FI106754B - Contact-furnished pickup with layer structure and method for creation of the contact points - Google Patents

Abstract

This publication describes a contact-furnished pickup 1' with layer structure and a method for creating the contacting of the pickup. According to the invention, the contacts 5' are formed on the side surface 7 of the pickup by utilisation of laser-based metallisation technique, by vaporisation, or by utilisation of another suitable deposition technique. As a result of the new method of contacting, the size of the pickup 1' can be reduced and the pickup 1' can be connected to a circuit card by utilisation of surface mounting technique. <IMAGE>

Description

106754

The present invention relates to a contacted sandwich sensor according to claim 1.

The invention also relates to a method for carrying out contacting.

The invention is intended to be used for making electrical contacts in layered semiconductor structures, mainly sensors, which are fabricated at once in tens or hundreds of pieces on a plate-like substrate. At the end of the manufacturing process, the board is usually cut into saw-15 clubs as independent sensors. Each independent sensor comprises a plurality of conductive layers extending to the sawn surfaces. The conductive layers are galvanically separated.

20 Contacts to external circuits are usually made through separate contact areas. The contact area is a metallized, usually rectangular, area to be exposed. electrical wires from the ronic plate can be attached.

• · · ♦. ♦ ··. The contact area within the sensor is electrically connected to suitable parts of the sensor. Conventional structure is shown '!!! 1. This corresponds to the prior art and is known e.g.

;;; U.S. Patent No. 4,979,727.

• ♦ «» »·

Contact areas such as those described above are located in the sensor at the same contact plane parallel to the plate-like substrate, since this makes it easy to fabricate the contact areas prior to cutting the sensor plate, e.g., by photolithography and vacuum V; 'evaporation. However, the contact level reserved for the contact areas greatly increases the overall dimensions of the sensor. 35 Since the size of the sensor is directly proportional to the unit cost of the sensor, it is important to make the sensor area as small as possible. Thus, the existence of prior art contact levels of ·: ·· * increases the cost of the sensor. Another drawback is the difficulty in forming electrical connections from inside the 106754 2 sensor to the contact areas of the contact plane, since the wiring of the conductors to other conductive parts of the sensor must be prevented in one way or another.

The object of the present invention is to eliminate the drawbacks of the above-described technique and to provide a completely new type of contacted sandwich sensor and a method for implementing the contacting.

The invention is based on the fact that the contacts are formed on the vertical surfaces of the conductive layers of the sensor which are formed when the sensor is finally removed from the plate structure. In other words, it is essential for the invention that the conductive film regions are made on surfaces other than the original planar surfaces of the plate-like or disc-like starting materials.

More specifically, the sandwich sensor according to the invention is characterized in what is stated in the characterizing part of claim 20.

The process according to the invention, in turn, is characterized by what is stated in the characterizing part of claim 2.

• · «· 25 ♦ · ♦

The invention provides considerable advantages.

The surface area of the sensor can be reduced by up to a third, whereby the sensor becomes cheaper accordingly. This fact is ... 30 very important if the sensor is mass-produced.

*; *; * Second, the structure of the sensor is simplified because there is no need to bring wires outside the sensor. A third advantage is that: *: ** the sensor structure according to the invention can be connected to a circuit board, e.g., by means of a surface connection technique, where the conventional solution is' .'35 wiring.

The invention will now be further explored by way of an exemplary embodiment in accordance with the accompanying drawings.

3 106754. Fig. 1 is a perspective view of a prior art electrical contact solution for a sensor.

Figure 2 likewise shows a perspective view of one sensor according to the invention.

Figure 3 is a top plan view of one plate-like substrate from which the sensor utilized in accordance with the invention is removable.

10

Figure 1 shows a prior art sensor 1 comprising a first semiconductor layer 2 and a second semiconductor layer 4 and an intermediate insulating layer 3. Contact areas 5 are formed on the contact plane 6. The contact plane 6 is structurally an extension of the second semiconductor layer 4 is brought to contact plane 6 within the antenna structure.

The contacting method according to the invention is shown in Figure 2.

* ··· 'A typical sensor piece 1' consists of two or more conductive semiconductor layers 2 'and 4' provided with contact areas 5 'to the vertical side of the sensor piece 7. Layer 3' is an electrical insulating layer between semiconductor layers 2 '25 and 4'.

• · «♦ ♦ *« · · «

Fig. 3 shows a typical sandwich matrix sheet 8, whose matrix elements 1 'represent individual sensors. Sensors 1 'are typically mechanically removed from plate 8 by cutting along lines 9 and 10. The laser can also be used to detach the sensors 1 '.

• ♦. *: '· The solution of Fig. 2 does not have the prior art * · ·. * · *. and the contacts 5 'are made directly to the side surface 7 of the 35 sensors using, for example, laser assisted metal spin bonding processes. By side surface 7 is meant the surface that is exposed when the sensor pieces 1 'are sawed off the layered discs 8 of Fig. 3 along lines 9 and 4 106754 10.

The contact areas 5 'are made chip-by-chip (e.g., laser-assisted metallization), described e.g. in Seu-5, R. Solanki et al., "Low Temperature Refractory Metal Film Deposition", Appl. Phys. Lett., 41, (11), 1 Dec 1982 10 R.M. Osgood et al., "Laser Microchemistry for Direct Writing of Microstructures," Proc. SPIE, 385, 112-117, 1983

Dieter Bäuerle, Laser-Induced Chemical Vapor Deposition, Laser Processing and Diagnostics, ed. D. Bäuerle, Springer 15 Verlag, 1984, T. Cacouris et al., "Laser Direct Writing of Aluminum Conductors", Appl. Phys. Lett., 52, (22), 30 May 1988 20 For metallization, the probe blocks 1 'are introduced into a sealable chamber which can be vented with a suitable gas and has an upper surface which is transparent to laser light. The sensors l * are guided one by one:: one after the other to the laser beam so that the focus of light falls ··· on one of the regions 5 'of the conductive surface 2'. The illuminated spot 5 '• · · · 25 is heated by light and the gas in the chamber which contains the desired metal, such as aluminum, gold or

»· I

nickel, pyrolyses (or photolyses) at a hot point 5 '. Thus, the metal is reduced to form a contact region 5 'on the semiconductor surface. The contact area typically has a diameter of 0.1 to 0.5 mm and a metallization thickness of 0.1 to 0.5 µm.

The temperature of the focal point 5 'can be raised by the laser • · at a suitable high, typically a few hundred degrees Celsius, so that the metal can have a good electrical contact half. ». ···. the guide rail. The focus is then shifted to other areas' · '· 35 5' and the process is repeated.

• · ·

Alternatively, the metallization 5 'may be, for example, steamed, sputtered, or electrolytically or auto-grown on the sawn side of the structure and subsequently metallized, for example by laser, photosensitive and patterned polymeric layer, or mechanically etched, e.g. by grinding the metallization out of desired places. Electrolytic growth can be used to metalize all conductor surfaces of the sensor throughout. The insulation layer is automatically left without metallization. Unless metallization is otherwise disadvantageous, this process is the single-10th most common method of electrolytic contact metal cultivation.

Alternatively, the metallization may be performed directly through a mechanical or other mask at desired locations. The mask can be made, for example, of a photosensitive polymer by exposing and developing the desired sites, or by patterning, for example, a polyimide layer with an excimer laser or the like.

The electrical contacts can also be made on the side surface of the structure, for example by an eutectic gold-silicon alloy, which can also be used to attach metal probes or the like to the side of the sandwich structure. Heating and compression make the alloy a bond between the semiconductor and • 4 ·. · · Metal.

• · · • ♦ • «« • 4 Ί 4 4 »· 4 • · · • 44 4 4 4« • 4 4 • * 4 4 4 * · • • • V «*« «. «· • * · •« ««

Claims (9)

6 106754 A semiconductor sensor (1 ') comprising electrical contacts (5') made by depositing planar conductor and 5 dielectric layers (2 ', 3', 4 ') into a matrix plate (8), each matrix element being on the surface of the plate (8). in a direction perpendicular to the plane into an independent sensor (1 ') having vertical surfaces comprising a plurality of galvanically separated conductive layers, characterized in that the electrical contacts (5') of the sensor (1 ') are located on those conductive vertical surfaces (7) are formed when the sensor (1 ·) is removed from the plate (8). Method for forming electrical contact with a semiconductor sensor structure 15 made by depositing planar conductor and dielectric layers into a matrix plate (8), each matrix element being separable perpendicular to the surface of the plate (8) by a plurality of vertical surfaces 20 galvanically separated conductive layers, characterized in that the electrical contacts (5 ') of the sensor (1') are formed on the conductive vertical surfaces (7) of the sensor (11) which are formed when the sensor (11) is removed. plate (8). • · • «« «·« • «« «; ***; Method according to Claim 2, characterized in that the contacts (5 ·) are made by laser-assisted • · · ·. growth process. • · · · · · · · · · · · · Method according to claim 3, characterized. . 30, inserting the sensor (1 ·) into a closed chamber having a suitable metal-containing gas and having a light-transmitting surface · · * · 1 1 and a side surface (7) of the sensor (1 '). heated: 1 · 1: by a laser beam at the desired position (5 '), whereby the desired metal; ** ·; pyrolyses at the heated point (5 '). • · · • 35 «·« · · Method according to claim 2, characterized in that the contacts (51) are made by evaporation. 106754 Method according to Claim 2, characterized in that the contacts (5) are made by sputtering. Method according to claim 2, characterized in that the contacts (5) are made by electrolytic growth. A method according to claim 2, characterized in that the contacts (5) are made autocatalytically. 10 Method according to Claim 2, characterized in that the contacts (51) are made, for example, through a mask of photosensitive polymer at the desired locations by exposing and creating the desired apertures in the mask. «« «« «•« «« «» M «t *» «•« • «« (I t · »» ♦ * ♦♦♦ • · • · ··· •• · • ♦ ♦ ♦ ♦ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 · · «· · · 106754