SEMICONDUCTOR DEVICES COMPRISING METALLIZATIONS COMPOSED OF POROUS COPPER AND ASSOCIATED PRODUCTION METHODS
20190221533 ยท 2019-07-18
Assignee
Inventors
- Horst Theuss (Wenzenbach, DE)
- Rudolf Berger (Regensburg, DE)
- Walter HARTNER (Bad Abbach-Peissing, DE)
- Veronika Huber (Bad Abbach, DE)
- Werner Robl (Regensburg, DE)
Cpc classification
H01L2224/73204
ELECTRICITY
H01L2224/0401
ELECTRICITY
H01L2224/13006
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2224/131
ELECTRICITY
H01L2224/73204
ELECTRICITY
H01L2224/13023
ELECTRICITY
H01L2224/0231
ELECTRICITY
H01L2224/03848
ELECTRICITY
H01L2224/05567
ELECTRICITY
H01L2224/32225
ELECTRICITY
H01L21/486
ELECTRICITY
H01L23/49816
ELECTRICITY
H01L2224/131
ELECTRICITY
H01L2224/2919
ELECTRICITY
H01L2224/05008
ELECTRICITY
H01L2224/32225
ELECTRICITY
H01L2224/2919
ELECTRICITY
H01L2924/00
ELECTRICITY
H01L2224/13007
ELECTRICITY
H01L2224/16227
ELECTRICITY
H01L2924/00
ELECTRICITY
H01L2224/16237
ELECTRICITY
H01L23/49827
ELECTRICITY
H01L2224/13024
ELECTRICITY
H01L2924/00014
ELECTRICITY
H01L2224/11848
ELECTRICITY
H01L2224/81191
ELECTRICITY
H01L2224/16225
ELECTRICITY
H01L2924/00014
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2224/16225
ELECTRICITY
H01L2224/13022
ELECTRICITY
H01L2224/03848
ELECTRICITY
H01L2224/05569
ELECTRICITY
International classification
H01L23/498
ELECTRICITY
Abstract
A semiconductor device includes a semiconductor chip, an electrical connection element for electrically connecting the semiconductor device to a carrier, and a metallization adjoining the electrical connection element, the metallization contains porous nanocrystalline copper that contains portions of organic acids.
Claims
1. A semiconductor device, comprising: a semiconductor chip; an electrical connection element that electrically connects the semiconductor device to a carrier; and a metallization adjoining the electrical connection element, wherein the metallization contains porous nanocrystalline copper and wherein the porous nanocrystalline copper contains portions of organic acids.
2. The semiconductor device as claimed in claim 1, wherein the porosity of the porous nanocrystalline copper lies in a range of 5% to 20%.
3. The semiconductor device as claimed in claim 1, wherein a mean pore diameter of the porous nanocrystalline copper is less than 1 m.
4. The semiconductor device as claimed in claim 1, wherein the metallization has a closed-porous region extending at a surface of the metallization.
5. The semiconductor device as claimed in claim 1, wherein the metallization is part of a contact pad of the semiconductor chip and the electrical connection element is arranged on the contact pad.
6. The semiconductor device as claimed in claim 1, wherein the metallization is part of an underbump metallization arranged between a contact pad of the semiconductor chip and the electrical connection element.
7. The semiconductor device as claimed in claim 1, wherein the metallization is part of a copper pillar arranged on the semiconductor chip, the copper pillar being arranged between a contact pad of the semiconductor chip and the electrical connection element.
8. The semiconductor device as claimed in claim 1, wherein the metallization is part of a conductor track of a redistribution layer arranged on the semiconductor chip, wherein the redistribution layer is electrically connected to the electrical connection element.
9. The semiconductor device as claimed in claim 1, wherein the carrier has a first main surface and a second main surface situated opposite the first main surface, wherein the semiconductor chip is arranged on the first main surface of the carrier and the electrical connection element is arranged on the second main surface of the carrier.
10. The semiconductor device as claimed in claim 9, wherein the metallization is part of a conductor track of a redistribution layer within the carrier, wherein the redistribution layer is electrically connected to the electrical connection element.
11. The semiconductor device as claimed in claim 9, wherein the metallization is part of a plurality of metallization planes of a redistribution layer within the carrier.
12. The semiconductor device as claimed in claim 9, wherein the metallization is part of a conductor track on one of the first main surface or the second main surface of the carrier, wherein the conductor track is electrically connected to the electrical connection element.
13. The semiconductor device as claimed in claim 9, wherein the metallization is part of a via connection within the carrier.
14. A method for producing a metallization in a semiconductor device, the method comprising: depositing copper by a electrochemical deposition; and applying a heat treatment to the deposited copper, as a result of which a metallization composed of porous nanocrystalline copper is formed.
15. The method as claimed in claim 14, wherein the electrochemical deposition uses an electrolyte comprised of copper sulfate, ammonium sulfate, and citric acid.
16. The method as claimed in claim 14, wherein the electrochemical deposition uses an electrolyte having a pH of 1.8 to 2.5.
17. The method as claimed in claim 14, wherein a current density used for the electrochemical deposition lies in a range from 0.5 A/dm.sup.2 to 6 A/dm.sup.2.
18. A semiconductor device comprising: a circuit board; a semiconductor component arranged on the circuit board; an electrical connection element, wherein the electrical connection element is electrically connected to the circuit board; and a metallization of the circuit board adjoining the electrical connection element, wherein the metallization contains porous nanocrystalline copper and wherein the porous nanocrystalline copper contains portions of organic acids.
19. The semiconductor device as claimed in claim 18, wherein the metallization is part of a conductor track of a redistribution layer within the circuit board or part of a via connection of the redistribution layer within the circuit board, wherein the redistribution layer is electrically connected to the electrical connection element.
20. A method for producing an electrical connection between a semiconductor device and a carrier, the method comprising: depositing copper by a electrochemical deposition; applying a heat treatment to the deposited copper, as a result of which a metallization composed of porous nanocrystalline copper is formed; and electrically connecting the semiconductor device to the carrier by way of an electrical connection element, wherein the metallization composed of the porous nanocrystalline copper directly adjoins the electrical connection element.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings serve to deepen the understanding of aspects of the present disclosure. The drawings illustrate embodiments and together with the description serve to elucidate the principles of these aspects. The elements of the drawings need not necessarily be true to scale relative to one another. Identical reference signs designate corresponding similar parts.
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DETAILED DESCRIPTION
[0040] In the following detailed description, reference is made to the accompanying drawings, which show for illustration purposes specific aspects and embodiments in which the disclosure can be implemented in practice. In this context, direction terms such as, for example, at the top, at the bottom, at the front, at the back, etc. can be used with respect to the orientation of the figures described. Since the components of the embodiments described can be positioned in different orientations, the direction terms can be used for illustration purposes and are not restrictive in any way whatsoever. Other aspects can be used and structural or logical changes can be made, without departing from the concept of the present disclosure. That is to say that the following detailed description should not be interpreted in a restrictive sense.
[0041]
[0042] The semiconductor device 100 contains a semiconductor chip 2 and an electrical connection element 4 composed e.g. of solder material for electrically connecting the semiconductor device 100 to a carrier (not illustrated). The entire semiconductor chip 2 is not illustrated in the example in
[0043] The semiconductor device 100 can be soldered onto a carrier or a circuit board (not illustrated) for example by means of the connection element 4 composed of solder material. During operation, in the event of temperature fluctuations, on account of different coefficients of thermal expansion of the components (e.g. of the semiconductor chip 2 and of the circuit board), mechanical stresses can then occur which can result in cracks of the electrical connection element 4 or else of the metallization 6, as is evident from corresponding TCoB results. The metallization 6 can be for example a contact pad of the semiconductor chip 2, said contact pad being produced from standard copper in conventional semiconductor devices. In comparison with such a standard copper, however, the nanocrystalline porous copper used in accordance with the disclosure can build up far less mechanical stress 6 with comparable mechanical strain E. As a result, the mechanical stresses mentioned and the instances of cracking associated therewith can be avoided or at least reduced. In each of the examples described herein, such cracking can be avoided or reduced by the use of a metallization comprising porous copper adjoining an electrical connection element.
[0044]
[0045] The semiconductor device 200 contains a circuit board 8 and a semiconductor component 10 arranged on the circuit board 8. The circuit board 8 and the semiconductor component 10 are not completely illustrated in the example in
[0046]
[0047] In S1, copper is deposited electrochemically, wherein the deposited copper can be obtained by a cathode reaction Cu.sup.2++2e.sup.->Cu. Accordingly, a surface on which the copper is deposited during the deposition process can function as cathode. An electrolyte used for the electrochemical deposition can contain copper sulfate (CuSO.sub.4) having an exemplary concentration c(CuSO.sub.4.5H.sub.2O) of approximately 50 g/l to approximately 200 g/l, in particular approximately 100 g/l. Furthermore, the electrolyte can contain ammonium sulfate ((NH.sub.4).sub.2SO.sub.4) having an exemplary concentration c((NH.sub.4).sub.2SO.sub.4) of approximately 25 g/l to approximately 100 g/l, in particular approximately 50 g/l. Furthermore, the electrolyte can contain an organic acid, in particular citric acid (C.sub.6H.sub.8O.sub.7), having an exemplary concentration C(C.sub.6H.sub.8O.sub.7) of approximately 2.5 g/l to approximately 10 g/l, in particular approximately 5 g/l. The growth of copper grains can be suppressed by the citric acid added to the electrolyte. On account of the electrolyte used, the metallization ultimately produced can contain portions of citric acid. The electrolyte used for the electrochemical deposition can have a pH of approximately 1.8 to approximately 2.5. A current density used for the electrochemical deposition can lie in a range of approximately 0.5 A/dm.sup.2 to approximately 6 A/dm.sup.2.
[0048] In S2, the deposited copper is subjected to heat treatment, as a result of which a metallization composed of porous nanocrystalline copper is formed. A temperature-time diagram of an exemplary heat treatment process is shown in
[0049]
[0050] There is arranged on the contact pad 6 an electrical connection element 4 composed of a solder material, which is electrically connected to the contact pad 6 and can thus likewise provide an electrical connection to the internal circuits of the semiconductor chip 2. The solder material of the electrical connection element 4 can be designed, in particular, to electrically and/or mechanically connect the semiconductor device 400 to a carrier or a circuit board (not illustrated). In the example in
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[0053] In the example in
[0054] In the example in
[0055]
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[0057] On its upper and lower main surfaces, the circuit board 8 can have metallizations 18A and 18B, respectively, which are designed to be electrically contacted, for example by the electrical connection element 4 of the semiconductor component 10. Furthermore, the circuit board 8 has an internal redistribution structure, which can be constructed from one or a plurality of conductor tracks 22 and through contacts or via connections 20A, 20B. In the example in
[0058] A plurality of components or metallizations of the circuit board 8 can be produced from porous nanocrystalline copper or at least proportionally contain the latter. In this case, the porous copper can be contained in at least one of the metallizations 18A, 18B, the via connections 20A, 20B, the conductor track 22, the via connection 24. In a further example, in addition, one or more metallizations in the semiconductor component 10 can comprise porous nanocrystalline copper, as described above.
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[0060] The semiconductor chip 2 can be soldered by its electrical connection elements 4A on metallizations 18A on the upper main surface of the carrier 26. In the example in
[0061] In the example in
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[0063] The semiconductor device 1000A contains a semiconductor chip 2 embedded into a mold material 32. Electrical connection elements 4 are arranged on an underside of the semiconductor device 1000A, said electrical connection elements being connected to contact pads of the semiconductor chip 2 by way of a redistribution layer 16.
[0064] The semiconductor device 1000B contains a semiconductor chip 2 with electrical connection elements 4 arranged on contact pads of the semiconductor chip 2.
[0065] The semiconductor device 1000C contains a semiconductor chip 2, on the underside of which are arranged electrical connection elements 4 that are connected to contact pads of the semiconductor chip 2 by way of a redistribution layer 16.
[0066] One or more of the metalizations present in the semiconductor devices 1000A to 1000C can be produced from a porous nanocrystalline copper or at least proportionally contain the latter. By way of example, at least one of the contact pads, underbump metallizations (not illustrated) or metallizations of the redistribution layer 16 can comprise porous copper.
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[0070] Within the meaning of the present description, the terms connected, coupled, electrically connected and/or electrically coupled need not necessarily mean that components must be directly connected or coupled to one another. Intervening components can be present between the connected, coupled, electrically connected or electrically coupled components.
[0071] Furthermore, the word above used for example with reference to a material layer which is formed above a surface of an object or is situated above said surface can be used in the present description in the sense that the material layer is arranged (for example formed, deposited, etc.) directly on, for example in direct contact with, the intended surface. In the present text, the word above used for example with reference to a material layer that is formed or arranged above a surface can also be used in the sense that the material layer is arranged (e.g. formed, deposited, etc.) indirectly on the intended surface, wherein for example one or more additional layers are situated between the intended surface and the material layer.
[0072] Insofar as the terms have, contain, include, having or variants thereof are used either in the detailed description or in the claims, these terms are intended to be inclusive in a manner similar to the term comprise. That is to say that, within the meaning of the present description, the terms have, contain, include, having, comprise and the like are open terms which indicate the presence of stated elements or features but do not exclude further elements or features. The articles a/an or the should be understood to include the plural meaning and also the singular meaning, provided that a different understanding is not clearly obvious from the context.
[0073] Furthermore, the word exemplary in the present text is used in the sense that it serves as an example, an instance or an illustration. One aspect or one design which is described as exemplary in the present text should not necessarily be understood as though it has advantages over other aspects or designs. Rather, the use of the word exemplary is intended to present concepts in a concrete manner. Within the meaning of this application, the term or does not mean an exclusive or, but rather an inclusive or. That is to say that, provided that nothing to the contrary is indicated or the context does not permit a different interpretation, X uses A or B means any of the natural inclusive permutations. That is to say that if X uses A, X uses B or X uses both A and B, then X uses A or B is satisfied in each of the cases mentioned above. Moreover, the articles a/an within the meaning of this application and the accompanying claims can generally be interpreted as one or more, unless it is expressly stated or clearly discernible from the context that only a singular is meant. Furthermore, at least one of A and B or the like generally means A or B or both A and B.
[0074] Devices and methods for producing devices are described in the present text. Observations made in connection with a device described can also apply to a corresponding method, and vice versa. If for example a specific component of a device is described, then a corresponding method for producing the device can contain a process for providing the component in a suitable manner, even if such a process is not explicitly described or illustrated in the figures. Moreover, the features of the various exemplary aspects as described in the present text can be combined with one another, unless expressly noted otherwise.
[0075] Although the disclosure has been shown and described with reference to one or more implementations, equivalent alterations and modifications which are based at least partly on the reading and understanding of this description and the accompanying drawings will be apparent to the person skilled in the art. The disclosure includes all such modifications and alterations and is restricted solely by the concept of the following claims. Especially with regard to the various functions performed by the above-described components (for example elements, resources, etc.), the intention is that, unless indicated otherwise, the terms used for describing such components correspond to any components which perform the specified function of the described component (which is functionally equivalent, for example), even if it is not structurally equivalent to the disclosed structure which performs the function of the exemplary implementations of the disclosure that are illustrated herein. Furthermore, even if a specific feature of the disclosure has been disclosed with reference to only one of various implementations, such a feature can be combined with one or more other features of the other implementations in a manner such as is desired and is advantageous for a given or specific application.
LIST OF REFERENCE SIGNS
[0076] 2 semiconductor chip [0077] 4 electrical connection element [0078] 6 metallization [0079] 8 carrier/circuit board [0080] 10 semiconductor device [0081] 12 passivation layer [0082] 14 contact pad [0083] 16 redistribution layer [0084] 18 metallization [0085] 20 via connection [0086] 22 conductor track [0087] 24 via connection [0088] 26 carrier [0089] 28 underfill material [0090] 30 circuit board [0091] 32 mold material