JPH06252460A - Josephson device mounting circuit board - Google Patents

Abstract

PURPOSE:To provide a circuit board which is capable of feeding an electric power to a Josephson device through a polyphase pulsating current power supply system and being mounted with Josephson devices high in density. CONSTITUTION:A Josephson device mounting circuit board 2 is primarily composed of an insulating board 4 and an insulating layer 5 which includes an inner circuit 60 and is formed on the insulating board 4. An alternating current power supply circuit 9 which feeds two alternating currents different from each other in phase to Josephson devices 3 and a direct current power supply circuit 8 which feeds a direct bias current to the Josephson devices 3 to control timing between the output pluses of two alternating currents are provided inside the insulating board 4. The direct current power supply circuit 8 is composed of circuit patterns provided onto sheets 6a and 6b which constitute the insulating board 4, and an LC filter which restrains an alternating current and a direct bias current from interfering with each other is composed of a capacitance between the circuit patterns and an inductance of the circuit patterns.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board, and more particularly to a Josephson device mounting circuit board.

[0002]

2. Description of the Related Art A multilayer pulsating current power supply system is known as a power supply system for realizing a high speed operation of a Josephson device. This power supply system is a system in which power supply currents are supplied to each Josephson element in different phases. A Josephson element driving device for realizing such a multilayer pulsating current power supply system is mainly composed of a circuit board and a Josephson element mounted on the circuit board. Here, the circuit board includes an AC power supply circuit for supplying two kinds of AC currents having different phases to the Josephson element and a Josephson device for adjusting the timing between the output pulses of the two kinds of AC power. A DC power supply circuit for supplying a DC bias current to the device is incorporated. Each Josephson element mounted on the circuit board has a built-in primary coil connected to the AC power supply circuit and a secondary coil connected to the DC power supply circuit. Further, in the Josephson element, a low-pass filter for suppressing mutual interference between the alternating current and the direct current bias current is formed at the connecting portion between the secondary coil and the direct current power supply circuit. The low pass filter is generally an LC filter.

[0003]

In the above-mentioned conventional Josephson element driving device, each Josephson element has a built-in low-pass filter in order to realize a stable multi-layer pulsating current power supply system. However, it is difficult to mount the elements on the circuit board with high density. In particular, if the capacitance of the low-pass filter built into the Josephson device is increased in order to secure a sufficient function as a filter, the area occupied by the filter in the device becomes large, and high-density mounting of the device becomes more difficult. It will be difficult.

An object of the present invention is to realize a circuit board for mounting a Josephson element, which supplies electric power to the Josephson element by a multi-layer pulsating current power supply system and which enables high-density mounting of the Josephson element.

[0005]

A circuit board for mounting a Josephson device according to the present invention comprises an AC power supply circuit for supplying two kinds of alternating currents having different phases to the Josephson device.
A direct current power supply circuit for supplying a direct current bias current to the Josephson device to adjust the timing between the output pulses of the two types of alternating current; and an alternating current and a direct current bias current formed integrally with the direct current power supply circuit. And a low pass filter for suppressing mutual interference with each other, and an insulating substrate in which each circuit and the low pass filter are incorporated and a Josephson element is mounted.

[0006]

The circuit board for mounting the Josephson device of the present invention is
Two kinds of alternating current and direct current bias current having different phases are supplied from the alternating current power supply circuit and the direct current power supply circuit to the Josephson element mounted on the insulating substrate. Since a low-pass filter for suppressing mutual interference between AC current and DC bias current is formed integrally with the DC power supply circuit in the insulating substrate, the low-pass filter is built in on the Josephson device side. No need. As a result, a large number of small Josephson devices without a low-pass filter can be densely mounted on the circuit board of the present invention.

[0007]

1 and 2 show a Josephson element driving device 1 to which an embodiment of the present invention is applied. Note that FIG.
[Fig. 2] is a vertical sectional view of the Josephson element driving device 1, and Fig. 2 is a plan view. In the figure, the Josephson element driving device 1 is mainly composed of a circuit board 2 as an embodiment of the present invention and four Josephson elements 3 mounted on the circuit board 2. In addition, each Josephson element 3
Incorporates four power loads consisting of hundreds of logic gates.

The circuit board 2 includes an insulating substrate 4 made of, for example, mullite ceramics, and an insulating layer 5 made of polyimide resin formed on the insulating substrate 4. The insulating substrate 4 is an integrated sheet 6 obtained by laminating seven ceramic green sheets and firing them integrally.
a, 6b, 6c, 6d, 6e, 6f, 6g, and has a built-in internal circuit 7 including a DC power supply circuit 8 and an AC power supply circuit 9.

The DC power supply circuit 8 includes sheets 6b and 6c.
Of the circuit pattern formed on the two layers. 3 and 4, the formation pattern of the DC power supply circuit 8 formed on the sheets 6b and 6c is shown. In FIG. 3, on the sheet 6b, four sets of DC supply patterns 10 arranged substantially in the center thereof, four sets of DC introduction patterns 11 arranged at the left end of the figure, and arranged DC introduction patterns 11 are arranged. It is provided with a pair of alternating current introduction patterns 12 provided on both sides of the group and a ground pattern 13 formed on almost the entire surface except the above-mentioned patterns 10, 11, 12.

Each DC supply pattern 10 has a pair of land patterns 14, 14. Each land pattern 1
4 has through holes 15 penetrating the sheet 6a, that is, extending toward the front side in the drawing, at both ends of the portion facing the other land pattern 14. The through hole 15 is for supplying a DC bias current to the Josephson element 3 via an internal circuit 60, which will be described later, formed in the insulating layer 5. In addition, a large number of through holes 16 that penetrate the sheet 6b are formed in the center of each land pattern 14.

An AC supply pattern 17 is formed on both ends of the pair of land patterns 14, 14 while being insulated from the land pattern 14. Each AC supply pattern 1
7, a pair of through holes 18, 18 are formed toward the front side of the drawing, that is, so as to penetrate the sheet 6a. The through holes 18 and 18 are formed through the internal circuit 60 formed in the insulating layer 5 and the Josephson element 3
It is for supplying AC power to.

Each DC introduction pattern 11 and AC introduction pattern 12 has a large number of through holes 19. The through hole 19 extends in both directions within the seat 6a and the seat 6b. The ground pattern 13 is the sheet 6
It has a large number of blanks 20 arranged in the longitudinal direction at both widthwise end portions of a. The blank 20 is for canceling unnecessary capacitance formed between an internal circuit 60, which will be described later, formed in the insulating layer 5 and the ground pattern 13. In addition, the ground pattern 13
A slit 21 is formed in the vicinity of each DC supply pattern 10. This slit 21 is for equalizing the electric resistance to each Josephson element 3 in order to make the DC bias current supplied from each DC supply pattern 10 to the corresponding Josephson element 3 constant.

On the other hand, on the sheet 6c, two sets of direct current introducing patterns 25, which extend from the vicinity of the left end of the drawing toward the central portion,
25 and a pair of alternating current introduction patterns 26, 26 formed corresponding to the alternating current introduction patterns 12, 12 of the sheet 6b.
And a ground pattern 27 formed on almost the entire surface of the sheet 6b while being insulated from the patterns 25 and 26 described above.

Each DC introduction pattern 25 has a pair of pattern lines 28a and 28b. Each pattern line 2
Left end portions 29 of the sheets 8a and 28b in the figure face the direct current introducing pattern 11 of the sheet 6b with the sheet 6b interposed therebetween, and are connected to each other through the through holes 19. On the other hand, the other ends of both pattern lines 28a and 28b are bifurcated, and the tips thereof form land portions 30, respectively. Each land portion 30 faces the land pattern 14 provided on the sheet 6b with the sheet 6a interposed therebetween, and is connected to the corresponding land pattern 14 through the through hole 16.

An AC supply pattern 31 is formed in the vicinity of each land 30 so as to correspond to the AC supply pattern 17 of the sheet 6b. Each AC supply pattern 31
It has a pair of through holes 32, 32. The through holes 32, 32 extend in both directions in the sheet 6c and the sheet 6b and are connected to the AC supply pattern 17 of the corresponding sheet 6b.

The pair of alternating current introducing patterns 26 have a large number of through holes 33. The through holes 33 extend in both directions of the sheet 6b and the sheet 6c, and the corresponding AC introduction patterns 12, 1 formed on the sheet 6b.
Connected to 2. The ground pattern 27 has a sheet 6b.
A large number of blanks 34 corresponding to the blanks 20 provided on the ground pattern 13 are provided.

Each of the patterns formed on the sheets 6b and 6c is a thick film formed of a refractory metal such as tung ten or molybdenum. Next, the AC power supply circuit 9 will be described. First, the schematic configuration of the AC power supply circuit 9 will be described with reference to FIG. 9. The figure shows a circuit for supplying electric power to two Josephson elements 3. In this embodiment in which four Josephson elements 3 can be mounted, two sets of this circuit are formed. become. In the figure, an AC power supply circuit 9
Has an input side connected to an external AC power supply 41 provided separately from the Josephson device driving device 1, and an output side connected to a plurality of power supply input terminals of each Josephson device 3 through a path described later.

The external AC power supply 41 is composed of two AC power supplies 41a and 41b whose phases are different by 180 ° (half wavelength). The external AC power supply 41 supplies AC power of 1 GHz via a coaxial cable, for example, and its internal impedance (internal resistance 42) is, for example, 50Ω. On the other hand, the internal impedance 43 of each power supply load 3a in the Josephson element 3 is 3.1Ω, for example. An AC power supply circuit 9 is provided for impedance matching between the two.

In the AC power supply circuit 9, a λ / 4 impedance conversion circuit 44, 45, 46 composed of a resonant line having a length of 1/4 of the wavelength of the power supply current is directed from the external AC power supply 41 to the Josephson element 3. Are connected in a tree shape. First stage λ / connected to external AC power supply 41
Two second-stage impedance conversion circuits 45 are connected in parallel to the 4-impedance conversion circuit 44. Furthermore, two third-stage λ / 4 impedance conversion circuits 46 are connected in parallel to each second-stage impedance conversion circuit 45, and a power source load 3 a is connected to each third-stage impedance conversion circuit 46. Has been done. As a result, 1
The impedance of the λ / 4 impedance conversion circuit 44 in the second stage is set to 25Ω, and the λ / 4 impedance conversion circuit 4 in the second stage is set to 25Ω.
The impedance of 5 is 12.5Ω, and the impedance of the third stage λ / 4 impedance conversion circuit 46 is 6.25Ω.
Is set to. Each λ / 4 impedance conversion circuit 44,
45 and 46 are a pair of first and second conversion circuit patterns 47a, 47b, 48a, 48b, 49a and 49b, respectively.
It is composed of

With reference to FIGS. 5 to 8, sheets 6d, 6e, 6 for constituting the above-mentioned AC power supply circuit 9 are formed.
The circuit pattern formed on f and 6g will be described. 5 to 7, only a part of the circuit pattern, that is, the AC power supply circuit part shown in FIG. 9 is shown, and details are omitted. Therefore, the actual patterns are a pair of the patterns shown in FIGS.

In FIG. 5, the first ground circuit pattern 50 is formed on almost the entire surface of the sheet 6d. As shown in FIG. 6, on the sheet 6e, the first conversion circuit patterns 51a, 52a, 5 for forming the AC power supply circuit 9 are formed.
3a is formed. Here, at the input end 54,
One end of a conversion circuit pattern 51a forming the first-stage λ / 4 impedance conversion circuit 44 is connected. In addition,
The input side end portion 54 is connected to the through hole 33 of the corresponding AC introduction pattern 26 provided in the sheet 6c.

The conversion circuit patterns 52a and 52a forming the second stage λ / 4 impedance conversion circuit 45 branched from the other end of the first conversion circuit pattern 51a extend in an S shape in the middle. Each conversion circuit pattern 52a, 52
From the tip of a, the conversion circuit pattern 5 forming the third-stage λ / 4 impedance conversion circuit 46 in the opposite direction.
3a and 53a extend. Each conversion circuit pattern 53
In order to reduce the pattern area, a and 53a are bent in a C shape, and the tips are bent by approximately 270 °. A pair of output side end portions 55c are provided at the tip ends thereof. The output side end 55c is connected to the through hole 32 of the corresponding AC supply pattern 31 provided on the sheet 6c.

As shown in FIG. 7, the ceramic layer 6f includes first conversion circuit patterns 51a, 52a,
Second conversion circuit patterns 51b, 52b similar to 53a,
53b is the first conversion circuit pattern 51a, 52a, 53
It is formed at a position that vertically overlaps with a. The input side end 54a to which the conversion circuit pattern 51b is connected is the sheet 6
It is connected to the through hole 33 of the corresponding AC introduction pattern 26 provided in c.

Further, as shown in FIG. 8, a second ground circuit pattern 56 is formed on almost the entire surface of the sheet 6g. A number of through holes 57, 58, 59 are formed in the sheets 6d, 6e, 6f, and the first ground circuit pattern 5 is formed by these through holes 57, 58, 59.
0 and the second ground circuit pattern 56 are connected. In addition, the through holes 58 and 59 have circuit patterns 51a,
It is arranged on both sides of 51b, 52a, 52b, 53a, 53b.

Each pattern formed on each sheet 6d, 6e, 6f, 6g is a thick film formed by using a refractory metal such as tungsten or molybdenum.
Next, the insulating layer 5 will be described. As shown in Figure 1,
Inside the insulating layer 5, an internal circuit 6 made of a thin film of niobium is formed.
0 is formed. The internal circuit 60 mainly forms a signal wiring for exchanging signals with the Josephson element 3, but a part of the internal wiring 60 supplies power to the DC current supply circuit 8 and the AC power supply circuit 9. It is a power circuit 61 for supplying.

The surface of the insulating layer 5 is provided with a surface circuit 62 including a signal input / output pad 62a and pad portions 63 and 64 (FIG. 2) of the power circuit 61. The pad portion 63 is a coaxial cable 65 for supplying a DC bias current to the DC power supply circuit 8 from a DC power supply (not shown).
(FIG. 1), and is connected to the DC introduction pattern 11 of the seat 6b through the power circuit 61 and the through hole 19. On the other hand, the pad portions 64 are arranged at both ends of the pad portion 63, respectively, and are for connecting a coaxial cable for supplying AC power to the AC power supply circuit 9. The pad portions 64, 64
Is connected to the AC introduction pattern 12 of the seat 6b through the power circuit 61 and the through hole 19.

The surface circuit 62 and the pad portion 6 described above are used.
3 and 64 are all made of niobium. Each of the four Josephson elements 3 includes the four power supply loads 3a therein as described above (see FIG. 9), and each of them is arranged on the circuit board 1 so as to substantially correspond to the DC supply pattern 10 of the sheet 6b. It is installed. The DC power supply terminals of each power supply load 3a included in the Josephson element 3 are connected to the through holes 15 of the corresponding DC supply pattern 10 formed on the sheet 6b through the internal circuit 60 of the insulating layer 5. There is. Further, the AC power supply terminal of the Josephson element is connected to the through hole 18 of the corresponding AC supply pattern 17 provided on the sheet 6b via the internal circuit 60.

FIG. 9 shows an equivalent circuit of the above Josephson element driving device 1. In the figure, as described above, in each Josephson element 3, an AC current from the external AC power supply 41 passes through the AC power supply circuit 9 and forms a primary coil (not shown) that constitutes the transformer 70 of each power supply load 3 a. ) Is supplied to. On the other hand, a DC bias current is applied from an external DC power supply 71 to a secondary coil (not shown) of the transformer 70. The external DC power source 71 is the two AC power sources 41.
Two DC power sources 71a, 71 corresponding to a, 41b
b. Each of the DC power sources 71a and 71b includes the patterned lines 28a and 2 provided on the sheet 6c.
A bias current can be alternately applied to every other power supply load 3a via 8b.

In the DC power supply circuit 8 which supplies a DC bias current from the external DC power supply 71 to each power supply load 3a, an LC filter 72 as a low-pass filter is formed in the middle thereof. The LC filter 72 includes the pattern line 28 formed on the sheet 6c.
Each of the inductances a and 28b has and a capacitance generated when the pattern lines 28a and 28b face the ground pattern 13 provided on the sheet 6b. Therefore, this LC
The filter 72 is formed integrally with the DC power supply circuit 8 of the circuit board 2.

Next, the operation and effect will be described. The phase of the power supplied from each AC power supply 41a, 41b is 1
High voltage and low current differing by 80 °. This current is applied to the first and second conversion circuit patterns 47 of the first-stage λ / 4 impedance conversion circuit 44, which respectively constitute the AC power supply circuit 9.
a, 47b, second stage λ / 4 impedance conversion circuit 45
Of the first and second conversion circuit patterns 48a, 48b, and 3
It is amplified by the first and second conversion circuit patterns 49a and 49b of the stage λ / 4 impedance conversion circuit 46 and supplied to each power supply load 3a. Then, it is grounded from the ground terminal of the power supply load 3a through the ground circuit patterns 50 and 60.

Here, the impedance (50Ω) of the external AC power source 4 is set to 25Ω in the first stage λ / 4 impedance conversion circuit 44, to 12.5Ω in the second stage λ / 4 impedance conversion circuit 45, and the third stage. The λ / 4 impedance conversion circuit 46 provides 6.25Ω, which is the power load 3
Impedance conversion is performed between the impedance of a and 3.1Ω, and the impedance of the power supply load 3a and the impedance of the supplied power finally match.

Further, the first conversion circuit patterns 47a and 48 of the impedance conversion circuits 44, 45 and 46, respectively.
a, 49a and the second conversion circuit patterns 47b, 48b,
49b is parallelly fed (that is, the phase is 18
Since the electric power is different by 0 °), the ground noise can be reduced. Since the internal circuit 60 formed in the insulating layer 5 is arranged separately from the internal circuit 7 in which the AC power supply circuit 9 is formed, crosstalk with respect to signal property by the AC power supply circuit 9 is prevented. .

In this way, the time widths of output pulses based on the alternating currents from the alternating current power sources 41a and 41b supplied to the respective power source loads 3a and the mutual overlapping condition, that is, the timing, are determined by the direct current from the direct current power sources 71a and 71b. Adjusted by bias current. Therefore, each power load 3a
It is controlled stably. In the Josephson element driving device 1 described above, it is not necessary to provide a low-pass filter in each power source load 3a, and each power source load 3a can be miniaturized by that amount. A large number of can be mounted at high density.

Next, a method of manufacturing the above-mentioned circuit board 2 will be described. The insulating substrate 4 is formed of five ceramic green sheets that form the sheets 6a ... 6g. Each ceramic green sheet can be obtained by adding a suitable binder and a solvent to raw material powders such as mullite, silica, calcia, magnesia, and mixing them into a sludge shape, and forming this into a sheet shape by a well-known doctor blade method. A pattern in which a metal paste made of refractory metal powder such as tungsten or molybdenum is provided on each of the sheets 6b ... 6g after appropriate punching processing is performed on these ceramic green sheets to provide through holes and the like. Screen-printed into shape. Next, a plurality of ceramic green sheets are laminated in a predetermined order to form a ceramic green sheet laminate, which is fired at a temperature of about 1600 ° C. in a reducing atmosphere to form the insulating substrate 4 including the internal circuit 7. .

The insulating layer 5 is formed by a photolithography method including a step of applying a photosensitive polyimide paste on the insulating substrate 4 by a spin coating method. Then, the internal circuit 60 is formed by a physical vapor deposition method such as sputtering or vacuum vapor deposition so as to be a multilayer in the insulating layer 5, and is formed into a predetermined pattern by a photolithography method.

[0036]

In the circuit board for mounting the Josephson element according to the present invention, the low-pass filter for suppressing the mutual interference between the alternating current and the direct current bias current is formed integrally with the direct current power supply circuit in the insulating substrate. , The power can be stably supplied to the Josephson device by the multi-layer pulsating current power supply system, and the Josephson device can be mounted at high density.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a Josephson element driving device that employs an embodiment of the present invention.

FIG. 2 is a plan view of the drive device.

FIG. 3 is a plan view of a circuit pattern which constitutes the embodiment.

FIG. 4 is a plan view of a circuit pattern that constitutes the embodiment.

FIG. 5 is a plan view of a circuit pattern that constitutes the embodiment.

FIG. 6 is a plan view of a circuit pattern which constitutes the embodiment.

FIG. 7 is a plan view of a circuit pattern which constitutes the embodiment.

FIG. 8 is a plan view of a circuit pattern which constitutes the embodiment.

FIG. 9 is an equivalent circuit diagram of the drive device.

[Explanation of symbols]

 3 Josephson element 4 Insulating substrate 8 DC power supply circuit 9 AC power supply circuit 72 LC filter

Claims (1)

[Claims] 1. An alternating current power supply circuit for supplying two kinds of alternating currents having different phases to a Josephson device, and a Josephson device for adjusting the timing between output pulses of the two kinds of alternating current power. A DC power supply circuit for supplying a DC bias current, a low-pass filter formed integrally with the DC power supply circuit for suppressing mutual interference between the AC current and the DC bias current, and each circuit. And a circuit board for mounting a Josephson device, comprising: an insulating substrate that incorporates the low-pass filter and mounts the Josephson device.