shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.For example utilize the resist pattern, with the float electrode 13 that becomes example at the 3rd of variable capacitor X1 in utilize the resist pattern to make the identical mode of curved surface, can obtain curved shape according to the routine float electrode 22 of this changes.

Figure 35 is the sectional view that the 13 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 35.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings; And float electrode 23 has an original shape, and it carries out part with float electrode 22 and contacts.Consider the low voltage operating of variable capacitor X2, float electrode 22,23 is carried out the part contact each other in their initial condition configuration is preferred.

Figure 36 is the sectional view that the 14 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 36.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings; And float electrode 23 has an original shape, and it comprises the part away from float electrode 22 bendings.The advantage of the shape of float electrode 22,23 shown in Figure 36 is that described shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 37 is the sectional view that the 15 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 37.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.Float electrode 23 according to this change example has an original shape, it comprises that away from the part of float electrode 22 bendings and the end 23g shown in Figure 37 the regional inner end 23g in the face of float electrode 22 contacts with float electrode 22 through dielectric film 24 in float electrode 23.When the float electrode 23 with this shape was driven, float electrode 23 changed along with the driving of device with the area that float electrode 22 contacts through dielectric film 24, and with end 23g shown in Figure 37 as basic point.Consider the low voltage operating of variable capacitor X2, float electrode 22,23 is preferred through the configuration that dielectric film 24 carries out part contact mutually.

Figure 38 is the sectional view that the 16 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 38.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings; And float electrode 23 has an original shape, and it comprises the part towards float electrode 22 bendings.The advantage of the shape of float electrode 22,23 shown in Figure 38 is that described shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 39 is the sectional view that the 17 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.In variable capacitor X2, the shape that float electrode 22,23 can be configured as shown in figure 39.Become in the example at this, float electrode 22 has an original shape, and it is included in the part of the position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.In addition, become in the example at this, float electrode 23 has an original shape, and it comprises that towards the part of float electrode 22 bendings and the part 23h shown in Figure 39 the intra-zone of facing float electrode 22 in float electrode 23 divides 23h to contact with float electrode 22 through dielectric film 24.When the float electrode 23 with this shape was driven, float electrode 23 changed along with the driving of device with the area that float electrode 22 contacts through dielectric film 24, and with part 23h shown in Figure 39 as basic point.Consider the low voltage operating of variable capacitor X2, the configuration that float electrode 22,23 is in contact with one another through dielectric film 24 in their original shape is preferred.

Figure 40 is the sectional view that the 18 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.Float electrode 22,23 according to this change example interconnects through dielectric film 24 two positions.In other words, this change example has two anchor portion 24a.

Figure 41 is the sectional view that the 19 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.Float electrode 22,23 according to this change example interconnects through dielectric film 24 two positions.(in other words, this change example has two anchor portion 24a.) in addition, become example according to this, float electrode 22 has an original shape, its in each position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.The advantage of the shape of float electrode 22,23 shown in Figure 41 is that described shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 42 is the sectional view that the 20 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.Float electrode 22,23 according to this change example interconnects through dielectric film 24 two positions.(in other words, this change example has two anchor portion 24a.) in addition, become example according to this, float electrode 22 has an original shape, its in each position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.In addition, float electrode 23 has an original shape, and it comprises the part away from float electrode 22 bendings.The advantage of the shape of float electrode 22,23 shown in Figure 42 is that described shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 43 is the sectional view that the 21 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.Float electrode 22,23 according to this change example interconnects through dielectric film 24 two positions.(in other words, this change example has two anchor portion 24a.) in addition, become example according to this, float electrode 22 has an original shape, its in each position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings; And float electrode 23 has an original shape, and it comprises the part towards float electrode 22 bendings.The advantage of the shape of float electrode 22,23 shown in Figure 43 is that described shape has guaranteed that the potential part through dielectric film 24 contacts between the duration of work float electrode 22,23.

Figure 44 is the sectional view that the 22 of variable capacitor X2 becomes example.This figure is corresponding to Figure 19 that the cross section of variable capacitor X2 among Figure 16 is shown.Float electrode 22,23 according to this change example interconnects through dielectric film 24 two positions.(in other words, this change example has two anchor portion 24a.) in addition, become example according to this, float electrode 22 has an original shape, its in each position of the anchor portion 24a that is engaged to dielectric film 24 towards float electrode 23 bendings.Float electrode 23 according to this change example has an original shape, and it comprises the part towards float electrode 22 bendings, and this part contacts with float electrode 22 through dielectric film 24.Consider the low voltage operating of variable capacitor X2, float electrode 22,23 is carried out mutually the partly configuration of contact through dielectric film 24 in their original shape be preferred.

Figure 45 to Figure 48 illustrates the variable capacitor X3 according to third embodiment of the invention.Figure 45 is the vertical view of variable capacitor X3.Figure 46 is the unshowned vertical view of the part of variable capacitor X3.Figure 47 is the sectional view along XLVII-XLVII line among Figure 45.Figure 48 is the part amplification sectional view along XLVIII-XLVIII line among Figure 45.

Variable capacitor X3 comprises substrate 31, fixed electrode 32, float electrode 33 (not shown among Figure 46), dielectric film 34 and stopper 35.Fixed electrode 32 is formed on the substrate 31.Float electrode 33 is implemented on the substrate 31.As shown in figure 48, float electrode 33 has thickness T 3, for example is 1 to 2 μ m.Show that as clear among Figure 45 fixed electrode 32 intersects mutually with float electrode 33, part relatively each other.Relative zone for example has 10000 to 40000 μ m ²Area.Distance L 3 between fixed electrode shown in Figure 48 32 and the float electrode 33 for example is 0.5 to 2 μ m.Preferably, fixed electrode 32 and one of float electrode 33 ground connection.Dielectric film 34 is formed on fixed electrode 32 top sides to float electrode 33.Dielectric film 34 for example has the thickness of 0.1 to 0.5 μ m.Substrate 31, fixed electrode 32, float electrode 33 and dielectric film 34 by with first embodiment in their homologue (being substrate 11, fixed electrode 12, float electrode 13 and dielectric film 14) identical materials separately form.Stopper 35 penetrates float electrode 33, is engaged to float electrode 33, and is engaged to dielectric film 34.Above-mentioned stopper 35 is by dielectric material aluminium oxide (Al for example ₂O ₃), silica (SiO ₂) and silicon nitride (SiN _x) form.Be formed on the substrate 31 with fixed electrode 32 or the prescribed route pattern (not shown) that is electrically connected with float electrode 33.

In variable capacitor X3 shown in Figure 45, know demonstration as Figure 48, anchor portion 36 according to the present invention is made of the part 34a that stopper 35 and dielectric film 34 engage with stopper.Anchor portion 36 provides part to be connected between fixed electrode 32 respect to one another and float electrode 33.

According to variable capacitor X3 with above-mentioned structure, can between fixed electrode 32 and float electrode 33, produce electrostatic attraction by between fixed electrode 32 and float electrode 33, applying voltage, and by utilizing this electrostatic attraction, float electrode 33 (except that the zone that is engaged to anchor portion 36) can be pulled to fixed electrode 32, thus change as shown in figure 49 fixed electrode 32 and the volume of the clearance G 3 between the float electrode 33.(towards the pulling amount of fixed electrode 32 or pull distance in float electrode 33 in the face of being uneven on the whole zone of fixed electrode 32.The zone that is engaged to anchor portion 36 is not mobile, and float electrode 33 trends towards being pulled less amount near the zone at junction surface).The electrostatic capacitance of variable capacitor X3 changes with interstitial volume.Therefore, according to variable capacitor X3, can control electrostatic capacitance by the driving voltage (for example 0 to 20V) that control is applied between fixed electrode 32 and the float electrode 33.

In addition, according to variable capacitor X3, float electrode 33 partly is connected with fixed electrode 32 by anchor portion 36 or partly is bonded on the fixed electrode 32; This has reduced the distortion or the bending of the float electrode 33 that caused by variations in temperature in work and the inoperative.Particularly, even the coefficient of thermal expansion of substrate 31 is different from the coefficient of thermal expansion of float electrode 33, even and difference relatively large, the distortion or the bending of the float electrode 33 that is caused by variations in temperature also can diminish.Because the bending of float electrode 33 reduces in its original shape (shape in the inoperative), so in variable capacitor X3, inconsistent the reducing of the initial electrostatic electric capacity during the inoperative (for example 0.5 to 1pF).In addition, because the distortion of the float electrode 33 that is caused by variations in temperature during work and the inoperative reduces, so the inconsistent of the relation between electrostatic capacitance and the driving voltage also reduces.As mentioned above, it is inconsistent that variable capacitor X3 is very suitable for reducing the electrostatic capacitance that caused by variations in temperature.Above-mentioned variable capacitor X3 can highly precisely work.

In addition, according to variable capacitor X3, can change electrostatic capacitance significantly.As previously mentioned, in traditional variable capacitor Y, float electrode 93 must move in limited range, so that avoid the so-called phenomenon of drawing in, thereby can't change electrostatic capacitance on relative broad range.On the contrary,, shown in Figure 49 (c) and Figure 49 (d), float electrode 33 is contacted with fixed electrode 32 parts through dielectric film 34 according to variable capacitor X3 provided by the invention, and the area of further control section contact.Therefore, according to variable capacitor X3, can be with the interstitial volume between fixed electrode 32 and the float electrode 33 from the initial condition shown in Figure 49 (a), change to significantly that the contact area through dielectric film 34 reaches peaked state (for example state shown in Figure 49 (d)) between fixed electrode 32 and the float electrode 33.In addition, according to variable capacitor X3, float electrode 33 is not through the zone of anchor portion 36 in the face of fixed electrode 32.In other words, less than localized capacitance device structure through the interelectrode distance of anchor portion 36 immutable (thereby electrostatic capacitance is fixed).Have the fixedly localized capacitance device structure of electrostatic capacitance if variable capacitor comprises, then the minimum electrostatic capacitance of whole variable capacitor can't be less than this fixing electrostatic capacitance.On the contrary, the variable capacitor X3 that does not comprise any localized capacitance device structure (it has fixedly electrostatic capacitance) does not have the restriction of this minimum electrostatic capacitance for whole variable capacitor.Therefore, in variable capacitor X3, be easy to the minimum electrostatic capacitance that provides less.As mentioned above, according to variable capacitor X3, can change the interstitial volume between fixed electrode 32 and the float electrode 33 significantly, and can set a smaller value to minimum electrostatic capacitance, this is because the unfixing interelectrode distance through anchor portion 36 of this structure.Therefore, variable capacitor X3 can provide big electrostatic capacitance change amount or rate of change.

Figure 50 illustrates the manufacture method of variable capacitor X3 with a series of sectional views that correspond respectively to cross section shown in Figure 47.This method utilizes so-called MEMS technology to make variable capacitor X3.

In the manufacturing of variable capacitor X3, at first shown in Figure 50 (a), fixed electrode 32 and dielectric film 34 are formed on the substrate 31 stackedly.Can utilize with reference to the described identical process of fixed electrode 12 and dielectric film 14 that is used to form of Fig. 6 (a), form fixed electrode 32 and dielectric film 34.

Then, shown in Figure 50 (b), form expendable film 37.Expendable film 37 has: opening 37a is used for partly exposing dielectric film 34; And a plurality of opening 37b, be used for partly exposing substrate 31.The part 34a that dielectric film 34 exposes by opening 37a will become the part of aforesaid anchor portion 36.Can utilize with the front and be used to form expendable film 15 identical materials and identical process forms expendable film 37 with reference to Fig. 6 (b) is described.By controlling the thickness of the expendable film 37 that forms in this step, can control the initial condition distance L 3 between the fixed electrode 32 and float electrode 33 among the variable capacitor X3 of gained.

Then, shown in Figure 50 (c), form float electrode 33.Float electrode 33 has the opening 33a that is communicated with the opening 37a of expendable film 37.For example form float electrode 33 by following steps: at first form the aluminium film by sputtering method on expendable film 37 and among opening 37a, the 37b, the mask through having predetermined resist pattern comes etching aluminium film then.Note that in the drawings that in order to simplify two ends of float electrode 33 are depicted as that opening 37b in the expendable film 37 forms by filling with electric conducting material.

Then, shown in Figure 50 (d), form stopper 35.For example, fill the through hole that provides by opening 33a, 37a with dielectric material thus, can form stopper 35 by sputtering method.

, with predetermined resist remover carry out wet etching, to remove expendable film 37 thereafter.After the above-mentioned steps, can successfully produce variable capacitor X3.

Figure 51 is the sectional view that first of variable capacitor X3 becomes example.This figure is corresponding to Figure 48 that the cross section of variable capacitor X3 among Figure 45 is shown.Shown in Figure 51, in variable capacitor X3, stopper 35 penetrable dielectric films 34 are to be engaged to fixed electrode 32.In this became example, stopper 35 constituted anchor portion 36, and this anchor portion 36 provides part to be connected between fixed electrode 32 respect to one another and float electrode 33.Utilize and the identical method of above-mentioned manufacturing variable capacitor X3, and the additional step after the step shown in Figure 50 (a), promptly in dielectric film 34, make the opening of will pack into according to the routine stopper 35 of this change, can produce this change example.

Figure 52 is the sectional view that second of variable capacitor X3 becomes example.This figure is corresponding to Figure 48 that the cross section of variable capacitor X3 among Figure 45 is shown.In variable capacitor X3, dielectric film 34 is formed on fixed electrode 32 top sides to float electrode 33; Substitute this configuration, dielectric film 34 can be formed on float electrode 33 top sides to fixed electrode 32, shown in Figure 52.In this became example, stopper 35 constituted anchor portion 36, and this anchor portion 36 provides part to be connected between fixed electrode 32 respect to one another and float electrode 33.Utilize and the identical method of above-mentioned manufacturing variable capacitor X3, and for example following the variation, can produce this change example.Particularly, have opening 37a and cover the step of the expendable film 37 of fixed electrode 32 with formation, and the step that on expendable film 37, forms the dielectric film 34 with prodefined opening (it is communicated with opening 37a) thereafter, be substituted in and form the step that dielectric film 34 forms expendable film 37 afterwards.

Shown in Figure 53, can have the 35a of lid according to the stopper 35 of variable capacitor X3 (comprise first become example and second become routine).Shown lid 35a helps to guarantee the engagement relationship between float electrode 33 and the stopper 35.

Can be similar to the float electrode 13 of one of change example according to Figure 11 and variable capacitor X1 shown in Figure 14 according to the float electrode 33 of variable capacitor X3 (comprise first become example and second become routine), promptly can have the original shape that comprises sweep.Perhaps, can be similar to the float electrode 13 of one of change example according to Figure 13 and variable capacitor X1 shown in Figure 15 according to the float electrode 33 of variable capacitor X3 (comprise first become example and second become routine), promptly can have an original shape, it comprises sweep and has through dielectric film and the contacted part of fixed electrode.

Figure 54 and Figure 55 illustrate the variable capacitor X4 according to fourth embodiment of the invention.Figure 54 is the sectional view of variable capacitor X4, corresponding to the Figure 47 in the cross section that above-mentioned variable capacitor X3 is shown.Figure 55 is the part amplification sectional view of variable capacitor X4, corresponding to the Figure 48 in the cross section that above-mentioned variable capacitor X3 is shown.

Variable capacitor X4 comprises substrate 41, fixed electrode 42, float electrode 43, dielectric film 44 and stopper 45.Fixed electrode 42 is formed on the substrate 41.Float electrode 43 is implemented on the substrate 41.Fixed electrode 42 intersects mutually with float electrode 43, and part relatively each other.Distance L 4 between fixed electrode shown in Figure 55 42 and the float electrode 43 for example is 0.5 to 2 μ m.Preferably, fixed electrode 42 and one of float electrode 43 ground connection.Dielectric film 44 is formed on float electrode 43 top sides to fixed electrode 42.Stopper 45 penetrates fixed electrode 42, is engaged to fixed electrode 42, and is engaged to dielectric film 44.Be formed on the substrate 41 with fixed electrode 42 or the prescribed route pattern (not shown) that is electrically connected with float electrode 43.Substrate 41, fixed electrode 42, float electrode 43 and dielectric film 44 by with first embodiment in their homologue (being substrate 11, fixed electrode 12, float electrode 13 and dielectric film 14) identical materials separately form.Stopper 45 by with the 3rd embodiment in stopper 35 identical materials form.

In the variable capacitor X4 shown in Figure 54, know demonstration as Figure 55, anchor portion 46 according to the present invention is made of the part 44a that stopper 45 and dielectric film 44 engage with stopper.Anchor portion 46 provides part to be connected between fixed electrode 42 respect to one another and float electrode 43.

According to variable capacitor X4 with above-mentioned structure, described as the front for variable capacitor X3, be applied to driving voltage (for example 0 to 20V) between fixed electrode 42 and the float electrode 43 by control, can control electrostatic capacitance.In addition, according to variable capacitor X4, float electrode 43 partly is connected with fixed electrode 42 by anchor portion 46 or partly is bonded on the fixed electrode 42, thereby has reduced the distortion or the bending of the float electrode 43 that caused by variations in temperature during work and the inoperative.Described variable capacitor X4 can highly precisely work as variable capacitor X3.In addition, according to variable capacitor X4, can change the interstitial volume between fixed electrode 42 and the float electrode 43 significantly, and can set a smaller value to minimum electrostatic capacitance, this is because the unfixing interelectrode distance through anchor portion 46 of this structure.Therefore, as variable capacitor X3, variable capacitor X4 can provide big electrostatic capacitance change amount or rate of change.

Figure 56 illustrates the manufacture method of variable capacitor X4 with a series of sectional views that correspond respectively to cross section shown in Figure 55.This method utilizes so-called MEMS technology to make variable capacitor X4.

In the manufacturing of variable capacitor X4, at first shown in Figure 56 (a), fixed electrode 42 and expendable film 47 are formed on the substrate 41 stackedly.Fixed electrode 42 has opening 42a, and expendable film 47 has: the opening 47a that is communicated with opening 42a, and the unshowned opening that is used for partly exposing substrate 41.For example can form fixed electrode 42 by following steps: at first form the aluminium film to cover float electrode 43 by sputtering method on substrate 41, the mask through having predetermined resist pattern comes etching aluminium film then.For example can form expendable film 47 by following steps: at first form the film of expendable material on substrate 41 by sputtering method, the mask through having predetermined resist pattern comes this film of etching then.By the thickness of control expendable film 47, can control the initial condition distance L 4 between the fixed electrode 42 and float electrode 43 among the variable capacitor X4 of gained.

Then, shown in Figure 56 (b), form stopper 45.For example, fill the through hole that provides by opening 42a, 47a with dielectric material thus, can form stopper 45 by sputtering method.

Then, shown in Figure 56 (c), form dielectric film 44.For example form dielectric film 44 by following steps: form the film of being scheduled to dielectric material in the precalculated position by sputtering method, the mask through having predetermined resist pattern comes this film of etching then.The dielectric film 44 of Huo Deing is engaged to stopper 45 by this way.

Then, shown in Figure 56 (d), form float electrode 43.For example form float electrode 43 by following steps: forming the aluminium film by sputtering method on the expendable film 47 and in above-mentioned expendable film 47 unshowned openings, the mask through having predetermined resist pattern comes this film of etching then.

, with predetermined resist remover carry out wet etching, to remove expendable film 47 thereafter.After the above-mentioned steps, can successfully produce variable capacitor X4.

Figure 57 is the sectional view that first of variable capacitor X4 becomes example.This figure is corresponding to Figure 55 that the cross section of variable capacitor X4 among Figure 54 is shown.In variable capacitor X4, stopper 45 penetrable dielectric films 44 are to be engaged to float electrode 43, shown in Figure 57.In this became example, stopper 45 constituted anchor portion 46, and this anchor portion 46 provides part to be connected between fixed electrode 42 respect to one another and float electrode 43.Utilize and the identical method of above-mentioned manufacturing variable capacitor X4, and for example following the variation, can produce this change example.Particularly, be used in the step that forms dielectric film 44 on the expendable film 47 with prodefined opening (it is communicated with the opening 47a of expendable film 47), and form step thereafter according to the stopper 45 that penetrates fixed electrode 42, expendable film 47 and dielectric film 44 of this change example, replace and form stopper 45, form the step of dielectric film 44 then.

Figure 58 is the sectional view that second of variable capacitor X4 becomes example.This figure is corresponding to Figure 55 that the cross section of variable capacitor X4 among Figure 54 is shown.In variable capacitor X4, dielectric film 44 is formed on float electrode 43 top sides to fixed electrode 42; Substitute this configuration, dielectric film 44 can be formed on fixed electrode 42 top sides to float electrode 43, shown in Figure 58.In this became example, stopper 45 constituted anchor portion 46, and this anchor portion 46 provides part to be connected between fixed electrode 42 respect to one another and float electrode 43.Utilize and the identical method of above-mentioned manufacturing variable capacitor X4, and for example following the variation, can produce this change example.Particularly, the step that has the fixed electrode 42 of opening 42a with formation, and the step that on fixed electrode 42, forms the dielectric film 44 with prodefined opening (it is communicated with opening 42a) thereafter, replace formation stopper 45, form the step of dielectric film 44 then.

Can be similar to the float electrode 13 of one of change example according to Figure 11 and variable capacitor X1 shown in Figure 14 according to the float electrode 43 of variable capacitor X4 (comprise first become example and second become routine), promptly can have the original shape that comprises sweep.Perhaps, can be similar to the float electrode 13 of one of change example according to Figure 13 and variable capacitor X1 shown in Figure 15 according to the float electrode 43 of variable capacitor X4 (comprise first become example and second become routine), promptly can have an original shape, it comprises sweep and has through dielectric film and the contacted part of fixed electrode.

Figure 59 and Figure 60 illustrate the variable capacitor X5 according to fifth embodiment of the invention.Figure 59 is the sectional view of variable capacitor X5, corresponding to the Figure 47 in the cross section that above-mentioned variable capacitor X3 is shown.Figure 60 is the part amplification sectional view of variable capacitor X5, corresponding to Figure 48 of the part amplification sectional view that above-mentioned variable capacitor X3 is shown.

Variable capacitor X5 comprises substrate 51, fixed electrode 52, float electrode 53, dielectric film 54 and stopper 55.Fixed electrode 52 is formed on the substrate 51.Float electrode 53 is implemented on the substrate 51.Fixed electrode 52 intersects mutually with float electrode 53, and part relatively each other.Distance L 5 between fixed electrode shown in Figure 60 52 and the float electrode 53 for example is 0.5 to 2 μ m.Preferably, fixed electrode 52 and one of float electrode 53 ground connection.Dielectric film 54 is formed on float electrode 53 top sides to fixed electrode 52.Stopper 55 penetrates fixed electrode 52, and is engaged to fixed electrode 52; Penetrate dielectric film 54 and float electrode 53 in addition, and be engaged to float electrode 53.Be formed on the substrate 51 with fixed electrode 52 or the prescribed route pattern (not shown) that is electrically connected with float electrode 53.Substrate 51, fixed electrode 52, float electrode 53 and dielectric film 54 by with first embodiment in their homologue (being substrate 11, fixed electrode 12, float electrode 13 and dielectric film 14) identical materials separately form.Stopper 55 by with the 3rd embodiment in stopper 35 identical materials form.

In the variable capacitor X5 shown in Figure 59, anchor portion 56 according to the present invention is made of stopper 55.Anchor portion 56 provides part to be connected between fixed electrode 52 respect to one another and float electrode 53.

According to variable capacitor X5 with above-mentioned structure, described as the front for variable capacitor X3, be applied to driving voltage (for example 0 to 20V) between fixed electrode 52 and the float electrode 53 by control, can control electrostatic capacitance.In addition, according to variable capacitor X5, float electrode 53 partly is connected with fixed electrode 52 by anchor portion 56 or partly is bonded on the fixed electrode 52, thereby has reduced the distortion or the bending of the float electrode 53 that caused by variations in temperature during work and the inoperative.Described variable capacitor X5 can highly precisely work as variable capacitor X3.In addition, according to variable capacitor X5, can change the interstitial volume between fixed electrode 52 and the float electrode 53 significantly, and can set a smaller value to minimum electrostatic capacitance, this is because the unfixing interelectrode distance through anchor portion 56 of this structure.Therefore, as variable capacitor X3, variable capacitor X5 can provide big electrostatic capacitance change amount or rate of change.

Figure 61 illustrates the manufacture method of variable capacitor X5 with a series of sectional views that correspond respectively to cross section shown in Figure 60.This method utilizes so-called MEMS technology to make variable capacitor X5.

In the manufacturing of variable capacitor X5, at first shown in Figure 61 (a), fixed electrode 52 and expendable film 57 are formed on the substrate 51 stackedly.Fixed electrode 52 has opening 52a, and expendable film 57 has: the opening 57a that is communicated with opening 52a, and the unshowned opening that is used for partly exposing substrate 51.By with the front with reference to the described identical process of fixed electrode 42 and expendable film 47 that is used to form of Figure 56 (a), can form fixed electrode 52 and expendable film 57.

Then, shown in Figure 61 (b), form dielectric film 54, it has the opening 54a that is communicated with opening 57a.For example form dielectric film 54 by following steps: form the film of being scheduled to dielectric material in the precalculated position by sputtering method, the mask through having predetermined resist pattern comes this film of etching then.

Then, shown in Figure 61 (c), form float electrode 53, it has the opening 53a that is communicated with opening 54a.For example form float electrode 53 by following steps: forming the aluminium film by sputtering method on dielectric film 54, the expendable film 57 and in above-mentioned expendable film 57 unshowned openings, the mask through having predetermined resist pattern comes etching aluminium film then.

Then, shown in Figure 61 (d), form stopper 55.For example, fill the through hole that provides by opening 52a, 53a, 54a and 57a with dielectric material thus, can form stopper 55 by sputtering method.

, with predetermined resist remover carry out wet etching, to remove expendable film 57 thereafter.Follow after the above-mentioned steps, can successfully produce variable capacitor X5.

Figure 62 is the sectional view of the change example of variable capacitor X5.This figure is corresponding to Figure 60 that the cross section of variable capacitor X5 among Figure 59 is shown.In variable capacitor X5, dielectric film 54 is formed on float electrode 53 top sides to fixed electrode 52; Substitute this configuration, dielectric film 54 can be formed on fixed electrode 52 top sides to float electrode 53.Utilize and the identical method of above-mentioned manufacturing variable capacitor X5, and for example following the variation, can produce this change example.Particularly, with the step that forms fixed electrode 52, and the step that forms dielectric film 54 and expendable film 57 thereafter successively, replace and form fixed electrode 52, form the step of expendable film 57 and dielectric film 54 successively then.

According to the variable capacitor X5 that comprises above-mentioned change example, stopper 55 can have the lid 55a shown in Figure 63.Shown lid 55a helps to guarantee the engagement relationship between float electrode 53 and the stopper 55.

Can be similar to the float electrode 13 of one of change example according to Figure 11 and variable capacitor X1 shown in Figure 14 according to the float electrode 53 of variable capacitor X5 (comprising above-mentioned change example), promptly can have the original shape that comprises sweep.Perhaps, can be similar to the float electrode 13 of one of change example according to Figure 13 and variable capacitor X1 shown in Figure 15 according to the float electrode 53 of variable capacitor X5 (comprising above-mentioned change example), promptly can have an original shape, it comprises sweep and has through dielectric film and the contacted part of fixed electrode.

Figure 64 to Figure 67 illustrates the variable capacitor X6 according to sixth embodiment of the invention.Figure 64 is the vertical view of variable capacitor X6.Figure 65 is the unshowned vertical view of the part of variable capacitor X6.Figure 66 is the sectional view along LXVI-LXVI line among Figure 64.Figure 67 is the part amplification sectional view along LXVII-LXVII line among Figure 64.

Variable capacitor X6 comprises substrate 61, float electrode 62, float electrode 63 (not shown among Figure 65), dielectric film 64 and stopper 65.Substrate 61 has groove 61a.Float electrode 62 has two ends that are engaged to substrate 61, and extends above groove 61a.Float electrode 63 is implemented on the substrate 61.Shown in Figure 67, float electrode 63 has thickness T 6, for example is 1 to 2 μ m.Show that as clear among Figure 64 float electrode 62,63 is intersected mutually, part relatively each other.Relative zone for example has 10000 to 40000 μ m ²Area.Distance L 6 between the float electrode shown in Figure 67 62 and 63 for example is 0.5 to 2 μ m.Preferably, one of float electrode 62,63 ground connection.Dielectric film 64 is formed on float electrode 62 top sides to float electrode 63.Dielectric film 64 for example has the thickness of 0.1 to 0.5 μ m.Substrate 61, float electrode 62,63 and dielectric film 64 by with second embodiment in their homologue (being substrate 21, float electrode 22,23 and dielectric film 24) identical materials separately form.Stopper 65 penetrates float electrode 63, is engaged to float electrode 63, and is engaged to dielectric film 64.Described stopper 65 is by dielectric material aluminium oxide (Al for example ₂O ₃), silica (SiO ₂) and silicon nitride (SiN _x) form.Be formed on the substrate 61 with float electrode 62 or the prescribed route pattern (not shown) that is electrically connected with float electrode 63.

In the variable capacitor X6 shown in Figure 64, show that as Figure 67 is clear anchor portion 66 according to the present invention is made of with stopper engaging portion 64a stopper 65 and dielectric film 64.Anchor portion 66 provides part to connect between float electrode 62,63 respect to one another.

According to variable capacitor X6 with above-mentioned structure, can between float electrode 62,63, produce electrostatic attraction by between float electrode 62,63, applying voltage, and by utilizing this electrostatic attraction, float electrode 62,63 (except that float electrode 62,63 is engaged to the zone of anchor portion 66) can be furthered each other, thus the volume of the clearance G 6 between the float electrode 62,63 of change shown in Figure 68.The electrostatic capacitance of variable capacitor X6 changes with interstitial volume.Therefore, according to variable capacitor X6, can control electrostatic capacitance by the driving voltage (for example 0 to 20V) that control is applied between the float electrode 62,63.

In addition, according to variable capacitor X6, float electrode 62,63 partly connects each other by anchor portion 66 or engages; This has reduced the distortion or the bending of the float electrode 62,63 that caused by variations in temperature in work and the inoperative.Because the bending of float electrode 62,63 reduces in its original shape (shape in the inoperative), so in variable capacitor X6, inconsistent the reducing of the initial electrostatic electric capacity during the inoperative (for example 0.5 to 1pF).In addition, because the distortion of the float electrode 62,63 that is caused by variations in temperature during work and the inoperative reduces, so the inconsistent of the relation between electrostatic capacitance and the driving voltage also reduces.As mentioned above, it is inconsistent that variable capacitor X6 is very suitable for reducing the electrostatic capacitance that caused by variations in temperature.Above-mentioned variable capacitor X6 can highly precisely work.

In addition, according to variable capacitor X6, can change electrostatic capacitance significantly.Illustrate that as the front in traditional variable capacitor Y, float electrode 93 must move in limited range,, thereby can't on relative broad range, change electrostatic capacitance so that avoid the so-called phenomenon of drawing in.On the contrary,, shown in Figure 68 (c) and Figure 68 (d), can make float electrode 62,63 through dielectric film 64 part contact each other according to variable capacitor X6 provided by the invention, and the area of further control section contact.Therefore, according to variable capacitor X6, can be with the interstitial volume between the float electrode 62,63 from the initial condition shown in Figure 68 (a), change to significantly that the contact area through dielectric film 64 reaches peaked state (for example state shown in Figure 68 (d)) between the float electrode 62,63.In addition, according to variable capacitor X6, the zone that float electrode 62,63 does not have through anchor portion 66 faces with each other.In other words, not through the localized capacitance device structure of the interelectrode distance constant (thereby electrostatic capacitance is fixed) of anchor portion 66.Have the fixedly localized capacitance device structure of electrostatic capacitance if variable capacitor comprises, then the minimum electrostatic capacitance of whole variable capacitor can't be less than this fixing electrostatic capacitance.On the contrary, the variable capacitor X6 that does not comprise any localized capacitance device structure (it has fixedly electrostatic capacitance) does not have the restriction of this minimum electrostatic capacitance for whole variable capacitor.Therefore, in variable capacitor X6, be easy to set less minimum electrostatic capacitance.As mentioned above, according to variable capacitor X6, can change the interstitial volume between the float electrode 62,63 significantly, and can set a smaller value to minimum electrostatic capacitance, this is because the unfixing interelectrode distance through anchor portion 66 of this structure.Therefore, variable capacitor X6 can provide big electrostatic capacitance change amount or rate of change.

Figure 69 and Figure 70 illustrate the manufacture method of variable capacitor X6 with a series of sectional views that correspond respectively to cross section shown in Figure 66.This method utilizes so-called MEMS technology to make variable capacitor X6.

In the manufacturing of variable capacitor X6, at first, preparation has the substrate 61 of groove 61a shown in Figure 69 (a).Particularly, carry out with reference to the identical step of the described preparation substrate of Figure 21 (a) 21.

Then, shown in Figure 69 (b), fill the groove 61a of substrate 61 with expendable material 67.Particularly, carry out and fill expendable material 67 with reference to the described identical step of Figure 21 (b).

Then, shown in Figure 69 (c), on substrate 61, form float electrode 62 and dielectric film 64 stackedly.Can utilize and form float electrode 62 and dielectric film 64 with reference to the described identical process of fixed electrode 12 and dielectric film 14 that is used to form of Fig. 6 (a).

Then, shown in Figure 70 (a), form expendable film 68.Expendable film 68 has: opening 68a is used for partly exposing dielectric film 64; And a plurality of opening 68b, be used for partly exposing substrate 61.The regional 64a that dielectric film 64 exposes by opening 68a will become the part of aforesaid anchor portion 66a.Can utilize with the front and be used to form expendable film 15 identical materials and identical process forms expendable film 68 with reference to Fig. 6 (b) is described.By controlling the thickness of the expendable film 68 that forms in this step, can control the initial condition distance L 6 between the float electrode 62,63 among the variable capacitor X6 of gained.

Then, shown in Figure 70 (b), form float electrode 63.Float electrode 63 has the opening 63a that is communicated with the opening 68a of expendable film 68.Can utilize with preceding and form float electrode 63 with reference to the described identical process of float electrode 33 that is used to form of Figure 50 (c).Note that the opening 68b that two ends of float electrode 63 are depicted as by filling in the expendable film 68 with electric conducting material forms in the drawings in order to simplify.

Then, shown in Figure 70 (c), form stopper 65.For example, fill the through hole that provides by opening 63a, 68a with dielectric material thus, can form stopper 65 by sputtering method.

, utilize predetermined resist remover carry out wet etching, to remove expendable film 68 and expendable material 67 thereafter.After the above-mentioned steps, can successfully produce variable capacitor X6.

Figure 71 is the sectional view that first of variable capacitor X6 becomes example.This figure is corresponding to Figure 67 that the cross section of variable capacitor X6 among Figure 64 is shown.Shown in Figure 71, in variable capacitor X6, stopper 65 penetrable dielectric films 64 are to be engaged to float electrode 62.Become in the example at this, stopper 65 constitutes anchor portion 66, and this anchor portion 66 provides part to connect between float electrode 62,63 respect to one another.Utilize the method for above-mentioned manufacturing variable capacitor X6, and the additional step after the step shown in Figure 69 (c), promptly in dielectric film 64, make the opening of will pack into according to the routine stopper 65 of this change, can produce this change example.

Figure 72 is the sectional view that second of variable capacitor X6 becomes example.This figure is corresponding to Figure 67 that the cross section of variable capacitor X6 among Figure 64 is shown.In variable capacitor X6, dielectric film 64 is formed on float electrode 62 top sides to float electrode 63; Substitute this configuration, dielectric film 64 can be formed on float electrode 63 top sides to float electrode 62, shown in Figure 72.Become in the example at this, stopper 65 constitutes anchor portion 66, and this anchor portion 66 provides part to connect between float electrode 62,63 respect to one another.Utilize and the identical method of above-mentioned manufacturing variable capacitor X6, and for example following the variation, can produce this change example.Particularly, have opening 68a and cover the step of the expendable film 68 of float electrode 62 with formation, and the step that on expendable film 68, forms the dielectric film 64 with prodefined opening (it is communicated with opening 68a) thereafter, be substituted in and form the step that dielectric film 64 forms expendable film 68 afterwards.

Shown in Figure 73, can have the 65a of lid according to the stopper 65 of variable capacitor X6 (comprise first become example and second become routine).Shown lid 65a helps to guarantee the engagement relationship between float electrode 63 and the stopper 65.

Can be similar to the float electrode 22,23 of one of change example according to Figure 25, Figure 27, Figure 29, Figure 30, Figure 32, Figure 34, Figure 36 and variable capacitor X2 shown in Figure 38 according to the float electrode 62,63 of variable capacitor X6 (comprise first become example and second become routine), promptly can have the original shape that comprises sweep.Perhaps, can be similar to the float electrode 22,23 of one of change example according to Figure 26, Figure 28, Figure 31, Figure 33, Figure 35, Figure 37 and variable capacitor X2 shown in Figure 39 according to the float electrode 62,63 of variable capacitor X6 (comprise first become example and second become routine), promptly can have an original shape, it comprises sweep and has through dielectric film and the contacted part of fixed electrode.Moreover, can be similar to the float electrode 22,23 of one of change example according to Figure 40 variable capacitor X2 extremely shown in Figure 44 according to the float electrode 62,63 of variable capacitor X6 (comprise first become example and second become example), promptly can interconnect by anchor portion 66 respectively, and have and the similar original shape of the float electrode 22,23 of Figure 40 to the change example shown in Figure 44 two positions.

Figure 74 and Figure 75 illustrate the variable capacitor X7 according to seventh embodiment of the invention.Figure 74 is the sectional view of variable capacitor X7, corresponding to the Figure 66 in the cross section that aforementioned variable capacitor X6 is shown.Figure 75 is the part amplification sectional view of variable capacitor X7, corresponding to Figure 67 of the part amplification sectional view that variable capacitor X6 is shown.

Variable capacitor X7 comprises substrate 71, float electrode 72,73, dielectric film 74 and stopper 75.Substrate 71 has groove 71a.Float electrode 72 has two ends that are engaged to substrate 71, and extends above groove 71a.Float electrode 73 is implemented on the substrate 71. Float electrode 72,73 is intersected mutually, and part relatively each other.Distance L 7 between the float electrode shown in Figure 75 72,73 for example is 0.5 to 2 μ m.Preferably, one of float electrode 72,73 ground connection.Dielectric film 74 is formed on float electrode 73 top sides to float electrode 72.Stopper 75 penetrates float electrode 72, is engaged to float electrode 72, and is engaged to dielectric film 74.Be formed on the substrate 71 with float electrode 72 or the prescribed route pattern (not shown) that is electrically connected with float electrode 73.Substrate 71, float electrode 72, float electrode 73 and dielectric film 74 by with second embodiment in their homologue (being substrate 21, float electrode 22,23 and dielectric film 24) identical materials separately form.Stopper 75 by with the 6th embodiment in stopper 65 identical materials form.

In the variable capacitor X7 shown in Figure 74, show that as Figure 75 is clear anchor portion 76 according to the present invention is made of with stopper engaging portion 74a stopper 75 and dielectric film 74.Anchor portion 76 provides part to connect between float electrode 72,73 respect to one another.

According to variable capacitor X7 with above-mentioned structure, described as the front for variable capacitor X6, be applied to driving voltage (for example 0 to 20V) between the float electrode 72,73 by control, can control electrostatic capacitance.In addition, according to variable capacitor X7, two float electrodes 72,73 partly connect each other by anchor portion 76 or engage, thereby have reduced the distortion or the bending of the float electrode 72,73 that caused by variations in temperature during work and the inoperative.Described variable capacitor X7 can highly precisely work as variable capacitor X6.In addition, according to variable capacitor X7, can change the interstitial volume between the float electrode 72,73 significantly, and be easy to minimum electrostatic capacitance is set a smaller value, this is because this capacitor does not comprise through the fixing structure of the interelectrode distance of anchor portion 76.Therefore, as variable capacitor X6, variable capacitor X7 can provide big electrostatic capacitance change amount or rate of change.

Figure 76 and Figure 77 illustrate the manufacture method of variable capacitor X7 with a series of sectional views that correspond respectively to cross section shown in Figure 75.This method utilizes so-called MEMS technology to make variable capacitor X7.

In the manufacturing of variable capacitor X7, at first shown in Figure 76 (a), with the groove 71a in the expendable material 77 filling substrates 71.Particularly, carry out and fill expendable material 77 with reference to the described identical step of Figure 21 (b).

Then, shown in Figure 76 (b), on the substrate 71, promptly on expendable material 77, form float electrode 72.Float electrode 72 has opening 72a.Can utilize and form float electrode 72 with reference to the described identical process of fixed electrode 42 that is used to form of Figure 56 (a).

Then, shown in Figure 76 (c), form expendable film 78.Expendable film 78 has the opening 78a that is communicated with opening 72a.Can utilize and form expendable film 78 with reference to the described identical process of expendable film 47 that is used to form of Figure 56 (a).By controlling the thickness of the expendable film 78 that forms in this step, can control the initial condition distance L 7 between the float electrode 72,73 among the variable capacitor X7 of gained.

Then, shown in Figure 77 (a), form stopper 75.For example, fill the through hole that provides by opening 72a, 78a with dielectric material thus, can form stopper 75 by sputtering method.

Then, shown in Figure 77 (b), form dielectric film 74.Can utilize and form dielectric film 74 with reference to the described identical process of dielectric film 44 that is used to form of Figure 56 (c).The dielectric film 74 of Huo Deing is engaged to stopper 75 in this way.

Then, shown in Figure 77 (c), form float electrode 73.Can utilize and form float electrode 73 with reference to the described identical process of float electrode 43 that is used to form of Figure 56 (d).

, utilize predetermined resist remover carry out wet etching, to remove expendable film 78 and expendable material 77 thereafter.After the above-mentioned steps, can successfully produce variable capacitor X7.

Figure 78 is the sectional view that first of variable capacitor X7 becomes example.This figure is corresponding to Figure 75 that the cross section of variable capacitor X7 among Figure 74 is shown.Shown in Figure 78, in variable capacitor X7, stopper 75 penetrable dielectric films 74 are to be engaged to float electrode 73.Become in the example at this, stopper 75 constitutes anchor portion 76, and this anchor portion 76 provides part to connect between float electrode 72,73 respect to one another.Utilize and the identical method of above-mentioned manufacturing variable capacitor X7, and for example following the variation, can produce this change example.Particularly, be used in the step that forms dielectric film 74 on the expendable film 78 with prodefined opening (it is communicated with the opening 78a of expendable film 78), and form step thereafter according to the stopper 75 that penetrates float electrode 72, expendable film 78 and dielectric film 74 of this change example, be substituted in and form the step that forms dielectric film 74 after the stopper 75.

Figure 79 is the sectional view that second of variable capacitor X7 becomes example.This figure is corresponding to Figure 75 that the cross section of variable capacitor X7 among Figure 74 is shown.In variable capacitor X7, dielectric film 74 is formed on float electrode 73 top sides to float electrode 72; Substitute this configuration, dielectric film 74 can be formed on float electrode 72 top sides to float electrode 73, shown in Figure 79.Become in the example at this, stopper 75 constitutes anchor portion 76, and this anchor portion 76 provides part to connect between float electrode 72,73 respect to one another.Utilize and the identical method of above-mentioned manufacturing variable capacitor X7, and for example following the variation, can produce this change example.Particularly, with the step that forms float electrode 72 with opening 72a, and the step that forms the dielectric film 74 with prodefined opening (it is communicated with opening 72a) thereafter, replace the step that forms stopper 75 and reach the step that forms dielectric film 74 thereafter.

Can be similar to the float electrode 22,23 of one of change example according to Figure 25, Figure 27, Figure 29, Figure 30, Figure 32, Figure 34, Figure 36 and variable capacitor X2 shown in Figure 38 according to the float electrode 72,73 of variable capacitor X7 (comprise first become example and second become routine), promptly can have the original shape that comprises sweep.Perhaps, can be similar to the float electrode 22,23 of one of change example according to Figure 26, Figure 28, Figure 31, Figure 33, Figure 35, Figure 37 and variable capacitor X2 shown in Figure 39 according to the float electrode 72,73 of variable capacitor X7 (comprise first become example and second become routine), promptly can have an original shape, it comprises sweep and has the part that contacts with each other through dielectric film.Moreover, can be similar to the float electrode 22,23 of one of change example according to Figure 40 variable capacitor X2 extremely shown in Figure 44 according to the float electrode 72,73 of variable capacitor X7 (comprise first become example and second become example), promptly can interconnect by anchor portion 76 respectively, and have and the similar original shape of the float electrode 22,23 of Figure 40 to the change example shown in Figure 44 two positions.

Figure 80 and Figure 81 illustrate the variable capacitor X8 according to eighth embodiment of the invention.Figure 80 is the sectional view of variable capacitor X8, corresponding to the Figure 66 in the cross section that aforementioned variable capacitor X6 is shown.Figure 81 is the part amplification sectional view of variable capacitor X8, corresponding to Figure 67 of the part amplification sectional view that variable capacitor X6 is shown.

Variable capacitor X8 comprises substrate 81, float electrode 82,83, dielectric film 84 and stopper 85.Substrate 81 has groove 81a.Float electrode 82 has two ends that are engaged to substrate 81, and extends above groove 81a.Float electrode 83 is implemented on the substrate 81. Float electrode 82,83 is intersected mutually, and part relatively each other.Distance L 8 between the float electrode shown in Figure 81 82,83 for example is 0.5 to 2 μ m.Preferably, one of float electrode 82,83 ground connection.Stopper 85 penetrates float electrode 82, and is engaged to float electrode 82; And penetrate dielectric film 84 and float electrode 83, and be engaged to float electrode 83.Be formed on the substrate 81 with float electrode 82 or the prescribed route pattern (not shown) that is electrically connected with float electrode 83.Substrate 81, float electrode 82,83 and dielectric film 84 by with second embodiment in their homologue (being substrate 21, float electrode 22,23 and dielectric film 24) identical materials separately form.Stopper 85 by with the 6th embodiment in stopper 65 identical materials form.

In the variable capacitor X8 shown in Figure 80, anchor portion 86 according to the present invention is made of stopper 85.Anchor portion 86 provides part to connect between float electrode 82,83 respect to one another.

According to variable capacitor X8 with above-mentioned structure, in aforesaid variable capacitor X6, be applied to driving voltage (for example 0 to 20V) between the float electrode 82,83 by control, can control electrostatic capacitance.In addition, according to variable capacitor X8, float electrode 82,83 partly connects each other by anchor portion 86 or engages, thereby has reduced the distortion or the bending of the float electrode 82,83 that caused by variations in temperature during work and the inoperative.Described variable capacitor X8 can highly precisely work as variable capacitor X6.In addition, according to variable capacitor X8, can change the interstitial volume between the float electrode 82,83 significantly, and be easy to minimum electrostatic capacitance is set a smaller value, this is because this capacitor does not comprise through the fixing structure of the interelectrode distance of anchor portion 86.Therefore, as variable capacitor X6, variable capacitor X8 can provide big electrostatic capacitance change amount or rate of change.

Figure 82 and Figure 83 illustrate the manufacture method of variable capacitor X8 with a series of sectional views that correspond respectively to cross section shown in Figure 81.This method utilizes so-called MEMS technology to make variable capacitor X8.

In the manufacturing of variable capacitor X8, at first shown in Figure 82 (a), with the groove 81a in the expendable material 87 filling substrates 81.Particularly, carry out and fill expendable material 87 with reference to the described identical step of Figure 21 (b).

Then, shown in Figure 82 (b), on the substrate 81, promptly on expendable material 87, form float electrode 82.Float electrode 82 has opening 82a.Can utilize and form float electrode 82 with reference to the described identical process of fixed electrode 42 that is used to form of Figure 56 (a).

Then, shown in Figure 82 (c), form expendable film 88.Expendable film 88 has the opening 88a that is communicated with opening 82a.Can utilize and form expendable film 88 with reference to the described identical process of expendable film 47 that is used to form of Figure 56 (a).By controlling the thickness of the expendable film 88 that forms in this step, can control the initial condition distance L 8 between the float electrode 82,83 among the variable capacitor X8 of gained.

Then, shown in Figure 83 (a), formation has the opening 84a dielectric film 84 of (it is communicated with opening 88a).For example can form dielectric film 84 by following steps: at first form the film of predetermined dielectric material on the precalculated position by sputtering method, the mask through having predetermined resist pattern comes this film of etching then.

Then, shown in Figure 83 (b), formation has the opening 83a float electrode 83 of (it is communicated with opening 84a).For example can form float electrode 83 by following steps: at first form the aluminium film by sputter on dielectric film 84, expendable film 88 etc., the mask through having predetermined resist pattern comes etching aluminium film then.

Then, shown in Figure 83 (c), form stopper 85.For example,, fill the through hole that provides by opening 82a, 83a, 84a and 88a with dielectric material thus, can form stopper 85 by sputtering method.

, utilize predetermined resist remover carry out wet etching, to remove expendable film 88 and expendable material 87 thereafter.After the above-mentioned steps, can successfully produce variable capacitor X8.

Figure 84 is the sectional view of the change example of variable capacitor X8.This figure is corresponding to Figure 81 that the cross section of variable capacitor X8 among Figure 80 is shown.In variable capacitor X8, dielectric film 84 is formed on float electrode 83 top sides to float electrode 82; Substitute this configuration, dielectric film 84 can be formed on float electrode 82 top sides to float electrode 83, shown in Figure 84.Utilize and the identical method of above-mentioned manufacturing variable capacitor X8, and for example following the variation, can produce this change example.Particularly, with the step that forms float electrode 82, and the step that forms dielectric film 84 and expendable film 88 thereafter successively, replace the step that forms float electrode 82 and reach the step that forms expendable film 88 and dielectric film 84 thereafter successively.

Shown in Figure 85, can have the 85a of lid according to the stopper 85 of variable capacitor X8 (comprising above-mentioned change example).Shown lid 85a helps to guarantee the engagement relationship between float electrode 83 and the stopper 85.

Can be similar to the float electrode 22,23 of one of change example according to Figure 25, Figure 27, Figure 29, Figure 30, Figure 32, Figure 34, Figure 36 and variable capacitor X2 shown in Figure 38 according to the float electrode 82,83 of variable capacitor X8 (comprising above-mentioned change example), promptly can have the original shape that comprises sweep.Perhaps, can be similar to the float electrode 22,23 of one of change example according to Figure 26, Figure 28, Figure 31, Figure 33, Figure 35, Figure 37 and variable capacitor X2 shown in Figure 39 according to the float electrode 82,83 of variable capacitor X8 (comprising above-mentioned change example), promptly can have an original shape, it comprises sweep and has the part that contacts with fixed electrode through dielectric film.Moreover, can be similar to the float electrode 22,23 to one of change example of variable capacitor X2 shown in Figure 44 according to the float electrode 82,83 of variable capacitor X8 (comprising above-mentioned change example) according to Figure 40, promptly can interconnect by anchor portion 86 respectively, and have and the similar original shape of the float electrode 22,23 of Figure 40 to the change example shown in Figure 44 two positions.

Claims (22)

1, a kind of variable capacitor comprises:

Fixed electrode;

The float electrode film is in the face of this fixed electrode; And

Anchor portion is used for providing part to be connected between this fixed electrode and this float electrode film.

2, variable capacitor as claimed in claim 1, wherein this anchor portion penetrate this fixed electrode and this float electrode film at least one of them.

3, variable capacitor as claimed in claim 1 wherein also comprises the dielectric film that is arranged between this fixed electrode and this float electrode film, and this dielectric film keeps contacting with one of this float electrode film with this fixed electrode.

4, variable capacitor as claimed in claim 3, wherein the part of this dielectric film constitutes at least a portion of this anchor portion.

5, variable capacitor as claimed in claim 3, wherein the part of this float electrode film can be forced on this fixed electrode through this dielectric film.

6, variable capacitor as claimed in claim 3, wherein the part of this float electrode film is forced on this fixed electrode through this dielectric film.

7, variable capacitor as claimed in claim 1, wherein the part of this float electrode film is towards this fixed electrode bending.

8, variable capacitor as claimed in claim 1, wherein the part of this float electrode film is away from this fixed electrode bending.

9, a kind of variable capacitor comprises:

The first float electrode film respect to one another and the second float electrode film; And

Anchor portion is used for providing part to be connected between this first float electrode film and this second float electrode film.

10, variable capacitor as claimed in claim 9, wherein this anchor portion penetrate this first float electrode film and this second float electrode film at least one of them.

11, variable capacitor as claimed in claim 9 wherein also comprises the dielectric film that is arranged between this first float electrode film and this second float electrode film, and this dielectric film keeps contacting with one of this second float electrode film with this first float electrode film.

12, variable capacitor as claimed in claim 11, wherein the part of this dielectric film constitutes at least a portion of this anchor portion.

13, variable capacitor as claimed in claim 11, wherein this first float electrode film and this second float electrode film can be pressed towards each other through this dielectric film.

14, variable capacitor as claimed in claim 11, wherein this first float electrode film and this second float electrode film can partly be pressed to each other through this dielectric film.

15, variable capacitor as claimed in claim 9, wherein the part of this first float electrode film is towards this second float electrode film bending.

16, variable capacitor as claimed in claim 9, wherein the part of this first float electrode film is away from this second float electrode film bending.

17, variable capacitor as claimed in claim 9, wherein the part of this second float electrode film is towards this first float electrode film bending.

18, variable capacitor as claimed in claim 9, wherein the part of this second float electrode film is away from this first float electrode film bending.

19, a kind of manufacture method of variable capacitor, the method comprising the steps of:

On substrate, form first electrode;

On this first electrode, form anchor portion;

Form the expendable film that covers this first electrode and partly expose this anchor portion;

On this expendable film, form second electrode that is engaged to this anchor portion; And

Remove this expendable film.

20, a kind of manufacture method of variable capacitor, this method may further comprise the steps:

Form first electrode on substrate, this first electrode is formed with opening;

Form anchor portion, this anchor portion comprises the part in this opening of packing into and protrudes from the part of this first electrode;

Form the expendable film that covers this first electrode and partly expose this anchor portion;

On this expendable film, form second electrode that is engaged to this anchor portion; And

Remove this expendable film.

21, a kind of manufacture method of variable capacitor, this method may further comprise the steps:

On substrate, form first electrode;

Form the expendable film that covers this first electrode, this expendable film is formed with first opening that is used for partly exposing this first electrode;

Form second electrode on this expendable film, this second electrode is formed with second opening with this first open communication;

By fill this first opening and this second opening at least with material, on this first electrode, form the anchor portion that penetrates this expendable film and this second electrode; And

Remove this expendable film.

22, a kind of manufacture method of variable capacitor, this method may further comprise the steps:

Form first electrode on substrate, this first electrode is formed with first opening;

Form the expendable film that covers this first electrode, this expendable film is formed with second opening with this first open communication;

Form second electrode on this expendable film, this second electrode is formed with the 3rd opening with this second open communication;

By filling this first opening, this second opening and the 3rd opening at least, form the anchor portion that penetrates this first electrode, this expendable film and this second electrode with material; And

Remove this expendable film.

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