DE2352329C3 - Semiconductor component and method for its manufacture - Google Patents

Description

, CO CO

R 'NRN CO' 'CO sehlusselekiruden (25, 28; W, 40), thereby characterized that the assemblies the special structure

CO _x , CO _x
/ Ar, '

/ / ^x CO
N - C

Ar,

CN

Il ο

-CO CO

Ar ₁ ■ - N Ar, N

CO * CO

and the radicals An and Arj are groups derived from benzene, diphenyl ether, naphihaline, diphenyl sulfone and>, ο di (phenoxyphenyl) sulfone and the radicals Ar ₂ and Ar.) are radicals derived from benzene, diphenyl ether and benzophenone.

2. Semiconductor component according to claim!, Characterized in that the radicals An and An are derived from diphenyl ether groups, the radical Ar _{2 is} a group derived from benzene and the radical Ar _{4 is} a group derived from benzophenone.

3. Semiconductor component according to claim!, Characterized by a polyimide resin layer (24), obtained by polycondensation of 5 mol% 4,4'-Diaminodiphynyl ether-3-carboxamide, 45 mol% 4,4'-Diaminodiphenylether. 25 mol% pyro mellitic dianhydride and 25 mol% 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride.

4. Semiconductor component according to one of claims 1 to 3, characterized by one between the SiOr layer (23) and the polyimide resin layer (24) inserted primer (36) made of an organic Material such as an aminosilane compound or an Epoxysila η compound.

5. Semiconductor component according to claim 4, characterized in that the primer (36) also is applied between the connection electrodes (25, 28; 39, 40) and the polyimide resin layer (24).

6. Semiconductor component according to one of claims 1 to 5, characterized by a thickness of the Polyimide resin layer (24) from 2 to 15 μm.

7. A method for producing a semiconductor component according to any one of claims I to 6, at a polyimide resin solution is applied to the SiOr layer, the device for Applying the solution and rotating the semiconductor body relative to each other, in which the solution through Heating is cured, in which the polyimide resin layer and the SiOr layer are etched, so that openings for the connection electrodes are formed and in the case of the Elcktrodenmetall within the Openings is deposited, characterized in that the semiconductor body (20) during application the solution is rotated so that the polyimide resin layer (24) is etched with an oxygen plasma and that the electrode metal is vapor-deposited or sputtered with rotation of the semiconductor body (20) will.

8. A method for producing a semiconductor component according to claim 5, in which a polyimide _{resin solution is applied to the SiO 2} layer and cured by heating, in which the polyimide _{resin layer formed is etched, namely in the SiO 2} layer openings for the connection electrodes and is deposited in the electrode metal within the openings, characterized in that openings for the connection electrodes (39, 40) are first formed in the SiO ₂ layer (23), and then the electrode metal is applied to the SiO 2 layer (23) and is etched in such a way that electrodes (39, 40) protruding over the surface of the SiOj layer (23) with a trapezoidal cross-section are formed, so that the surface of the SiO ₂ layer (23) and the electrodes (39, 40) are then primed and coated the primer (36), the polyimide resin layer (24) is applied and that the polyimide resin layer (24) is then evenly removed with an oxygen plasma to such an extent that until the upper horizontal surface of the electrodes (39,40) is exposed in the plane of the surface of the polyimide resin layer (24).

The invention relates to a semiconductor device with a lying on the surface of the semiconductor body and a SiO ₂ layer overlying the SiO ₂ layer protective layer of a polyimide resin having

'25 52

Ι $; ΐϋμΐΊ! |> |! Ι. '! 1 of the general structure

(O (O

IV NRN

co co

in the ilie RcMl · R 'mid R; ιι <miaIiseho Resie are, mill mil through the SiOj layer and through clic Polyimidhar / I see the hu Γ clic surface of the semiconductor body In ι! Penetrating connection electrodes.

The Polymiidhar / Sehicht Jieni both the school / The semiconductor assembly element is also fully automated Soldering of the connection pins. Hey this one The first process is the coated liaiielment / in Production of the solder balls in a bath with the melted and immersed in solder. Di '·!' Olyimiclhiiiv layer da: I am not involved either in this roping or in the later one Melting of the oil pearls neither in terms of them chemical change in terms of their mechanical, nor in terms of their electrical characteristics.

Kin semiconductor component of the type mentioned is known from DT-AS 17 64 977. The polyimide resin layer is not attacked even if it is very thin in a bail made of molten lead-tin solder, i.e. with a soldering temperature of around 180 to 200 ° C, and remains firmly on the Si (').> Layer. In the use of solders mil higher melting temperature, in particular at solders mii a melting temperature of above about .350 "C, however, the electrical characteristics are the Polyimidhar" hieht of bckannien I lalbleiierbauelementes deteriorated by GrölJenordnungen. In the case of the component, this leads to a noticeable increase in the leakage current and, in the case of transistors, for example, to a noticeable reduction in the gain factor. Also is

Is the dielectric I> r ^: \ hschlaiilcsligkcil the in the known semiconductor component veiλ \ cn.lcieii Polyiniidhar / Schichl already at room temperature with values / wipe about 210 to JOO V / μιιι flour all / u large.

Liner automating the manufacture of the Dr-ihtaii The drive to miniaturize is also an issue Exercises in the field of semiconductor construction opposite. The in common semiconductor elements leu for making the wire connections /; ir available standing electrode surfaces have a diameter in the range of about 60 to 100 μm In view of the reduction in surface dimensions that is sought for technical and economic reasons of semiconductor components, an enlargement of the connection electrode surface could be achieved thereby achieved weiden that this window over the connection on the outer insulator layer of the Semiconductor building genienies is extended beyond. the Common materials for these insulator layers including those known from DT-AS 17 64 977 Polyimide resins, however, have so unfavorable dielectric and / or thermal characteristics that such an enlargement of the connection electrode surface for capacitive reasons prohibits.

In view of this state of the art, there are no eggs The object of the invention is to create a semiconductor component of the type mentioned at the outset, whose Wire connections even at high soldering or welding temperatures with relatively simple mass production equipment can be produced without impairing the electrical characteristics of the component.

To solve this problem, a semiconductor component of the type mentioned is proposed which according to the invention is characterized in that the assemblies have the special structure

CO \ , CO s

/ / N-C

Ar, N-Ar ₁ -N

^ ⁷

-Ar,

C-- N

Il ο χ / CO _x
Ar, N-

have and the radicals Ar; and Arj from benzene. Diphenyl ether, naphthalene, diphenyl sulfone and di (phenoxyphenyl) sulfone derived groups and the radicals Ai "2 and Ar.i from benzene, diphenyl ether and Are benzophenone derived residues.

This semiconductor component can also be exposed to soldering temperatures in the range from 300 to 450 ^° C., sometimes also higher temperatures, without its electrical or the dielectric properties of its polyimide resin layer being impaired.

The invention is described below with reference to exemplary embodiments in conjunction with the drawings explained in more detail. It shows ho

Fig. I a common planar transistor,

Fig. 2 to 2b an embodiment of the invention and its production,

F i g. 3 shows a second embodiment of the invention

FIGS. 4 to 4b show a third exemplary embodiment of FIG. 6s Invention and its creation,

5 to 5c a fourth embodiment of the invention and its manufacture and 6 shows the production yield in a graph in the manufacture of the seal as a function of the thickness of the polyimide resin layer.

For a better understanding of the invention, a common planar transistor is shown in FIG a collector substrate 1, a base 2, an emitter .3 and an insulator layer 4 shown. In connection windows, which are opened in the insulator layer 4, a base electrode 5 and an emitter electrode 6 are arranged, on which the base connection wire 7 and the emitter connection wire 8 are fastened. The diameter of electrodes 5 and 6 is, as stated above, usually in the range from 60 to 100 μm. at Silicon semiconductor components, the insulator layer is usually a SiOj layer, which is made of technical and for economic reasons, it is not significantly thicker than about I μm. An enlargement of the too Connection purposes available surface of the electrodes 5 and 6 over the diameter of the A window on the surface of the insulator layer causes interference capacitances to the base and to the emitter.

The same effect already occurs with the one shown in FIG. 1 solder distribution shown during connection production. The resulting disadvantages are due the invention resolved without relying on a relatively large terminal electrode surface, the basis of mass production is to be dispensed with.

As a first embodiment of the invention, a planar transistor is shown in FIG. An n-Si substrate serves as a collector. A p-conducting base 21 and an η-conducting emitter 22 are formed in the substrate using planar technology. The surface of the substrate 20 is covered with an SiO ₂ layer 23 and this with a polyimide resin layer 24. The polyimide resin layer 24 is 5 μm thick. A base connection electrode 25 extends through both layers to the base region of the transistor through an opening in the polyimide resin layer 24 and the SiO _{2 layer 23.} The base electrode 25 consists of two metal layers. The first metal layer lies on the surface of the transistor base and establishes the connection between this and the second metal layer 27, which partially extends as far as the surface of the polyimide resin layer 24. In the same way, an emitter electrode 28 also consists of a first metal layer 29 and a second metal layer 30. A base connection beam 31 and an emitter connection wire 32 are attached to the surfaces of the electrodes.

The transistor shown in Fig. 2 is fabricated as follows. The base region 21 is formed by diffusing boron into the n-Si substrate 20. The emitter 22 is produced by diffusing phosphorus in the boron-boron-type area. Subsequently, the SiO ₂ layer 23 is applied with the base connection window and the terminal connection window. The aluminum layers 26 and 29 are introduced into the window as the first metal layer for the connection electrodes (FIG. 2a). The surfaces of the SiO layer 23 and the aluminum layers 26 and 29 are then coated with a 5 μm thick polyimide resin layer 24. A metal mask 3.3 is applied to the polyimide resin layer 24, in which fenders 34 and 35 are opened at the points above the aluminum layers 26 and 29 (FIG. 2b). The polyimide resin layer 24 is then removed through these windows 34 and 35 so that the surfaces of the aluminum layers 26 and 29 are exposed. After the mask 33 has been removed, the second Elcktrodcnmctall 27 or 28 in the in I'ig. 2 training shown with the production of an electric Koniaklcs to the light

Aluminum layers applied. The connection electrodes 25 and 28 produced in this way also extend aul the surface of the polyimide resin layer 24 and thus provide a sufficiently large surface for welding or soldering the connecting wires 31 and 32 zui available. Because of the excellent and aucr dielectric properties of the polyimide layer 2 which are not deteriorated under the soldering temperature, the ir F i g. 2 semiconductor component shown no stray capacitances between the connection electrodes and deir Semiconductors on.

The polyimide resin layer 24 is first applied in the form of a prepolymer solution. Such A prepolymer solution is obtained, for example, by precondensing a solution composed as follows Get a mixture:

Non-volatile components:

4,4'-diaminodiphenyl

ether-3-carboxamide 5 mol%

4,4'-diaminodiphenyl ether 45 mol%

Pyromellitic acid dianhydride 25 mol% S.S '^' - Benzophenone tetracarbon

acid dianhydride 25 mol%

Solvent components:

N-methyl-2-pyrrolidone 50% by weight

Ν, Ν-dimethylacetoamide 50% by weight

concentration

of non-volatile substances 20% by weight

Solution viscosity about 300 cP

If this prepolymer solution is centrifuged at a rotor speed of 5000min- ' applied, a polyimide resin layer with a thickness of 1 μm is obtained. This thickness can go through a change in the viscosity of the prepolymer solution, due to a change in the concentration of the non-volatile Components, by changing the speed of the rotor thrch or a combination of these measures can be set. According to the requirements of the individual case, polyimide resin layers in the order of magnitude can thus be used from I to 10 μm can be produced. The thickness of the polyimide resin layer is preferably about 5 μm.

After all of the above-mentioned items have been polymerized Pre-polymer solution, a polyimide resin is formed on the SKVSchichl, the assemblies of the following Structure has:

co - \ co

N I I] N

C \ (O

O "." ■■ ('N

Il ο

\ / N. COv

co ^ c ^s coil

(ID

The opening of the isolators in the oil-in-liquid layer is preferably possible with the use of an acidic shock plasma. When using a 0.7 kW plasma with an ice-cream parlial thickness of 0.8 uibar and a volume current of tl / inin, a 5 μm thick polyimulus is obtained. Layer completely abated after 10 minutes / l. Dk ¹ Si ¹ AlziliiiiiT can by changing the SauersloUvolunieiiMroins, the SaiiersloHpartiaklnieks I loehfrci | ucnzli'istung

and h /, w, or the
IMIIgL-SIi ¹ IIi graze.

Dii the plasma etching using a Mclallmaske 1) takes place, make sure that the Mask is either significantly thinner than the lowermost Mekirodcnuielallcliiehlen 26 and 29 or made of a material that can be removed by a solvent that removes the elec-

Dcnmetallschichten 26 and 29 does not attack. In this one The exemplary embodiment described consists of both the electrode layers 26 and 29 and the mask 33 made of aluminium. The mask is 0.4 μm thick, while the Electrode metal layers 26 and 29 are 1 μm thick. Under these conditions, the mask 33 are completely detached and at the same time the electrode metal layers 26 and 29 remain in sufficient Thick standing.

It is not necessary that the two metal layers of one and the same electrode be made of different ones Metals. In the exemplary embodiment described here, the second electrode metal layers also exist 27 and 30 made of aluminum. They are made by vapor deposition of an aluminum layer on the surface of the polyimide resin layer 24 and into its opened terminal electrode window and then selective etching of the vapor deposition layer produced. To ensure that the relatively deep window in the Polyimide layer 24 can also be evenly and completely filled out during the vapor deposition of the aluminum, the semiconductor substrate 20 is preferably rotated during the vapor deposition.

Another embodiment of the invention is shown in FIG. 3 shown. This transistor corresponds essentially to that in FIG. 2 and differs therefrom in that _{an adhesion promoter layer 36 is inserted between the SiO 2} layer 23 and the polyimide resin layer 24. The adhesion promoter contains alkoxysilane groups to mediate a chemical bond to inorganic materials as well as amino groups and / or epoxy groups to mediate chemical bonds to the polyimide resin layer.

Commercially available aminosilanes in the form of solutions with concentrations of 0.05 to 20% by weight can serve as the material for the adhesive layer 36. Preferably, a 1% strength by weight isopropanol solution of N- / I- (aminoethyl) -) '- aminopropyl-methyldimyloxy-siian is used to produce the adhesion promoter layer 3b. The applied solutions are dried ^{at 100 °} C. for about 30 minutes in a customary manner.

Diis in fig. 4 shown embodiment of the Invention differs from that in FIGS. 2 and 3 essentially in that the liasisclekt'ode 25 and the emitter electrode 28 consist of only one metal layer each.

Ik-i the manufacture of the structure shown in Fig. 4, after the Trockiien · I lallvermitllerschicht 36, the prepolymer of the above-described PoIyiinidliaiv.es applied at '00 "C and then dried th hei H) O C ¹ cured. The Polyimklhaiz Layer is H j in the tlu-k. Aul this polyimide layer 24 is then formed an aluminum line with windows 14 and 53 over the base glass or the air area (Ii): - Ia). Plasma etching is then carried out through the Maskcuöl'fnungeii M and .15 windows in the PolyiniidhaiY.schiehi open up to the surface of the SiO .. layer. Through the l'lasmaillzeii cm l'ensler in the aminosilari I liiftvcrniittlei ■ layer Jd is opened, t inter The window opened in this way in the nitrile resin layer is then also opened in the exposed SiO layer using common etching agents, for example a fluorous acidic amine in a liquid solution fnet. In this way, finally, ■ .Im '. ¹ Ii the entire Schichistniktiir liiiidiirgreil'ende connection contact window 37 created for the base and 38 for the emitter. After the aluminum mask 33 has been detached, an aluminum layer is applied by cathode sputtering, which also completely fills the windows while making electrical contact with the base and the emitter. The aluminum layer is then selectively etched to form the connection electrode surfaces. The connecting wires 31 and 32 are then welded by hot pressing or ultrasonic welding

ίο welded on. Here, even the relatively thick polyimide resin layer maintains a relatively high welding temperatures ranging from 45O ⁰ C without degradation of its dielectric characteristics stand. Neither cracking nor a decrease in breakdown voltage occurs.

In FIG. Finally, FIG. 5 is a further exemplary embodiment of the invention, also using the example of one Planar transistor shown. The base electrode 25 and the emitter electrode 28 each consist of an im Cross-section of essentially trapezoidal metal web 39 »40, the electrical contact to the Base or to the emitter produces and its upper end face in the surface of the polyimide resin layer 24 is exposed and there is electrically conductively connected to connecting plates 41, 42. The adhesion promoter layer is not only inserted between the SKV layer 23 and the polyimide resin layer 24, but encloses it also the side surfaces of the electrode webs which are in contact with the polyimide resin layer 39.40.

In the production of this rough element, the procedure is that the substrate surface is first is covered with a SiOa layer, in which then windows to the base and to the emitter are opened. To this

The structure is a 5 μm thick aluminum layer dejected. By selective etching, the Elcktrodenstege 39 and 40 shown in Figure 5a on the Base and the emitter formed. The structure obtained is on its entire surface with a Aminosilane adhesion promoter layer 36 coated. This layer is then applied in the manner described while rotating the semiconductor structure, a finally 6 μm thick polyimide resin layer is applied (FIG. 5b). By etching with an oxygen plasma, the

_4S , the structure obtained is evenly removed until the upper end faces of the electrode pieces 39, 40 are exposed in the surface of the polyimide resin layer 24. The structure obtained is finally vapor-deposited with aluminum and the connection plates are formed

., ο 41, 42 selectively etched. After attaching the connecting wires .11 and 32 become the structure shown in FIG receive.

In order to ensure the best possible surface formation, the polyimide resin Schidit 24 is

, s trainsweisc so thick that they with the Electruile bars coated with adhesion promoters well covers.

The polyimide chloride 24 is preferably made from a polymer of the general chemical formula

, "I. in the Λιί a Diplieiiylätliergruppe, Ar. · An ilciizolnng, Ar ₁ a Diphenylätlicrgnippe and Ai. ₍ mean a licn / opliciiongruppc.

The polyamide film 24 can stow with a Oxygen plasma also chemically etched selectively

< _1S will be. After the prepolymer solution has been applied and the wet coating has been heat-treated for one hour at IbO ¹¹ C, the solvent in the layer is largely evaporated without this

Polyimide is already fully cured. In this not yet condensed state, the layer can be etched well with 40 to 80% by weight hydrazine solution. By a subsequent heat treatment of one hour at 200 "C and then 30O ⁰ C the polyimide is fully cured and has the same properties as the durchgehä'rtete in a process and by the oxygen plasma etched polyimide resin layer.

As an electrode material in connection with the polyimide resin layer, aluminum can also be used other materials, especially titanium, molybdenum, gold, silver, copper, chromium and platinum as well Alloys of these metals can be used.

The polyimide resin layer preferably has a thickness of 2 to 15 μm. For the sake of mechanical Strength when making the wire connections, the layer thickness should be at least 2 μίτι and for reasons of Etchability not be more than 15 μm. For economic reasons, a thickness is used for the Polyimide resin layer in the range from 3 to ΙΟμηι preferably complied with. The reason for this is the fig. 6 can be found. In automatic production the production yield of the wire connection stage with a polyimide resin layer of 2 μητι is only 50%, while it is already practically 100% with a layer thickness of 3 μm.

Instead of the aminosilanes described above as adhesion promoters, epoxysilanes can also be used are, preferably ß- (3,4-epoxycyclo-

hexyl) ethyl trimethoxysilane and γ-glycidoxypropyl trimethoxysilane.

As proof of improved temperature behavior the electrical characteristics of semiconductor components with the polyimide resin layer according to the invention two series of planar transistors of the structure shown in FIG. 2 were used in comparative experiments manufactured. Test objects of a series A have a polyimide layer with assemblies of the formula 11, while specimens of a series B contain a polyimide resin layer with assemblies of the following formula:

The current amplification factors of the test items are measured, i.e. the ratio of the collector current to the base current. The test specimens produced identically in the manner described are first at room temperature, then after a heat treatment of 60 min at 350 ° C, then after a subsequent heat treatment of IC min at 450 ° C and finally after a subsequent heat treatment of 3 min measured at 500 ^{° C.} The corresponding values for specimens A according to the invention are 58%, 58%, 60% and 59%. The comparison values for test items B are 57%, 57%, 18% and 8%. The results show that the semiconductor component of the invention can, if necessary, also be wired at 500 ° C., while the wiring temperature of the comparison component is as high as? 300 to 350 ° C should be used.

Moreover, polyimide resin layers were at the two mentioned μιτ in a layer thickness of 1 per the breakdown voltages at room temperature measured after the samples were heat treated respectively for 5 h at 250, 350 400 and 450 ⁰ C. The impact strengths for the polyimide resin layers are used in the semiconductor component of the invention! in units of V / μm are 420, 425, 410, 390 and 340. The same values for the comparative samples are 260, 280, 285, 200 and 50.

For this -I Matt drawings

Claims (1)

Patent claims: I. Semiconductor component with a surface on a egg of the semiconductor body lying SiO .. layer and a protective layer overlying the SiOr layer in which the radicals R 'and R are aromatic radicals and with through the SiO _.- layer (23) and through the Polyimidhiirz-layer (24) on the surface of the I lalbleiterkörpers (20) penetrating layer from a polyimide / with assemblies of the general structure