JP3176382B2 - Film cable for equipment with superconducting elements - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film cable used in a superconducting element mounting apparatus for mounting a superconducting element such as a Josephson junction element.

[0002]

2. Description of the Related Art A Josephson junction device is known as a superconducting device which operates at a very high speed. However, the present applicant has first described an example of the configuration of an integrated circuit device in which the Josephson device is actually mounted and used. (JP-A-2-123774). In this superconducting element mounting apparatus, a circuit board 14 on which a superconducting element 12 is mounted is set in a cryostat 10 having a Dewar bottle structure as shown in FIG. 6, and this circuit board 14 and an external circuit are connected by a film cable 16. It has a configuration to do. The superconducting element 12 is immersed in liquid helium and maintained at a very low temperature. The outer wall of the cryostat 10 is formed by a vacuum heat-insulating housing 18 in order to enhance the heat insulating property.
A very thin film cable 16 of about 1 mm is passed through the heat insulating housing 18 to connect the superconducting element 12 in the cryostat 10 to an external circuit. The reason for using the thin film cable 16 is to maintain the heat insulation of the cryostat 10, and to shorten the signal propagation time by connecting an external circuit as close as possible to the superconducting element 12, thereby reducing the speed of the superconducting element. This is for fully exhibiting.

As described above, in the superconducting element mounting device, signals are transferred by a film cable 16 installed through the outer wall of the cryostat 10, and the film cable 16 is made of an insulating film having electrical insulation such as polyimide. A signal line and a ground layer are formed by using a thin film conductor, and the arrangement of the signal line and the insulating film has a configuration suitable for high-speed signal propagation such as a strip line structure or a coplanar structure.

FIG. 7 shows a film cable 16 and a circuit board 1.
4 shows a planar arrangement at a connection portion with No. 4. The connection terminals provided on the circuit board 14 can be arranged in various ways, but the connection terminals are arranged along the side edge of the circuit board 14, and the contact terminals are formed on the film cable 16 according to the arrangement of these connection terminals. The connection is made at the side edge of the circuit board 14. In some cases, a large number of connection terminals are required because a plurality of superconducting elements 12 are mounted on the circuit board 14 or a wiring pattern is formed at a high density. Place connection terminals on the four side edges of each and connect with film cables from each side edge,
As shown in FIG. 7, connection terminals are arranged in a plurality of rows on the side edge of the circuit board 14.

[0005]

In the circuit board 14 having the connection terminals arranged in a plurality of rows as described above, it is necessary to appropriately set the arrangement of the connection terminals connected to the signal lines and the connection terminals connected to the ground layer. . That is, in the circuit board 14, the signal lines and the ground layer are formed in different layers, but the signal lines are
The ground layer is formed on the surface side of the circuit board 14.
Are formed over almost the entire surface of the circuit board 14 in the inner layer of the circuit board 14. Of the connection terminals arranged in a plurality of rows, the connection terminals on the row near the outer edge of the circuit board 14 are connection terminals connected to the ground layer (hereinafter, grounding The connection terminals in the inner row must be terminals connected to signal lines (hereinafter, referred to as signal connection terminals 20b). Since the signal connection terminal 20b communicates with the superconducting element, the signal connection terminal 20b extends from the outer edge of the circuit board 14 toward the center of the circuit board 14 as a planar arrangement. Therefore, the ground connection terminal 20a is arranged inside the signal connection terminal 20b. Then, the ground connection terminal 20
This is because the signal lines must be arranged so as to avoid “a”, which hinders the arrangement of the signal lines.

As described above, the connection terminals 20 are connected to the circuit board 14.
Are arranged in parallel, the arrangement of the signal connection terminals 20b and the ground connection terminals 20a is limited. As a result, the contact terminals of the film cable 16 connected to the circuit board 14 are also connected to the signal connection terminals 20b and the ground connection terminals 20a. Therefore, it is necessary to arrange the signal lines and the ground layers on the film cable 16 side appropriately. The present invention thus provides a suitable superconducting element that can arrange signal lines and the like without being affected by the arrangement of the contact terminals when providing the contact terminals on the film cable based on the arrangement of the connection terminals on the circuit board. An object of the present invention is to provide a film cable for an apparatus.

[0007]

The present invention has the following arrangement to achieve the above object. That is, a contact terminal arranged on the connection end side in the same arrangement as a connection terminal provided on a side edge of a circuit board on which a superconducting element is mounted, and a signal contact terminal connected to a signal line and a ground contact connected to a ground layer In a film cable for a superconducting element mounting device having terminals, a signal line connected to the signal contact terminal and a ground layer connected to the ground contact terminal are separated by another layer in the thickness direction with an electrically insulating layer such as polyimide interposed therebetween. And a layer close to a surface contacting the circuit board is a ground layer. Further, a concave portion communicating with the ground layer or the signal line is formed in a depth direction from a surface contacting the circuit board, and the ground layer or the signal line is exposed on the bottom surface in the concave portion to respectively provide a ground contact terminal and a signal contact terminal It is characterized by having. Further, a film in which a ground layer is not provided within a predetermined width from the outer peripheral edge of the film, and the portion within the predetermined width is formed only of an electrically insulating layer such as polyimide is effectively used.

[0008]

The ground layer and the signal line formed in the film cable are formed as separate layers, and the ground layer is arranged on the film surface side of the circuit board in contact with the connection terminal, and the signal line is separated from the connection terminal. By arranging, it is possible to set the signal line without disturbing the arrangement position of the ground contact terminal when the signal contact terminal is arranged on the edge side of the connection end of the film cable and the ground contact terminal is arranged inside. Become. Further, by forming the outer peripheral edge portion only with the electrical insulating layer, it is possible to obtain a film cable in which heat inflow from the film end surface is suppressed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an explanatory view showing an embodiment of a film cable for a superconducting element mounting apparatus according to the present invention. The film cable 16 of this embodiment is a film cable used when connecting to the circuit board 14 on which the connection terminals 20 are arranged in two rows, similarly to the film cable shown in FIG. As shown in the figure, the film cable 16 includes a polyimide film 16a, a ground layer 16b, and a polyimide film 1 in this order from the upper layer.
6a, the signal line 16c, and the polyimide film 16a. The ground layer 16b is provided over substantially the entire surface of the film cable 16 by a thin film conductor. The polyimide film 16a is provided as an electrical insulating layer. The polyimide film 16a acts as a microstrip line structure for the signal line 16c, and the polyimide film 16a provided between the signal line 16c and the ground layer 16b must be formed to a predetermined thickness. Thereby, a characteristic impedance of, for example, 50Ω can be realized.

On the connection end side of the film cable 16 to the circuit board 14, contact terminals for connecting to the connection terminals of the circuit board 14 are formed. In the embodiment, a contact probe formed by projecting a terminal from the board surface is used as a connection terminal on the circuit board 14 side, and the contact terminal extends from the upper surface of the film cable 16 to the ground layer 16b and the signal line 16c at each contact probe position. It is formed by providing a concave portion having a depth that can communicate. In FIG. 1, the recess 30b is a recess leading to the ground layer 16b, and the ground layer 16b is exposed on the inner bottom surface of the recess 30b. The recess 30c is a recess leading to the signal line 16c below the ground layer 16b.
A predetermined signal line 16c is exposed on the inner bottom surface of 0c.

As described above, the connection terminals provided on the circuit board 14 are electrically connected to the signal lines 22 and the ground layer 24 of the circuit board 14 as contact probes as shown in FIG. 1, and are embedded in the board. As described above, the film cable 16 is brought into contact with the ground layer 16b and the signal line 16c on the inner bottom surfaces of the concave portions 30b and 30c of the film cable 16,
Are formed by projecting the contact ends 21a and 21b in the depth direction. In the film cable 16, as described above, the ground layer 1
6b is formed in the upper layer and the signal line 16c is formed in the inner layer, so that the contact end 21b connected to the signal line 16c is
It goes deeper than a. The abutment end 21b will therefore enter through the ground layer 16b,
The concave portion 30c is formed to have a larger diameter than the outer diameter of the contact end 21b in order to prevent a short circuit with the contact end 21b. The contact probe has a contact end 21a as shown in FIG.
21b may have different protruding lengths in accordance with the depths of the recesses 30b and 30c.
1a and 21b are urged in a direction protruding from the substrate surface to support the substrate so as to be able to protrude into the substrate.
You may comprise so that it can enter until it abuts on the inner bottom surface.

FIG. 2 is an explanatory view showing a state where the circuit board 14 and the film cable 16 are connected in the superconducting element mounting device. The film cable 16 is clamped between the support 26 supporting the circuit board 14 and the circuit board 14, and the contact ends of the ground connection terminal 20 a and the signal connection terminal 20 b are pressed against the ground layer and the signal line of the film cable 16. The circuit board 14 and the film cable 16
Are connected. Circuit board 14 and film cable 16
When it is set, it is necessary to align the connection terminals of the circuit board 14 with the contact terminals of the film cable 16. In this embodiment, guide pins are provided upright at the corners of the support 26 , guide holes for inserting the guide pins are provided in the circuit board 14 and the film cable 16, and the guide pins are aligned with each other. The circuit board 1 is fastened by tightening the nut at the position of the provided guide pin.
4 fixed to the support 2 6 simultaneously film cable 1
6 is pinched.

FIG. 3 is a plan view showing the arrangement of the contact terminals in the film cable 16 described above. The film cable 16 has one end connected to the circuit board 14 and the other end connected to an external circuit. At the connection end to the circuit board 14, as shown in FIG. According to the arrangement of the ground connection terminals 20a and the signal connection terminals 20b of the circuit board 14, the rows on the edge side are signal contact terminals 40c connected to the signal lines 16c, and the inner rows are the ground contact terminals 40b. Is defined as In this embodiment, the signal line 1
6c is provided below the ground layer 16b, so that the signal line 16c can be formed without being hindered by the ground contact terminal 40c even if the signal contact terminal 40c is located on the edge side of the ground contact terminal 40b. it can. If the position of the signal line 16c and the ground layer 16b is reversed by the film cable 16, the signal line 16c is connected to the ground layer 16b.
If it is set to a higher layer, the concave portion 30c crosses the signal line 16c at the position of the ground contact terminal 40b, and the ground contact terminal 40b hinders the arrangement of the signal line 16c. Therefore, when the ground contact terminal 40b is provided inside the signal contact terminal 40c in the film cable 16, the signal layer 16c provided in the film cable 16 is preferably set to a lower layer than the ground layer 16b.

The film cable 16 of the above embodiment is used.
Although the ground contact terminals 40b and the signal contact terminals 40c are arranged side by side in two rows at the edges, the ground connection terminals 20a and the signal connection terminals 20b may not be arranged in the same row depending on the circuit board. 1
In some cases, the arrangement of the ground contact terminal 40b and the signal contact terminal 40c in FIG. 6 may be as shown in FIG. 4 or FIG. Also in these cases, the ground contact terminal 40b is defined so as to be located inside the signal contact terminal 40c as in the above example, so that the position of the signal line 16c in the film cable 16 is lower than the ground layer 16b. , The ground contact terminal 40
The signal line 16c can be arranged without being affected by the arrangement of b. The arrangement of the connection terminals arranged on the circuit board 14 can be set in various patterns other than the above,
As described above, the signal line 1 in the film cable 16
By setting the layer positions of 6c and the ground layer 16b, the signal line 16c can be formed without being affected by the ground contact terminal 40b, and the signal line 16c can be formed with high density.

The ground layer 16b formed by the film cable 16 is preferably set as thin as possible under conditions that do not impair the signal transmission characteristics. This is because the smaller the cross-sectional area of the film cable 16 is, the better the heat inflow to the cryostat 10 is, and the heat inflow from the ground layer 16b having a high thermal conductivity acts greatly. In the embodiment shown in FIG. 1, the ground layer 16b is provided entirely in the plane of the film cable 16 and the end of the ground layer 16b is exposed at the outer end surface of the film cable 16b. In order to suppress this, it is effective to use only an electrically insulating layer such as polyimide without providing the ground layer 16b within a predetermined width from the outer peripheral edge of the film cable 16. As described above, the heat inflow from the end face of the film cable 16 can be suppressed by using the peripheral portion of the film cable 16 as the electrical insulating layer. As described above, the present invention has been described variously with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and it is needless to say that many modifications can be made without departing from the spirit of the invention. That is.

[0016]

According to the film cable for a superconducting element mounting apparatus according to the present invention, as described above, by arranging the ground layer and the signal line in the film cable,
The signal lines can be formed without being affected by the arrangement of the contact terminals provided on the film cable. The signal lines in the film cable can be easily formed, and the signal lines can be easily arranged at a higher density. It has a significant effect such as becoming.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a connection state between a circuit board and a film cable.

FIG. 2 is an explanatory diagram showing an arrangement of a film cable in the superconducting element mounting device.

FIG. 3 is an explanatory view showing an example of arrangement of contact terminals in a film cable.

FIG. 4 is an explanatory diagram showing an example of arrangement of contact terminals in a film cable.

FIG. 5 is an explanatory diagram showing an example of arrangement of contact terminals in a film cable.

FIG. 6 is a sectional view showing a superconducting element mounting device.

FIG. 7 is an explanatory diagram showing a connection portion between a circuit board and a film cable.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Cryostat 12 Superconducting element 14 Circuit board 16 Film cable 16a Polyimide film 16b Ground layer 16c Signal line 20a Ground connection terminal 20b Signal connection terminal 21a Contact end 21b Contact end 22 Signal line 24 Ground layer 26 Support 30b Recess 30c Recess 40b Ground contact terminal 40c Signal contact terminal

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fumio Miyagawa 711 Rita Kurita-sha, Nagano-shi, Nagano Prefecture Inside Shinko Electric Industries Co., Ltd. (56) References JP-A-1-298608 (JP, A) JP-A-63-177764 (JP, U) JP-A-1-503665 (JP, A) (58) Fields surveyed ( Int.Cl. ⁷ , DB name) H01L 39/02-39/04 H01L 23/00 H01R 4/68 H05K 1/00

Claims (3)

(57) [Claims] 1. A contact terminal arranged on the connection end side in the same arrangement as a connection terminal provided on a side edge of a circuit board on which a superconducting element is mounted, and connected to a signal contact terminal connected to a signal line and a ground layer. In a film cable for a superconducting element mounting device having a ground contact terminal to be connected, a signal line connected to the signal contact terminal and a ground layer connected to the ground contact terminal are formed in a thickness direction with an electrically insulating layer such as polyimide interposed therebetween. A film cable for mounting a superconducting element, wherein the film cable is formed as a separate layer, and a layer adjacent to a surface contacting the circuit board is a ground layer. 2. A concave portion communicating with the ground layer or the signal line is formed in a depth direction from a surface side in contact with the circuit board, and the ground layer or the signal line is exposed on a bottom surface of the concave portion to form a ground contact terminal. 2. A film cable for a superconducting element mounting device according to claim 1, wherein said film cable is a signal contact terminal. 3. The film according to claim 1, wherein a ground layer is not provided within a predetermined width from the outer peripheral edge of the film, and the portion within the predetermined width is formed only of an electrically insulating layer of polyimide or the like.
The film cable for a superconducting element mounting device as described in the above.