JPS598384A - Silicon wiring substrate - Google Patents

Abstract

PURPOSE:To obtain the silicon wiring substrate on which a high density mounting of low temperature device elements can be performed by a method wherein both a row of pins and a row of sockets for microconnector are provided on the same silicon substrate. CONSTITUTION:A row of microscopic holes are formed on silicon single crystal substrates 8a and 8b having the face 100 respectively by performing a selective etching, and a microsocket 10 is formed by adhering said two substrates in such a manner that the center of each row of microscopic hole will be coincided with each other. Then, after a niobic film has been formed on the substrate by performing a sputtering method, a required niobic wiring 12 is formed by performing an etching. Then, a micropin 9 is soldered using an indium alloy. The wiring substrate thus constituted is laminated in such a manner that the row of pins and the row of sockets are connected to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silicon wiring board suitable for mounting electronic devices used at low temperatures, such as Josephson computers.

Conventional wiring boards have been used with electronic devices mounted on them at around room temperature, so various organic printed boards have been used that have a higher coefficient of thermal expansion than semiconductors or metals. Therefore, even if you try to use a low-temperature electronic device such as a Josephson element mounted on a conventional organic printed wiring board, there will be problems due to a mismatch in the coefficient of thermal expansion between the silicon device tip and the wiring board, resulting in solder connections. The parts were destroyed and it was not put into practical use. Ceramic wiring boards and metal wiring boards have been used as a solution to this problem, but even these have thermal expansion coefficients that do not strictly match those of silicon devices/chips, so a wiring board with even higher reliability has been desired. .

As a conventional technique that meets this demand, a silicon wiring board for mounting Josephson elements is known. In this silicon wiring board, all mounting board materials including the board on which the Josephson element is mounted are made of silicon, and the structure is as shown in FIG. 1. In Figure 1,
1 is a Josephson element, 2, 3, and 4 are silicon wiring boards, 5 is a micro connector bin (hereinafter referred to as a micro bin), and 6 is a silicon substrate having a micro connector socket (hereinafter referred to as a micro socket) 7. It is.

Silicon wiring ゛Only the microbins 5 made of platinum (Pt) are soldered to the substrates 3 and 4, and the other silicon wiring substrate 2 is soldered perpendicularly to the silicon substrate 3, which itself has microbins. There is. And 2
The silicon wiring boards 3 and 4 are connected to each microbin 5.
are connected to each other by inserting them into the micro sockets 7 of the silicon substrate 6.

However, in the known silicon wiring board as shown in FIG. Three-dimensional mounting of elements and substrates, such as closely stacking elements and substrates at high density, has not been possible. Furthermore, since the silicon wiring board 2 with the Josephson element 1 is attached perpendicularly to the silicon wiring board 3, silicon is extremely susceptible to mechanical and thermal shocks due to the lack of mechanical strength of silicon. The strengths of the wiring board were not fully brought out.

It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide a new silicon wiring board 'fc for ultra-high-speed computers that allows low-temperature device elements to be laminated at high density and has excellent electrical and mechanical properties. do.

This objective can be achieved by providing both a micro connector pin row and a socket row on the same silicon substrate. In this case, microbins made of Pt or the like may be used as the bin array, or by growing silicon whiskers on a silicon single crystal substrate and using this, an ultra-high density microconnector can be realized. The present invention will be explained in detail below with reference to FIGS. 2 to 4.

FIG. 2 shows the first embodiment of the present invention, where 8 is (100)
A silicon single-crystal substrate with a flat surface, a microbottle made of 9 digits, 10 a microsocket filled with mercury, and 11 a hole provided for coolant circulation. Microbin 9
and the micro socket 10 are each made of a silicon single crystal substrate 8.
It is connected to the upper wiring conductor 2, and if necessary, to a Josephson element (not shown).

The micro bottle 9 and the micro socket 10 are connected and fixed by solidification of mercury at low temperatures. The example shown in FIG. 2 was manufactured by the following method. First, a row of pores is created in a (100) simple crystal substrate of silicon by a known selective etching method for crystal planes, and the centers of the pores of the two silicon substrates 8a and 8b coincide with each other. A micro socket 10 was produced by attaching them face to face with a low-temperature adhesive. The reason why the silicon substrates were pasted together is that the fine pores in each silicon substrate tend to have a trapezoidal cross section as shown in FIG. 4, so if only one silicon substrate was used, it would be difficult to function as a mercury reservoir. Next, a Nb film is formed on the silicon single crystal substrate by sputtering, and then the required Nb wiring is formed by etching.Then, the surroundings of the microhole of the microsocket 10 and the microbin are soldered at the planned positions. A Pd (palladium) film was deposited to improve adhesion with solder. Thereafter, a micro-bin 9 made of Pt having a height of 200 μm and an outer diameter of 150 μm was soldered with an In (indium) alloy to obtain the silicon wiring board 8 of this example.

FIG. 3 shows a second embodiment of the present invention, which has a three-layer structure. 13a and 13b are (111) plane silicon single crystal substrates, 13C is an (IIO) plane silicon single crystal substrate, 14 is a microbin using silicon whiskers grown in the (111) plane, and 15 is a low melting point alloy. It is a filled micro socket. The example shown in FIG. 3 was produced by the following method. First, a fine hole of 50 μmφ for a micro socket was made by etching9 on each silicon (111) simple crystal substrate 13a, 13b with a diameter of 2 inches and a plate thickness of 0.251111, and then only the planned position of the micro pin row was left on the substrate surface. was coated with a Sin film. Next, A11 (*) was evaporated at the position of the microbin, and the diameter was 2Qpm using the VLS method.
After growing silicon whiskers with a height of about 300 pm on the substrate, the height of the silicon whiskers was adjusted to 250 μm using a carbon dioxide laser. After that, an At (aluminum) film is formed on the silicon whisker pins and the surface of the substrate using the ion blasting method, and the required At wiring is created by dry etching, and then a low melting point solder is applied around the microhole for the micro socket. Next, a Cr (chromium) film was added to improve the wettability with C.
A u′ (copper) film was deposited. On the other hand, a silicon (110) simple crystal substrate 1 with a diameter of 2 inches and a thickness of 0.25 m
3C is the silicon (111) simple crystal substrate 13a.

-side 10 so that the center position coincides with the microhole 13b.
A large rectangular micropore with a size of 0 μm is created by etching, and the silicon (111) simple crystal substrates 13a, 1 are placed on both sides of the thus obtained silicon (110) simple crystal substrate 13c.
A silicon wiring board 13 of the second embodiment was obtained by pasting 3b.

The reason why the silicon (111) plane plate and the silicon (110) plane plate were used separately in the second embodiment is as follows. First, in the VLS method, the silicon (111) surface (
This is because silicon whiskers grow only in the 111) direction. Second, the silicon (110) plane has the highest selective etching rate among silicon crystals;
Since the 111) surface is the smallest, a low melting point alloy reservoir can be easily created by combining these surfaces and changing the hole diameter. For the same reason, a (100) plane silicon single crystal substrate can be used instead of a (110) plane silicon single crystal substrate.

FIG. 4 shows a third embodiment, which has a two-layer structure. 16a
16b is a silicon (111) simple crystal substrate, 16b is a silicon (110) simple crystal substrate, 17 is a microbin using silicon whiskers grown on the (111) plane, and 18 is a microphone socket filled with a low melting point alloy. be. The silicon wiring board 16 of this embodiment is made of silicon (110).
The micropores of the simple crystal substrate 16b have a trapezoidal cross section, and the silicon single crystal substrate 16a of the (111) plane has a (11
It was manufactured in the same manner as in the second embodiment, except that only the piece 9AK of the silicon single crystal substrate 16b of the 0') plane was bonded.

As explained above with reference to various embodiments, the silicon wiring boards 8, 13, and 16 of the present invention have both micro pin rows and micro socket rows on the same board, so the positions of the pin rows and socket rows are By combining two types of materials with opposite relationships, it is possible to easily stack silicon wiring boards in close contact with each other, which overcomes the fragility of silicon substrates, has high density and excellent mechanical strength, and is suitable for low-temperature device mounting. can make a significant contribution to Note that even if silicon wiring boards are stacked, the cooling medium will freely flow through the holes 11 in the center of the boards, so that the cooling efficiency of the elements will not be reduced in any way. Furthermore, a silicon single crystal substrate 13a is used as micro pins 14 and 17.

By using the silicon whiskers grown in 13b and 16a, the diameter of the pins can be reduced to submicrons, thereby realizing an ultra-high-density microconnector. Note that micro pins using silicon whiskers can be applied not only to silicon wiring boards but also as micro connectors for cables and the like.

As described in detail above, the present invention contributes to the miniaturization of ultra-high-speed computers using future low-temperature devices that require particularly high-density packaging.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a mounting form using a conventional silicon wiring board, FIG. 2 is a perspective view showing a first embodiment of the present invention, and FIG. 3 is a sectional view showing a second embodiment. FIG. 4 is a sectional view showing the third embodiment. In the drawing, 8.13 and llj silicon wiring board, 8a and 8bt
i Silicon (100) simple crystal substrate, 13a, 13b and 16a are silicon (111) simple crystal substrates, 13c and 16b are silicon (110) simple crystal substrates, 9 is a microbin made of PT, 14 and 17 are made of silicon whiskers Micro pins, 10, 15 and 18 are micro sockets, 11 is a refrigerant flow hole, and 12 is a wiring conductor. Patent applicant Nippon Telegraph and Telephone Public Corporation representative Patent attorney Shibe Mitsuishi (and 1 other person) Figure 1 Figure 2

Claims (5)

[Claims] (1) A silicon wiring board that has a micro connector pin row and a micro connector microhole row on the same silicon substrate, and each of these pin rows and the microhole row is connected to a wiring conductor on the silicon substrate. (2) The above micro connector pins are made of silicone (11
1) The silicon wiring board according to claim 1, wherein the pin is formed by covering the surface of a silicon whisker grown on a simple crystal substrate with a conductor. (3) The silicon substrate is a substrate formed by laminating a first layer substrate of a (111) plane silicon single crystal and a second layer substrate of a (110) plane or (100) plane silicon crystal, and the micro connector The vial is a vial made by covering the surface of silicon whiskers grown on the first layer substrate with a conductor. 2. The silicon wiring board according to claim 1, wherein the silicon wiring board is made up of microholes in the second layer board that are combined with each other. (4) The silicon substrate is a first layer substrate and a third layer substrate made of a (111) plane silicon single crystal, and a second layer substrate made of a (110) plane or α00) plane silicon single crystal which is bonded between these two substrates. The pin is made by covering the surface of silicon whiskers grown on each of the first layer and third layer substrates for the micro connector with a conductor, and the micro holes for the micro connector are formed on the first layer and the third layer substrate. and a fine hole in the third layer substrate whose centers are aligned with each other, and a fine hole in the second layer substrate which has a diameter larger than these fine holes and whose centers are aligned with each other. Silicon wiring board. (5) The silicon wiring board according to claim 1, 2, 3, or 4, wherein the silicon substrate has a gap for coolant circulation approximately in the center thereof.