CN103390611B

CN103390611B - Single-ended inductor

Info

Publication number: CN103390611B
Application number: CN201210139652.4A
Authority: CN
Inventors: 黄景丰
Original assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2012-05-08
Filing date: 2012-05-08
Publication date: 2016-11-09
Anticipated expiration: 2032-05-08
Also published as: CN103390611A

Abstract

The invention discloses a kind of single-ended inductor, the wire coil of single-ended inductor is a snail cincture structure, and from the inner ring of wire coil to outer ring, the metal width of wire coil gradually broadens.Under high frequency, the skin depth of each position of close inner ring is less than the skin depth of outer ring, therefore after the metal width of inner ring reduces, the resistance near the position of inner ring can't increase, and will not reduce the electric current of wire coil；Meanwhile, after the metal width near inner ring reduces, the effective average departure defection between each adjacent metal wire sections of wire coil reduces, and just can increase the mutual inductance value between each adjacent metal wire sections of wire coil such that it is able to improve the inductance value of single-ended inductor.

Description

Single-ended inductor

Technical field

The present invention relates to a kind of semiconductor integrated circuit, particularly relate to a kind of single-ended inductor.

Background technology

In semiconductor integrated circuit, in radio-frequency devices, be often required to use inductance, by inductance and its Its semiconductor devices is integrated in same Semiconductor substrate together.In prior art, in radio-frequency devices Inductance typically uses planar spiral inductor, and the wire coil of inductance is a snail cincture structure, whole The wire coil of individual inductance is made in same metal level.Single-ended inductor is a kind of half-integer circle or integer The planar spiral inductor of circle, as it is shown in figure 1, be the wire coil schematic diagram of existing single-ended inductor；Existing The wire coil having single-ended inductor is a snail cincture structure, from the inner ring of described wire coil 11 arrive outer ring 12, and the metal width of described wire coil is all identical.

The metal width of the wire coil of existing single-ended inductor is the same from inside to outside, in high frequency, Due to the common effect of Kelvin effect and approach effect, electric current can in the redistribution in metallic conductor and Tend to the surface being distributed in metallic conductor, such that the resistance of metallic conductor becomes big.Such as Fig. 2 A Shown in, it is the Kelvin effect schematic diagram of the inner ring of the wire coil of existing single-ended inductor, inner ring 11 No current at the 11a of metallic conductor center, in CURRENT DISTRIBUTION at the 11b of metallic conductor surface；Such as Fig. 2 B Shown in, it is the Kelvin effect schematic diagram of the outer ring of the wire coil of existing single-ended inductor, outer ring 12 No current at the 12a of metallic conductor center, in CURRENT DISTRIBUTION at the 12b of metallic conductor surface.Comparison diagram 2A and Fig. 2 B understands, the skin depth of inner ring 11 is less than the skin depth of outer ring 12, inner ring 11 Electric current closer to the surface location of conductor at, so the resistance ratio outer ring 12 of inner ring 11 is big, electricity Stream major part only flows in skin depth, electric current can be made to reduce and finally also can reduce inductance value so that Inductance energy is lost.

As it is shown on figure 3, be the mutual inductance schematic diagram of the wire coil of existing single-ended inductor.By gold in Fig. 3 Belonging to coil and divide into 1-8 section, as shown by arrows, L1 is between metal segments 4 and 2 to the sense of current Distance, L2 is the distance between metal segments 5 and 7, d be between adjacent metal segments 1 and 5 away from From wherein the value of d is minimum.So mutual inductance between each metal segments of existing single-ended inductor mainly with Adjacent metal section such as 1 and 5,2 and 6, based on 3 and 7,4 and 8.When wire coil produces skin effect When answering and make electric current reduce, the mutual inductance between each adjacent metal segments can reduce, so that inductance value fall Low.

In prior art, in order to reduce the loss of inductance energy, a kind of method is to strengthen the width of metal And thickness, increase the cross-sectional area that electric current flows through, make resistance reduce.But consequently, it is possible to can increase again Add the overlapping capacitive reactance between metal so that resonant frequency declines, be thus degrading the quality of inductance because of Element (Q value).

Content of the invention

The technical problem to be solved is to provide a kind of single-ended inductor, improve the quality of device because of Element.

For solving above-mentioned technical problem, the wire coil of the single-ended inductor that the present invention provides is a plane spiral shell Rotation is around structure, from the inner ring of described wire coil to outer ring, the metal width of described wire coil by Gradual change width.

Further improving, the metal width in position for the described wire coil is set greater than being equal to Described wire coil is in the skin depth of this corresponding position.

Further improving, the spacing between the adjacent circling ring of described wire coil is identical.

Further improving, the spacing between the adjacent circling ring of described wire coil is different.

Further improve, the circling ring of described wire coil be shaped as square, rectangle, eight Dihedral, circular.

The present invention utilizes the skin depth of the inner ring of the wire coil of single-ended inductor to be less than becoming of outer ring The metal width of wire coil is gradually broadened from inner ring to outer ring by the feature of the skin degree of depth, near inner ring Metal width be less than the metal width near outer ring, but owing to the skin depth of inner ring is less than The skin depth of outer ring, therefore after the metal width of inner ring reduces, near the position of inner ring Resistance can't increase, so relative to prior art, the present invention will not reduce the electric current of wire coil； Meanwhile, after the metal width near inner ring reduces, between each adjacent metal wire sections of wire coil Effective average departure defection reduces, and thus can increase between each adjacent metal wire sections of wire coil Mutual inductance value such that it is able to improve single-ended inductor inductance value.

Brief description

The present invention is further detailed explanation with detailed description of the invention below in conjunction with the accompanying drawings:

Fig. 1 is the wire coil schematic diagram of existing single-ended inductor；

Fig. 2 A is the Kelvin effect schematic diagram of the inner ring of the wire coil of existing single-ended inductor；

Fig. 2 B is the Kelvin effect schematic diagram of the outer ring of the wire coil of existing single-ended inductor；

Fig. 3 is the mutual inductance schematic diagram of the wire coil of existing single-ended inductor；

Fig. 4 is the wire coil schematic diagram of embodiment of the present invention single-ended inductor；

Fig. 5 is the simulation curve of the quality factor of embodiment of the present invention single-ended inductor.

Detailed description of the invention

As shown in Figure 4, it is the wire coil schematic diagram of embodiment of the present invention single-ended inductor.The present invention is real The wire coil executing example single-ended inductor is a snail cincture structure, from the inner ring of described wire coil 101 arrive outer ring 102, and the metal width of described wire coil gradually broadens.And described wire coil exists The metal width of position is set greater than equal to described wire coil becoming in this corresponding position The skin degree of depth.The method that can use emulation of the skin depth of position obtains, and emulates such as EMX etc. Software.From shown in Fig. 2 A and Fig. 2 B, the skin depth of inner ring 101 becomes less than outer ring 102 The skin degree of depth, therefore the ratio outer ring 102 that the width of inner ring 101 can be arranged is smaller.But inner ring After the width of 101 reduces, owing to the value of this width is still greater than the skin depth of inner ring 101, therefore The resistance of inner ring 101 does not increase relative to the situation reducing front i.e. prior art.In like manner, described gold The resistance of other circling rings belonging to coil does not increases yet.

Spacing between the adjacent circling ring of described wire coil is identical, between changing in other embodiments Away from difference also can be set to.It is filled with dielectric layer between the adjacent circling ring of described wire coil.Institute State wire coil circling ring be shaped as square, in other embodiments, described wire coil The shape of circling ring also can be rectangle, octagonal, circular.

From fig. 4, it can be seen that the embodiment of the present invention is compared to the prior art, when described wire coil The spacing of the adjacent spacing between circling ring and prior art is set to mutually simultaneously as the present invention is real The width of the metal wire sections executing the close inner ring of example can reduce, so each adjacent metal of wire coil Effective average departure defection between line segment reduces, and this effective average distance is that distance values adds that two is adjacent The half of width sum of metal wire sections, so effective average departure defection reduces.Effective average departure After reducing, the mutual inductance value between each adjacent metal wire sections of wire coil can be increased such that it is able to Improve the inductance value of single-ended inductor.

As it is shown in figure 5, be the simulation curve of the quality factor of embodiment of the present invention single-ended inductor.Curve The simulation curve of the quality factor that 103 is embodiment of the present invention single-ended inductor, curve 104 is existing list The simulation curve of the quality factor of end inductance. The structural parameters of existing single-ended inductor are: external diameter is 280 microns, and metal width is 8 microns, metal Spacing 2 microns, the number of turns is 3.Wherein external diameter is that the metal wire sections center, side of outer ring is to opposite side The distance at metal wire sections center, as shown in the L1 of Fig. 3.

The structural parameters of embodiment of the present invention single-ended inductor are: external diameter is 280 microns, the metal of outer ring Width is 8 microns, and the metal width of inner ring is 6 microns, and a middle circle metal width is 7 microns, Metal spacing 2 microns, the number of turns is 3.

In terms of simulation result, owing to Kelvin effect is inconspicuous under low frequency, the quality of above two device because of Element is substantially similar, but under high frequency, (more than 2GHz) compares due to Kelvin effect and kindred effect Seriously, the quality factor of embodiment of the present invention device is improved clearly, and quality factor carries from 14.9 High to 16.1.

Above by specific embodiment, the present invention has been described in detail, but these not constitute right The restriction of the present invention.Without departing from the principles of the present invention, those skilled in the art also can do Going out many deformation and improving, these also should be regarded as protection scope of the present invention.

Claims

1. a single-ended inductor, it is characterised in that: the wire coil of single-ended inductor is a snail Around structure, from the inner ring of described wire coil to outer ring, the metal width of described wire coil is gradually Broaden；

The metal width in position for the described wire coil is set greater than equal to described wire coil In the skin depth of this corresponding position, utilize the skin depth of the inner ring of the wire coil of single-ended inductor It is less than the feature of the skin depth of outer ring, do not increase at the resistance making the position near inner ring Under the conditions of make near inner ring position metal width reduce.

2. single-ended inductor as claimed in claim 1, it is characterised in that: the phase of described wire coil The adjacent spacing between circling ring is identical.

3. single-ended inductor as claimed in claim 1, it is characterised in that: the phase of described wire coil The adjacent spacing between circling ring is different.

4. single-ended inductor as claimed in claim 1, it is characterised in that: the ring of described wire coil Pitch of the laps be shaped as square, rectangle, octagonal, circular.