JP6575312B2 - LC composite device and processor - Google Patents

Description

  The present invention relates to an LC composite device including a thin film inductor and a thin film capacitor, and further to a processor including the LC composite device.

  An integrated passive device (IPD) in which a thin film inductor and a thin film capacitor are integrally formed on a semiconductor substrate by a thin film process is particularly useful as a composite passive component for mobile terminals because it is small and thin (for example, patents) References 1, 2).

JP-A-6-53406 JP 2001-44778 A

  However, as shown in Patent Document 1, when a thin film capacitor and a thin film inductor are arranged side by side on a semiconductor substrate, a space required to form these thin film elements becomes large. Further, as shown in Patent Document 2, in the structure in which the thin film inductor is disposed on the upper side of the thin film capacitor, the distance from the input / output terminal to the thin film capacitor is increased, and the parasitic inductor component during this time affects the high frequency characteristics. Will be affected. Furthermore, in any structure, since the magnetic field of the thin film inductor is hindered by the capacitor electrode and the semiconductor substrate, it is difficult to configure an inductor having a high Q value.

  An object of the present invention is to solve the above-described problems and provide an LC composite device including a capacitor with reduced parasitic inductance, an inductor having a high Q value, and a processor including the same.

(1) The LC composite device of the present invention is
A semiconductor substrate on which a redistribution layer is formed, and a thin film inductor and a thin film capacitor formed on the semiconductor substrate or the redistribution layer,
The thin film capacitor includes a first capacitor electrode and a second capacitor electrode facing each other,
The thin film inductor is formed outside a formation range of the thin film capacitor in a plan view, and has a meander shape when viewed from a side surface direction of the redistribution layer.

  With the above configuration, the thin film inductor has a meander shape as viewed from the side surface in the rewiring layer, so that the magnetic field of the thin film inductor is not easily disturbed by the capacitor electrode or the semiconductor substrate, and an inductor having a high Q value is configured. In addition, since the distance from the input / output terminal formed on the outer surface of the redistribution layer to the thin film capacitor is shortened, a thin film capacitor having a small parasitic inductance can be obtained.

(2) It is preferable that the thin film inductor includes a plurality of first inductor conductors, a plurality of second inductor conductors formed in an upper layer than the first inductor conductors, and an interlayer connection conductor that sequentially connects them. As a result, a thin-film inductor having a meander shape in the stacking direction is formed while having a simple pattern composed of three types of conductors.

(3) In the above (2), preferably, the first inductor conductor and the first capacitor electrode are provided in the same layer, and the second inductor conductor and the second capacitor electrode are provided in the same layer. Thereby, a thin film inductor and a thin film capacitor can be configured with a small number of layers, the manufacturing process is simplified, and the cost can be reduced.

(4) In the above (2) or (3), it is preferable that the total extension of the interlayer connection conductor is 1/3 or more of the total extension of the thin film inductor. Thus, a thin film inductor having a high Q value is obtained when the proportion of the interlayer connection conductor having a small resistance value per line length is larger than that of the first and second inductor conductors.

(5) In any one of the above (1) to (4), a first terminal, a second terminal, and a third terminal are formed on the outer surface of the redistribution layer, respectively, and the first end of the thin film inductor is the first end A second end of the thin film inductor is connected to the second terminal, the first capacitor electrode is connected to a second end of the thin film inductor, and the third terminal is the second terminal in plan view. Preferably, the second capacitor electrode is disposed at a position overlapping the capacitor electrode, and the second capacitor electrode is connected to the third terminal. As a result, the distance from the third terminal to the thin film capacitor is minimized, and a thin film capacitor with a smaller parasitic inductance is obtained.

(6) In any one of (1) to (5), the thin film inductor is a loop that circulates around the first capacitor electrode and the second capacitor electrode when viewed from the normal direction of the redistribution layer. It is preferable to make a shape. Thereby, the path length per occupied area of the thin film inductor can be increased, and a small LC composite device having a thin film inductor having a predetermined inductance can be obtained.

(7) A processor of the present invention includes a processor integrated circuit including a switching circuit of a switching power supply circuit, and an LC composite device connected to the switching circuit,
The LC composite device is:
A semiconductor substrate on which a redistribution layer is formed;
A thin film inductor and a thin film capacitor formed on the semiconductor substrate or the rewiring layer;
An LC composite device comprising:
The thin film capacitor includes a first capacitor electrode and a second capacitor electrode facing each other,
The thin film inductor has a meander shape when viewed from a side surface direction of the rewiring layer.

  With the above configuration, by connecting a small LC composite device to a processor integrated circuit, it can be used as a miniaturized processor including a switching power supply circuit.

  According to the present invention, an LC composite device including a thin film inductor having a high Q value is configured. Further, a miniaturized processor including a switching power supply circuit is configured.

FIG. 1 is a perspective view of the LC composite device according to the first embodiment. 2A is a cross-sectional view taken along a plane passing through the first terminal 31 and the second terminal 32 in FIG. 1, and FIG. 2B is a cross-sectional view taken along a plane passing through the third terminal 33 in FIG. It is. FIG. 3 is a plan view of the LC composite device 102 according to the second embodiment. 4A is a diagram showing the positional relationship of a plurality of interlayer connection conductors in the thin film inductor TFL shown in FIG. 3, and FIG. 4B is a diagram showing an example of the direction of current flowing in each interlayer connection conductor. It is. 5 (A) and 5 (B) are diagrams showing comparative examples for FIGS. 4 (A) and 4 (B). FIG. 6 is a partial plan view of the LC composite device 103 according to the third embodiment. FIG. 7 is a circuit diagram of the LC composite device of this embodiment. FIG. 8 is a conceptual diagram showing the connection structure of the smoothing circuit to the processor. FIG. 9 is a diagram illustrating a mounting structure of the LC composite device 101 and a mounting structure of the processor chip 201. 10A, 10B, and 10C are circuit diagrams illustrating a plurality of application examples of the LC composite device to the power supply circuit.

<< First Embodiment >>
FIG. 1 is a perspective view of the LC composite device according to the first embodiment. However, the rewiring layer 3 is shown through the conductor portion and the electrode portion.

The LC composite device 101 includes a semiconductor substrate 1 such as Si having an insulator layer 1S such as SiO _{2 on} the surface, and a rewiring layer 3 formed on the surface of the insulator layer 1S. The LC composite device 101 includes a semiconductor substrate 1 and a thin film inductor TFL and a thin film capacitor TFC formed on the insulator layer 1S or the rewiring layer 3.

  The thin film capacitor TFC includes a first capacitor electrode 11 and a second capacitor electrode 12 facing each other.

  The thin film inductor TFL has a meander shape as viewed from the side surface direction of the rewiring layer 3.

  Specifically, the thin film inductor TFL includes a plurality of first inductor conductors 21, a plurality of second inductor conductors 22 formed above the first inductor conductor 21, and an interlayer connection conductor 23 that sequentially connects these. The As a result, a thin-film inductor having a meander shape in the stacking direction is formed while having a simple pattern composed of three types of conductors (first inductor conductor 21, second inductor conductor 22, and interlayer connection conductor 23).

  A first terminal 31, a second terminal 32, and a third terminal 33 are formed on the outer surface (the upper surface in FIG. 1) of the rewiring layer 3, respectively. The first end of the thin film inductor TFL is connected to the first terminal 31, and the second end of the thin film inductor TFL is connected to the second terminal 32. The first capacitor electrode 11 is connected to the second end (second terminal 32) of the thin film inductor TFL.

  2A is a cross-sectional view taken along a plane passing through the first terminal 31 and the second terminal 32 in FIG. 1, and FIG. 2B is a cross-sectional view taken along a plane passing through the third terminal 33 in FIG. It is.

  The first inductor conductor 21 and the first capacitor electrode 11 are provided in the same layer, and the second inductor conductor 22 and the second capacitor electrode 12 are provided in the same layer. Thereby, the thin film inductor TFL and the thin film capacitor TFC can be configured with a small number of layers, the manufacturing process is simplified, and the cost can be reduced.

  In the thin film inductor TFL, the total extension of the interlayer connection conductor 23 is 1/3 or more of the total extension of the thin film inductor TFL (the total extension of the first inductor conductor 21, the second inductor conductor 22, and the interlayer connection conductor 23). Is preferred. Furthermore, it is preferable that it is 1/2 or more. Since the interlayer connection conductor 23 has a smaller resistance value per line length than the first inductor conductor 21 and the second inductor conductor 22, if the proportion of the interlayer connection conductor 23 is large, the thin film inductor TFL A thin film inductor having a small DC resistance DCR and a high Q value can be obtained.

  As shown in FIG. 2B, the second capacitor electrode 12 is connected to the third terminal 33 via the interlayer connection conductor 13. The distance between the second capacitor electrode 12 and the third terminal 33 can be made extremely short. That is, since the distance from the third terminal 33 to the thin film capacitor TFC can be shortened, a thin film capacitor TFC with a small parasitic inductance can be obtained.

  The thin film inductor TFL has a loop shape that goes around the first capacitor electrode 11 and the second capacitor electrode 12 when viewed from the normal direction of the redistribution layer 3 (that is, in plan view). In the present embodiment, a loop for one turn is formed in plan view. Thereby, the path length per occupied area of the thin film inductor TFL can be increased, and the small LC composite device 101 having the thin film inductor TFL having a predetermined inductance can be obtained. Particularly, since the area around the thin film capacitor TFC is a dead space for the thin film capacitor TFC, the occupied area on the substrate is reduced as compared with the case where the thin film inductor TFL and the thin film capacitor TFC are juxtaposed.

<< Second Embodiment >>
In the second embodiment, an LC composite device including a thin film inductor having a loop shape of a plurality of turns in plan view will be described.

  FIG. 3 is a plan view of the LC composite device 102 according to the second embodiment. The LC composite device 102 includes a semiconductor substrate 1 having an insulator layer on the surface and a rewiring layer formed on the surface of the insulator layer. The LC composite device 102 includes a thin film inductor TFL and a thin film capacitor TFC formed in the redistribution layer 3.

  The thin film capacitor TFC includes a first capacitor electrode 11 and a second capacitor electrode 12 facing each other.

  The thin film inductor TFL has a meander shape when viewed from the side surface direction of the redistribution layer 3, and has a loop shape with a plurality of turns in plan view.

  Specifically, the thin film inductor TFL includes a plurality of first inductor conductors 21, a plurality of second inductor conductors 22 formed above the first inductor conductor 21, and an interlayer connection conductor 23 that sequentially connects these. The Unlike the LC composite device 101 shown in the first embodiment, the first inductor conductor 21, the second inductor conductor 22, and the interlayer connection conductor 23 are arranged in a rectangular spiral shape having a plurality of turns in plan view.

  A first terminal 31, a second terminal 32, and a third terminal 33 are formed on the outer surface of the redistribution layer. The first end of the thin film inductor TFL is connected to the first terminal 31, and the second end of the thin film inductor TFL is connected to the second terminal 32. The first capacitor electrode 11 is connected to the second end (second terminal 32) of the thin film inductor TFL.

  As described above, when the thin film inductor TFL having a plurality of turns is configured in plan view, the plurality of interlayer connection conductors 23 in a certain turn are respectively connected to the plurality of interlayer connection conductors 23 in the turn adjacent to the outer periphery or the inner periphery. Adjacent to each other. The self-inductance changes depending on the positional relationship between the interlayer connection conductors having different laps.

  4A is a diagram showing the positional relationship of a plurality of interlayer connection conductors in the thin film inductor TFL shown in FIG. 3, and FIG. 4B is a diagram showing an example of the direction of current flowing in each interlayer connection conductor. It is. FIGS. 5A and 5B are diagrams showing comparative examples with respect to FIGS. 4A and 4B. In this comparative example, the first inductor conductor 21 and the second inductor conductor 22 are adjacent to each other in plan view.

  As is clear from FIG. 4B, the current direction is the same for each of the pair of adjacent interlayer connection conductors 23a-23e, 23b-23f, 23c-23g, and 23d-23h. Becomes larger. On the other hand, in the comparative example, as is clear from FIG. 5B, the direction of current for each of the pair of adjacent interlayer connection conductors, 23a-23f, 23b-23g, 23c-23h, and 23d-23i, Since it is in the reverse direction, the self-inductance is small.

  4A, 4B, and 5A, 5B, the interlayer connection conductors 23a-23d and the interlayer connection conductors 23e-23h, or the interlayer connection conductors 23a-23d and the interlayer connection conductors 23f-23i, However, although an example of juxtaposition with the same pitch and the same phase was shown. The pitch may be different or the phase of the pitch may be different. Then, the self-inductance may be determined by the phase of this pitch.

  As described above, the self-inductance can be appropriately determined according to the positional relationship between the interlayer connection conductors having different laps.

<< Third Embodiment >>
In 3rd Embodiment, the example which provided the thin film inductor and the thin film capacitor with conductor patterns other than those is shown.

  FIG. 6 is a partial plan view of the LC composite device 103 according to the third embodiment. The LC composite device 103 includes a semiconductor substrate 1 provided with a predetermined integrated circuit, and a rewiring layer formed on the surface of the semiconductor substrate 1. The LC composite device 103 includes a thin film inductor and a thin film capacitor formed on the semiconductor substrate 1 or the redistribution layer 3.

  The thin film capacitor includes a first capacitor electrode 11 and a second capacitor electrode 12 facing each other.

  The thin film inductor includes a plurality of first inductor conductors 21, a plurality of second inductor conductors 22 formed above the first inductor conductor 21, and an interlayer connection conductor 23 that sequentially connects them. Unlike the LC composite device 102 shown in the second embodiment, the first inductor conductor 21, the second inductor conductor 22, and the interlayer connection conductor 23 are arranged in a meander shape in plan view. In the rewiring layer, conductor patterns 14 and 15 other than the thin film capacitor and the thin film inductor are formed. The thin film inductor is disposed so as to avoid the conductor patterns 14 and 15 and the thin film capacitor (in the conductor patterns 14 and 15 and the remaining portion of the thin film capacitor).

  A first terminal 31, a second terminal 32, and a third terminal 33 are formed on the outer surface of the redistribution layer. The first end of the thin film inductor is connected to the first terminal 31, and the second end of the thin film inductor is connected to the second terminal 32. The first capacitor electrode 11 is connected to the second end (second terminal 32) of the thin film inductor.

  FIG. 7 is a circuit diagram of the LC composite device of this embodiment. In the present embodiment, since the first capacitor electrode 11 is connected in the middle of the thin film inductor, an LCL T-type circuit is configured as shown in FIG.

  According to the present embodiment, the first inductor conductor 21, the second inductor conductor 22, and the interlayer connection conductor 23 formed in the redistribution layer of the semiconductor substrate also function as a heat conductor. That is, the thin film inductor improves the heat dissipation of the semiconductor substrate.

  In the embodiment described above, an example in which the thin film inductor TFL and the thin film capacitor TFC are configured in the redistribution layer 3 formed on the insulator layer 1S on the surface of the semiconductor substrate 1 has been described. One or both of the one capacitor electrodes 11 may be formed on the semiconductor substrate. Further, one or both of the first inductor conductor 21 and the first capacitor electrode 11 may be formed of a diffusion layer of a semiconductor substrate.

<< Fourth Embodiment >>
The fourth embodiment shows an example of a processor according to the present invention.

  FIG. 8 is a conceptual diagram showing the connection structure of the smoothing circuit to the processor. The processor chip 201 is, for example, an application processor chip, and includes a switching circuit 201D of a switching power supply circuit. Switching circuit 201D includes a switching element of a DC / DC converter and a switching control circuit thereof. The LC composite device 101 is provided outside the processor chip 201 and is connected to the switching circuit 201D via a wiring pattern.

  The configuration of the LC composite device 101 is as shown in the first embodiment. Terminals P1, P2, and P3 in FIG. 8 correspond to the first terminal 31, the second terminal 32, and the third terminal 33, respectively.

  FIG. 9 is a diagram illustrating a mounting structure of the LC composite device 101 and a mounting structure of the processor chip 201. The processor chip 201 is an integrated circuit in a bare chip state, and solder balls SB are attached to a plurality of pads for external connection. The LC composite device 101 is attached to a pad connected to the power supply circuit.

  The processor chip 201 to which the solder balls and the LC composite device 101 are attached is mounted on the printed wiring board 301.

  The processor chip 201 with the LC composite device 101 shown in FIG. 9 is obtained, for example, by the following method.

(1) In a wafer state before being separated into processor chips, the solder balls SB are mounted on a position other than the mounting position of the LC composite device 101 on the wafer.

(2) A solder ball is mounted on the first terminal 31, the second terminal 32, and the third terminal 33 of the LC composite device 101, and a flux is applied to the solder ball, or a flux is applied to the wafer side. Is mounted on a wafer.

(3) The LC composite device 101 is mounted on the wafer by a reflow process.

(4) The wafer is diced by a dicing process to constitute a processor chip with the LC composite device 101.

  By mounting the processor chip 201 with the LC composite device 101 on the printed wiring board 301, the LC composite device 101 is disposed in the gap between the processor chip 201 and the printed wiring board 301.

  The LC composite device 101 may be mounted on the printed wiring board 301 side, and the LC composite device 101 may be connected to the power supply circuit of the processor chip 201 via a wiring pattern formed on the printed wiring board 301.

<< Fifth Embodiment >>
In the fifth embodiment, a plurality of application examples of the LC composite device to the power supply circuit will be described.

  FIG. 10A is a basic circuit diagram of the step-down chopper. The step-down chopper includes a switching element Q1, a diode D1, an inductor L1, and a capacitor C1, and steps down the voltage of the input power supply E1 to supply a predetermined power supply voltage to the load RL.

  When applied to this type of power supply circuit, the inductor L1 and the capacitor C1 are constituted by the LC composite device 101.

  FIG. 10B is a basic circuit diagram of the boost chopper. The step-up chopper includes a switching element Q1, a diode D1, an inductor L1, and capacitors C1 and C2, and boosts the voltage of the input power supply E1 to supply a predetermined power supply voltage to the load RL.

  When applied to this type of power supply circuit, the LC composite device 101 includes the inductor L1 and the input-side capacitor C1.

  FIG. 10C is a basic circuit diagram of the buck-boost chopper. The step-up / step-down chopper includes a switching element Q1, a diode D1, an inductor L1, and a capacitor C1, and boosts or steps down the voltage of the input power supply E1 to supply a predetermined power supply voltage to the load RL.

  When applied to this type of power supply circuit, the inductor L1 and the capacitor C1 are constituted by the LC composite device 101.

  In the example shown above, the LC composite device is applied to the switching power supply circuit. However, the LC composite device of the present invention is applied to various signal processing circuits such as a filter and a phase shifter in addition to the power supply circuit. You can also.

  Finally, the description of the above embodiment is illustrative in all respects and not restrictive. Modifications and changes can be made as appropriate by those skilled in the art. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

C1, C2 ... Capacitor D1 ... Diode E1 ... Input power supply L1 ... Inductors P1, P2, P3 ... Terminal Q1 ... Switching element RL ... Load SB ... Solder ball TFC ... Thin film capacitor TFL ... Thin film inductor 1 ... Semiconductor substrate 1S ... Insulator layer 3 ... redistribution layer 11 ... first capacitor electrode 12 ... second capacitor electrode 13 ... interlayer connection conductors 14, 15 ... conductor pattern 21 ... first inductor conductor 22 ... second inductor conductor 23 ... interlayer connection conductors 23a-23i ... interlayer Connection conductor 31 ... first terminal 32 ... second terminal 33 ... third terminals 101, 102, 103 ... LC composite device 201 ... processor chip 201D ... switching circuit 301 ... printed wiring board

Claims (7)

A semiconductor substrate on which a redistribution layer is formed;
A thin film inductor and a thin film capacitor formed on the semiconductor substrate or the rewiring layer;
An LC composite device comprising:
The thin film capacitor includes a first capacitor electrode and a second capacitor electrode facing each other,
The thin film inductor is formed outside the formation range in the plan view of the thin film capacitor, to name a meander shape when viewed from the side of the redistribution layer,
A first terminal, a second terminal, and a third terminal are formed on the outer surface of the rewiring layer,
A first end of the thin film inductor is connected to the first terminal; a second end of the thin film inductor is connected to the second terminal;
The first capacitor electrode is connected to a second end of the thin film inductor;
The third terminal is disposed at a position overlapping the second capacitor electrode in plan view, and the second capacitor electrode is connected to the third terminal;
LC composite device. A semiconductor substrate on which a redistribution layer is formed;
A thin film inductor and a thin film capacitor formed on the semiconductor substrate or the rewiring layer;
An LC composite device comprising:
The thin film capacitor includes a first capacitor electrode and a second capacitor electrode facing each other,
The thin film inductor is formed outside the formation range in plan view of the thin film capacitor, and has a meander shape as viewed from the side surface direction of the redistribution layer,
The thin film inductor has a loop shape that circulates around the first capacitor electrode and the second capacitor electrode when viewed from the normal direction of the redistribution layer.
LC composite device. The thin film inductor, a plurality of first inductor conductor, and a plurality of second inductor conductor and interlayer connection conductors to which they are sequentially connected, which is formed in an upper layer than the first inductor conductor, to claim 1 or 2 The LC composite device described. The LC composite device according to claim 3 , wherein the first inductor conductor and the first capacitor electrode are provided in the same layer, and the second inductor conductor and the second capacitor electrode are provided in the same layer. The LC composite device according to claim 3 or 4 , wherein a total extension of the interlayer connection conductor is 1/3 or more of a total extension of the thin film inductor. A processor comprising a processor integrated circuit including a switching circuit of a switching power supply circuit and an LC composite device connected to the switching circuit;
The LC composite device is:
A semiconductor substrate on which a redistribution layer is formed;
A thin film inductor and a thin film capacitor formed on the semiconductor substrate or the rewiring layer;
An LC composite device comprising:
The thin film capacitor includes a first capacitor electrode and a second capacitor electrode facing each other,
The thin film inductor is formed outside the formation range in the plan view of the thin film capacitor, to name a meander shape when viewed from the side of the redistribution layer,
A first terminal, a second terminal, and a third terminal are formed on the outer surface of the rewiring layer,
A first end of the thin film inductor is connected to the first terminal; a second end of the thin film inductor is connected to the second terminal;
The first capacitor electrode is connected to a second end of the thin film inductor;
The third terminal is disposed at a position overlapping the second capacitor electrode in plan view, and the second capacitor electrode is connected to the third terminal;
Processor.   A processor comprising a processor integrated circuit including a switching circuit of a switching power supply circuit and an LC composite device connected to the switching circuit;
  The LC composite device is:
  A semiconductor substrate on which a redistribution layer is formed;
  A thin film inductor and a thin film capacitor formed on the semiconductor substrate or the rewiring layer;
An LC composite device comprising:
  The thin film capacitor includes a first capacitor electrode and a second capacitor electrode facing each other,
  The thin film inductor is formed outside the formation range in plan view of the thin film capacitor, and has a meander shape as viewed from the side surface direction of the redistribution layer,
  The thin film inductor has a loop shape that circulates around the first capacitor electrode and the second capacitor electrode when viewed from the normal direction of the redistribution layer.
  Processor.

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