DE2207012C2 - Contacting semiconductor device with pN-junction by metallising - with palladium or nickel, alloying in window, peeling and gold or silver electroplating - Google Patents

Abstract

Prodn. of contacts on semiconductor devices (1) with pn-junction(s) involves making window(s) (6, 8) to the semiconductor through an insulation film (4) and/or passivation film (7); deposition of an adhesive film (10) over the entire surface and peeling this off on the insulation film and/of passivation film; and enhancing the adhesive film (10) with a Au or Ag film (11). The adhesive film may consist of Pd or Ni. Pd is deposited from the vapour phase in a thickness of 50-100 mm; Ni is deposited by an electroless or a d.c. or a.c. electroplating process in a thickness of 50-100 nm; Pd or Ni film is alloyed in the window before peeling; and Pd or Ni film is electroplated to a thickness of 1-100 microns.

Description

The invention relates to a method for contacting semiconductor components with at least one pn junction according to the preamble of claim 1 or according to the preamble of claim 2.

The preambles of claim 1 and claim 2 each describe a method for making contact of semiconductor components, as they are known from DE-OS 19 27 646. In this DE-OS 19 27 646 is only in the embodiment described in connection with FIG. 10, the bonding of a Drahtes mentioned, including an additional layer of aluminum, but no adhesive layer of palladium is. In the further embodiments described in DE-OS 19 27 646, which have an adhesive layer made of palladium, nothing is said about the application of solder or bond connections. Rather, it is stated in DE-OS 19 27 646 that a palladium adhesive layer that is thinner than 100 nm, is unstable. In addition, DE-OS 19 27 646 is alloying the adhesive layer in the window is not provided. Finally, DE-OS 19 27 646 remains open, like that Reinforcement layer is applied. In the case of a contact reinforced with gold or silver to 1 to 100 μm a thick palladium layer causes poor electrical and thermal conductivity.

From DE-AS 10 00 533 a method for contacting a semiconductor body is also known. First a palladium layer of a few aluminum layers is formed by ion exchange from an etching solution This palladium layer must, however, according to column 3, lines 5 to 31 of DE-AS 10 00 533 either be reinforced with palladium or with some other material, while solidifying the first Palladium layer applied from the Ätdösung omitted can be.

From US-PS 33 62 851 is a method for production of a connection contact, known from dcTi, is provided with a nickel layer with a thin gold layer

ίο will. However, it has been shown that when applying from lead solder to such a contact, the gold layer from the lead solder completely during the soldering process is dissolved without improving the adhesion between the nickel and the lead solder. A Another disadvantage of using a gold plating is that the remains through the ingested Gold has a greater tendency to form coarse grains, so that with frequent temperature changes it even prematurely fatigued The deficiencies resulting from the application of a gold coating can also be remedied when using do not remove fluxes.

From DE-AS 11 96 793 a method for contacting semiconductor bodies for semiconductor components is known, in which a very thin tin layer is applied to a thin nickel layer. The thin nickel layer is thicker than the very thin tin layer. The very thin tin layer, in turn, is thicker than 1 μm.
The present invention is based on the object of specifying a method which enables a directly solderable or bondable connection contact with a good electrical and thermal conductivity wedge in a window of an insulation layer on a semiconductor body to be made true to geometry without any adjustment work.

This object is achieved according to the invention with a method according to claim 1 or with a method according to claim 2.
The invention makes it possible in an advantageous manner.

the adhesive layer or the contact pad and the metallic Manufacture of reinforcement true to geometry without manual adjustment work. The contact area corresponds to exactly the desired dimensions. An undercut that is present in the etching process to produce the contact patch does not occur. The simple reinforcement of the adhesive layer ensures good solderability or a good contactability of the adhesive layer. Reinforcement of the adhesive layer with a highly conductive metal such as Gold or silver have other advantages. the

such good electrical conductivity and heat dissipation are guaranteed. Good contactability is guaranteed because palladium or nickel can only be applied thinly (about 0.1 μm or 03 μm). On this However, thermocompression cannot be carried out with thin layers alone. The solderability is there improved on layers that are reinforced to 5 to 10 μπι a Contact wire can be soldered better. Highly sensitive semiconductor components become less sensitive when a ductile metal to reinforce the adhesive layer

so is used.

The inventive method is suitable for the production of discrete components, such as for diodes, transistors, but also for the production of integrated circuits.

By alloying the palladium layer or the For example, the nickel layer in the window is thermocompression possible without the need for an additional photoresist technology step

3 4

An embodiment of the present invention of the surface of the adhesive metal cause what a Haf is described on the basis of the figures. They show a reduction in performance of the subsequent metal reinforcement

F i g. 1 and 2 an exemplary embodiment! can result in the invention.

according to the method for producing a contact The semiconductor body 1 or the

on one cm semiconductor body. 5 multiple components resounding semiconductor crystal

In the figures, corresponding parts with washers are sucked in on their back cables and a clcktriden provided with the same reference numerals. Shear contact formed After switching on the power

In an η-doped semiconductor body 1 there is a p-domes and a horizontal placement on a deflated Zone 2 provided. The eiperl and zone 2 has a pn junction 3. Remaining adhesive layer 10 which forms the zone to a contact patch 2 and the semiconductor body 1 form a semiconductor structure with silver or gold galvanically to a thickness of 1 element On a semi-conductor crystal disk, up to 100 μm can be reinforced Such semiconductor components provided bringing the assembly into an electrolyte is very much be. The surface of the semiconductor body 1 is complex and does not provide any reproducible results Silica layer 4 covers the silicon dioxide 15 wax rates. In this way the metal reinforcement layer is created 4 has a window 6 to zone 2. The kung 11 (Fig. 2). As a material for metal reinforcement Window 6 can be produced with the known photographic technology. It is gold or silver or some other electroplated base will. The zone 2 can be suitable by diffusion of res metal. The metal reinforcement 11 can p-doping material, such as boron, by also growing with the help of direct current, if the window 6 produced in the silicon dioxide top layer 4 will not interfere with growths. Otherwise, however, can after the. The silicon dioxide layer 4 and part of the window of the German DE-OB 2041 035 already mentioned 6 are provided with a passivation layer 7. will drive.

For example, silicon nitride is used as the passivation layer 7 after the required contact height has been reached

trid suitable The passivation layer 7, for its part, is rinsed and dried as is known a window 8 that is slightly smaller than the 25th way. Ritz tracks were originally intended. Window 6. Window 8 also leads to zone Z. On which the scratch tracks isolated for reinforcement are placed Passivation layer 7 and then exposed again through the window 8 by etching The part of zone 2 that comes to the surface becomes completely. Instead of an adhesive layer of palladium, it is also possible

An adhesive layer of nickel can be used flatly as the adhesive metal palladium in one layer thickness. nickel vapor-deposited from 50 to 100 nm Order is in the fig. 1 shown alternating current impulses (compare the already mentioned

The adhesive metal, which is a Palla DE-OS 20 41 035), is then deposited.

Forms medium layer 10, alloyed in the window 8 and of

the passivation layer 7 peeled off

bulls required. When alloying, the Palladian 35
surface changed A chemical treatment
however, it makes it possible to ensure that a metal reinforcement that is still to be applied is securely adhered

Contains -a semi-conductor crystal disc scoring tracks
for separating the individual semiconductor components, see above 40
the scoring tracks must be insulated from the electrical current in some way before the adhesive layer 10 is applied. This is for example
possible through the following procedures:

a) Through thermal oxidation, in which only the windows are opened for diffusion.

b) By anodic oxidation according to the in
DE-OS 20 41 035 proposed method. Then the windows are opened with the help of the usual 50
chen photoresist technology open.

c) By an oxidation and subsequent opening
the window with the help of the photoresist technique.

d) By a photoresist technique after manufacture
the cleared contact patch. 55

c) By passivation layers or by nitride layers.
0 By coating with commercially available paints.

These procedural steps are necessary because one- 60
scits the adhesive metal palladium cannot be safely removed from the scribing lines (compare DE-OS
20 41 035) and on the other hand when reinforcing with
Direct current in the first time of amplification creates a shunt across the scoring track. When reinforcing 55
with alternating current, the adhesive metal is mostly off
the Rii / Bahn removed. Again, this would be a
grolic hydrogen evolution and a change

Claims (2)

Patent claims: 1. Method for contacting semiconductor components with at least one pn junction, in which on a semiconductor body (1) at least a window (6, 8) through an insulation layer (4) and / or a passivation layer (7) to the semiconductor body is introduced, in which the entire surface of the insulation layer (4) and / or the Passivation layer (7) and in the window an adhesive layer (10) made of palladium and vapor-deposited on the Insulation layer and / or passivation layer is peeled off and in which finally the adhesive layer (i 0) reinforced with a gold or silver layer (11) is, characterized in that the vapor deposition of the palladium in one layer thickness from 50 to 100 nm, the palladium layer is alloyed in the window before peeling off and that the effect of the palladium layer is galvanic aufl to 100 μπι takes place 2. Method for contacting semiconductor components with at least one pn junction, in which a semiconductor body (1) has at least one window (6, 8) through an insulation layer (4) and / or a passivation layer (7) is introduced into the semiconductor body, bsi the one in the window Adhesive layer is applied and in which finally the adhesive layer with a gold or silver layer is reinforced, characterized in that the adhesive layer is nickel in a layer thickness of 50 Electrically deposited up to 100 nm or galvanically with direct current or alternating current pulses It becomes clear that the nickel layer is wrong. It is alloyed and that the reinforcement of the nickel layer takes place galvanically to t up to 100 μm.