DE102017104923A1 - Connection for a semiconductor chip - Google Patents

Abstract

Electrical component (9) comprising at least one base component (8) with at least one semiconductor chip (2), wherein the semiconductor chip (2) is connected to the base component (8), wherein a connection (1) between respective contact surfaces (3) of the semiconductor chip ( 2) and the base member (8) via a plurality of nanowires (4) is formed.

Description

The invention relates to a connection for a semiconductor chip, in particular with a basic component of an electrical component.

There are a variety of semiconductor chips for a variety of applications known. In many applications, the semiconductor chips are applied to a substrate. In addition, adhesive bonding methods are used regularly. It may, for. B. come to a "floating" of the semiconductor chip. This means that the semiconductor chip remains mobile until the adhesive has cured. This can lead to an inaccurate positioning of the semiconductor chip. Also, a waiting time between sticking of the semiconductor chip and subsequent process steps is necessary. In particular, when forming an electrical connection of the semiconductor chip to other components (i.e., during so-called "bonding"), an insufficiently cured and / or incompletely formed connection can be problematic. Thus, by bonding the semiconductor chip can be moved and / or damaged or the bond connections can be poor or even not formed.

In known electrical devices in which semiconductor chips are used, in particular thermal and / or mechanical loads can be particularly pronounced. These burden not only the semiconductor chip and the substrate, but also the connection between the two. In particular, in devices in which the semiconductor chips are not installed in a central control unit, but are arranged distributed decentralized over individual components of the device, there is so often a break or damage to the connection between the semiconductor chip and the substrate.

The method for forming the connection between the semiconductor chip and the substrate can be expensive (and require, for example, complex machines). The method can also make pronounced demands on the components to be connected (for example with regard to a minimum material thickness). Furthermore, such compounds are often not long term stable (i.e., exhibit undesirable aging phenomena such as corrosion).

A disadvantage that many connections between semiconductor chips and substrate according to the prior art have in common is the lack of thermal stability. Thus, there are applications in which the maximum thermal load of an electrical device is not limited by the individual components (such as semiconductor chip and / or substrate), but by the compounds formed therein. Also, many known solutions have the disadvantage that the connection over a surface is often uneven.

Known semiconductor chips are often formed of silicon. However, silicon has the disadvantage that it is not sufficiently thermally stable for some applications. This means that a temperature that occurs in a given application can damage a silicon chip. As a solution to this problem, it has been proposed to use the thermally stable silicon carbide (SiC). However, silicon carbide has the disadvantage that in the prior art for this material only insufficient connections to a substrate are known. For example, high temperature solders are used. However, these regularly have the disadvantage, in particular due to a particularly high proportion of heavy metals, to be harmful to health.

On this basis, it is an object of the present invention to solve the technical problems described in connection with the prior art or at least reduce. In particular, an electrical component is to be presented, in which a semiconductor chip, in particular one made of silicon carbide, is connected to a base component (such as a substrate), wherein the connection can be easily formed, makes low demands on the components to be connected, long-term is, has a particularly low thermal resistance, is thermally stable and can be uniformly formed over a surface. Furthermore, a manufacturing method for such an electrical component is to be presented.

These objects are achieved with an electrical component according to the features of patent claim 1, with a use of a film according to the features of patent claim 7 and with a method for producing an electrical component according to the features of patent claim 11. Further advantageous embodiments are dependent in each case formulated claims. The features listed individually in the claims can be combined with each other in any technologically meaningful manner and can be supplemented by explanatory facts from the description, with further embodiments of the invention being shown.

According to the invention, an electrical component having at least one base component with at least one semiconductor chip is proposed. The semiconductor chip is connected to the base component, wherein a connection between respective contact surfaces of the semiconductor chip and the base component is formed via a multiplicity of nanowires.

Here, a semiconductor chip is understood to be any material body made of a semiconductor material, on or in which a nano- or microstructure is provided. A nano or microstructure may in particular be a structure with elements of the order of a few nanometers to several micrometers. This structure can in particular represent an integrated electronic circuit. The term of the semiconductor chip is here to be interpreted broadly and in particular not with regard to design features (not specified further than explicitly) restrict. For example, the semiconductor chip may be a processor for a computer, a limited task computer chip, a computer memory, a transistor, or a diode.

The basic component can be any component of the electrical component that has a surface that is set up and intended for receiving and / or mechanically holding a semiconductor chip. This means in particular that the basic component preferably has at least one surface which has a sufficient size and which is sufficiently straight (in particular completely flat). This surface preferably has a contact surface for the semiconductor chip. It is particularly preferred that the base component is a substrate, in particular a ceramic material.

A contact surface is preferably a spatially distinguished region of the respective component (i.e., the semiconductor chip or the base component). For example, a contact surface may be formed as a (partial) surface of the semiconductor chip. Alternatively, it is preferable that the contact surfaces be distinguished by forming the connection. This means that the contact surface initially does not differ from a remaining surface and emerges only by forming the connection in such a way that the contact surface is the surface on which the connection is formed. In this case, the contact surface is delimited mentally (i.e., without spatial distinction) from the remainder of the surface. This applies in particular to the contact surface on the surface of the base component. The base is preferably uniform, i. a contact surface of the base component is only distinguished by the formation of the connection with the semiconductor chip. It is preferable that precisely two pads are involved in the connection (i.e., one contact surface of the semiconductor chip and one contact surface of the base member).

It is particularly preferred for the nanowires to be provided over part of the surface of the base component (in particular over the entire surface of the base component). Only a part of the nanowires thus provided is used to form the connection with the semiconductor chip. This means that the nanowires are provided over a surface of which only parts are used as contact surfaces. These parts of the surface can also be distributed in a structured manner over the surface. For the remaining parts of this area, the nanowires remain unused.

A nanowire is understood to mean any material body that has a wire-like shape and a size in the range of a few nanometers to a few micrometers. A nanowire may e.g. have a circular, oval or polygonal base. In particular, a nanowire may have a hexagonal base. Preferably, all nanowires involved in the connection are formed from the same material. The nanowires may be formed as hollow tubes. Also, the nanowires may be conically shaped.

The nanowires preferably have a length in the range of 100 nm [nanometers] to 100 [microns], in particular in the range of 500 nm to 30 [mu] m. Furthermore, the nanowires preferably have a diameter in the range from 10 nm to 10 .mu.m, in particular in the range from 30 nm to 2 .mu.m. In this case, the term diameter refers to a circular base area, wherein a comparable definition of a diameter is to be used in the case of a deviating base area. It is particularly preferred that all nanowires used have the same length and the same diameter.

The connection is preferably formed by providing the plurality of nanowires between the respective contact surfaces to be connected. This can be done by providing a plurality of the nanowires on one of the contact surfaces involved in the connection. Also, in each case a plurality of the nanowires can be provided on each of the contact surfaces. In both cases, the connection can be formed by touching the contact surfaces.

Due to the size of the nanowires in the nanometer range, the surface area of the interconnect (i.e., the area over which forces such as the van der Waals force act at the atomic level, and over which, in addition, feathering of the nanowires occurs) is particularly large. Due to the large surface area of the compound, thermal conductivity of the compound can be particularly high. This can for example improve the cooling of the electrical component, in particular of the semiconductor chip.

The described connection can furthermore be particularly simple and without tools be formed. It is only necessary to connect the contact surfaces to be connected to each other. A pressure can optionally be exercised, but is not mandatory.

In particular, the connection can be formed instantaneously. Thus, the above-described floating in solutions according to the prior art is avoided. The once applied semiconductor chip is instantaneously fixed in position. In this way, a particularly precise positioning of the semiconductor chip on the base component can be achieved. Waiting time after application of the semiconductor chip (such as to harden an adhesive bond) is not required, which can increase the efficiency of the manufacturing process. In particular, the problems described above can be circumvented when bonding, which occur regularly in solutions according to the state of the art. It is particularly preferred that the semiconductor chip is automatically positioned with a (in particular computer-controlled) gripper.

As a requirement for the components to be connected (i.e., the semiconductor chip and the base member), it should be noted here only that the plurality of nanowires may be provided between the respective pads. However, this is possible with a large number of contact surface materials (in particular also with ceramic materials). Also, the compound described shows no signs of aging. In particular, the compound described is particularly well protected against corrosion. The compound can also be particularly thermally stable. Thermally stable here means that the compound also remains under temperature increase and in particular is not damaged. The reason for the thermal stability is that the compound obtains stability over the large contact surface. This remains unchanged at a temperature change. A particularly thermally stable compound can be formed when the nanowires are formed with thermally stable materials such as gold, silver, and / or copper.

Furthermore, the described compound can be formed uniformly over a surface. Also, a hermetic sealing between the contact surfaces involved in the connection can be achieved via the connection described. Again, this is due to the large surface area of the connection. In particular, such an air inclusion between the semiconductor chip and the surface of the base member can be avoided.

Furthermore, the described compound can dampen vibrations and similar mechanical loads particularly well. This is because the connection is not formed flat between the contact surfaces themselves, but indirectly via the flexible nanowires in between. This forms an intermediate layer between the rigid contact surfaces, which can compensate for mechanical stresses particularly well. The compound is particularly particularly long-term stability, because a breakage of a rigid connection is bypassed. In particular, the length of the nanowires and a (optionally) applied compressive force (i.e., an applied pressure) when the connection is formed may influence the expression of this resilient action of the nanowires.

Preferably, the connection is made non-detachable. This means that the connection can not be resolved under normal circumstances. Only by damaging the components involved in the connection can the connection be destroyed (i.e., under abnormal circumstances).

The nanowires may be formed in any orientation between the contact surfaces involved in the connection. For example, the nanowires may have a different orientation at each of the contact surfaces involved in the connection, so that the nanowires z. B. caught at an angle to each other. It is also possible for a contact surface to be subdivided into a plurality of partial regions, the nanowires being differently oriented in the various partial regions. Thus, a particularly stable connection can be realized, which can withstand shear forces particularly well. Furthermore, it is possible that the nanowires are made differently at the different contact pads involved in the connection, in particular with regard to their length, diameter, material and density (the density of the nanowires indicating how many nanowires are provided per surface). For example, For example, small nanowires of one contact surface can intervene in a structure of large nanowires of the other contact surface.

In a preferred embodiment of the compound, the nanowires are oriented perpendicular to at least one of the contact surfaces involved in the connection.

Preferably, two contact surfaces are involved in the connection, which are oriented parallel to each other. In that case, the nanowires are preferably oriented perpendicular to both contact surfaces. Due to the perpendicular orientation to at least one of the contact surfaces, the connection can be formed over a particularly large surface area (the nanowires). As a result, the connection can be made particularly stable. The advantages described above can be achieved particularly well in this embodiment.

In a further preferred embodiment of the electrical component, an adhesive connection is additionally formed between the contact surfaces involved in the connection.

The adhesive compound may e.g. be formed with an adhesive or a polymeric material. Due to the additional adhesive compound, the mechanical stability of the compound can be particularly strengthened. Preferably, the adhesive compound is formed as an adhesive layer.

In a further preferred embodiment of the electrical component, each contact surface involved in the connection has a multiplicity of nanowires.

The connection is formed in this embodiment by providing a plurality of nanowires on each of the involved pads, and bringing the nanowires into contact by approaching the pads. This means that the connection between the nanowires of the respective contact surfaces is formed. Thereby, a particularly large contact surface of the connection (i.e., the nanowires forming it) can be achieved.

In a further preferred embodiment of the electrical component, the semiconductor chip is formed at least partially with silicon carbide.

The described connection between the semiconductor chip and the base component can in particular also be used for a semiconductor chip according to this embodiment. Thus, the compound described herein enables the use of silicon carbide, which can provide the benefits described above resulting from the use of this material.

This applies in particular in a further preferred embodiment of the electrical component, in which the contact surfaces provided on the base component are at least partially formed with a ceramic material. A further aspect of the invention relates to a use of a film for forming a connection of a semiconductor chip to a base component of an electrical component, wherein the connection between respective contact surfaces of the semiconductor chip and the base component is formed over a plurality of nanowires, wherein within the film a plurality of nanowires is included, and wherein the film between each contact surfaces of the semiconductor chip and the base member is included.

Preferably, the nanowires are formed by growing them in a patterned film. This z. B. galvanic methods are used. By dissolving the film (eg chemically or thermally), the grown nanowires can be dissolved out of the film. However, if one leaves the nanowires in the film, then this film can be used according to the use described here for forming the connection of the semiconductor chip to the base component. By thus using the film, the method for forming the connection can be simplified. In particular, the location of the production of the nanowires and the place of formation of the connection can be separated from each other. The film produced once can be used as known adhesive strips. Also, the film may be provided rolled up on a roll. Through the film, the compound described here can be formed by simply sticking the film on the respective contact surfaces. Preferably, the film is applied to each contact surface involved in the connection. Alternatively, it is preferred that the film is applied only to a contact surface involved in the connection.

The particular advantages and design features of the electrical component described above are applicable to the described use of a film and transferable, and vice versa.

In a preferred embodiment of the use of a film, the electrical component is designed as described above.

In a further preferred embodiment of the use of a film, the film is at least partially dissolved by heating.

After the film is arranged between the contact surfaces involved in the connection, and after the connection is formed (possibly under pressure), the film is no longer needed and can be removed. The dissolution of the film is preferably carried out chemically (eg, by an acid or other solvent, especially by an organic solvent) or thermally (i.e., by external heating).

In a further preferred embodiment of the use of a film, the film is formed from such a material that an adhesive bond is additionally formed by heating the film between the contact surfaces involved in the connection.

In this embodiment, the adhesive compound already described above is obtained from the material of the film. This may simplify the method of forming the connection because of additional application of e.g. B. an adhesive layer can be dispensed with.

1. a) Bereitstellen des Halbleiterchips und des Grundbauteils,
2. b) Bereitstellen einer Vielzahl von Nanodrähten auf mindestens einer der an der Verbindung beteiligten Kontaktflächen des Halbleiterchips und/oder des Grundbauteils, und
3. c) mechanisches Verbinden von zumindest zwei jeweiligen der an der Verbindung beteiligten Kontaktflächen mittels der Vielzahl der Nanodrähte.

A further aspect of the invention relates to a method for producing an electrical component having at least one base component with at least one semiconductor chip, wherein the semiconductor chip is connected to the base component, wherein a connection between respective contact surfaces of the semiconductor chip and the base component is formed via a plurality of nanowires, and wherein the method comprises at least the following method steps:

1. a) providing the semiconductor chip and the base component,
2. b) providing a plurality of nanowires on at least one of the contact surfaces of the semiconductor chip and / or the base component involved in the connection, and
3. c) mechanically connecting at least two respective ones of the contact pads involved in the connection by means of the plurality of nanowires.

The specified process steps are preferred, but not necessary, in the order given.

The particular advantages and design features of the electrical component described above and the use of a film are applicable to the method described and transferable, and vice versa.

In a preferred embodiment of the method, the electrical component is designed as described above.

In a further preferred embodiment of the method, step b) is realized for at least one of the contact surfaces by growing the nanowires on the respective contact surface.

The growth of the nanowires is preferably realized by a galvanic process. For this, the corresponding component (i.e., the semiconductor chip or the base member) is at least partially, i. in particular at least with its contact surface to be covered, introduced into a device for growing nanowires. The device may, for example, be a vacuum chamber in which nanowires can be grown by a galvanic process.

In a further preferred embodiment of the method, a protection is applied to at least one of the contact surfaces in step b), wherein in step c) the protection is at least partially removed before the contact surfaces are connected.

The protection is preferably a layer of a material that does not chemically bond with the nanowires, that provides mechanical protection for the nanowires, and that can be removed without damaging the nanowires (e.g., chemically or thermally). In particular, the protection may be a lacquer (such as PMMA or a sawing lacquer commonly used in nanotechnology). The protection may be advantageous in particular during transport of the components between the provision of the nanowires and the formation of the connection. The protection can also be referred to as transport protection.

In a further preferred embodiment of the method, step b) is realized for at least one of the contact surfaces by applying a film to the respective contact surface, the plurality of nanowires being enclosed within the film, and the film being the protection.

In particular, for this embodiment of the method, the particular advantages and design features of the use of a film described above are applicable and transferable.

In a further preferred embodiment of the method, the protection is at least partially formed with such a material that in step c) an adhesive connection is additionally formed between the contact surfaces involved in the connection.

In this embodiment, the protection has the additional function of forming the adhesive connection described above. As a result, the method can be simplified, in particular, it is possible to dispense with an additional method step, for example for applying an adhesive material, which serves for the formation of the adhesive connection.

In a further preferred embodiment of the method, the adhesive compound is formed by heating the protection.

By heating the protection, it can be at least partially removed as well as at least partially converted into the adhesive compound.

In a further preferred embodiment of the method, an oxide layer on the nanowires is at least partially removed in step c) prior to the bonding of the contact surfaces in at least one of the contact surfaces.

On the nanowires, a (natural) oxide layer can form. This can degrade the mechanical and / or thermal properties of the connection. By removing this oxide layer, therefore, the quality of the compound can be improved with respect to the aforementioned aspects. Also, a pressure necessary to form the connection can be reduced by removing the oxide layer. Removal of the oxide layer preferably occurs by use of a flux (such as an acid, particularly a reducing acid such as hydrochloric acid (HCl) or formic acid (CH ₂ O ₂ )) or by a plasma (eg, an argon plasma) , Preferably, the acid used does not contain any oxygen atoms (which could be released by chemical reactions, which could contribute to the reformation of the oxide layer). Particularly preferably, the flux also contributes to the formation of the adhesive compound. This may for example be the case with acrylates.

In a further preferred embodiment of the method, step b) is carried out for each contact surface involved in the connection.

In this embodiment, the connection between the nanowires is formed. Thereby, a particularly large contact surface of the connection (i.e., the nanowires forming it) can be achieved.

• 1: eine erste Ausführungsform einer Verbindung eines Halbleiterchips mit einem Grundbauteil,
• 2: eine zweite Ausführungsform einer Verbindung eines Halbleiterchips mit einem Grundbauteil,
• 3: eine dritte Ausführungsform einer Verbindung eines Halbleiterchips mit einem Grundbauteil,
• 4: ein zur Ausbildung einer Verbindung geeignetes Grundbauteil, und
• 5: ein elektrisches Bauteil aufweisend ein Grundbauteil mit einem Halbleiterchip.

The invention and the technical environment will be explained in more detail with reference to FIGS. The figures show particularly preferred embodiments, to which the invention is not limited. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. They show schematically:

• 1 FIG. 1 shows a first embodiment of a connection of a semiconductor chip to a base component, FIG.
• 2 FIG. 2 shows a second embodiment of a connection of a semiconductor chip to a base component, FIG.
• 3 FIG. 1 shows a third embodiment of a connection of a semiconductor chip to a base component, FIG.
• 4 a base member suitable for forming a joint, and
• 5 : an electrical component comprising a base component with a semiconductor chip.

1 shows a connection 1 a semiconductor chip 2 with a basic component 8th , where the connection 1 between contact surfaces 3 of the semiconductor chip 2 and the basic component 8th over a variety of nanowires 4 is trained. In this embodiment, the nanowires are in this embodiment 4 with both at the connection 1 involved contact surfaces 3 connected. The connection 1 According to this embodiment, z. B. be realized that the basic component 8th is provided, wherein at its contact surface 3 a variety of nanowires 4 is provided, and that the basic component 8th with the semiconductor chip 2 is connected, its contact surface 3 has no nanowires.

2 shows a connection 1 a semiconductor chip 2 and a basic component 8th , in contrast to the embodiment in 1 both involved in the connection 1 contact surfaces 3 each a variety of nanowires 4 exhibit.

This in 3 embodiment shown is the 2 very similar. Here is just an additional adhesive connection 5 between those at the connection 1 involved contact surfaces 3 educated.

4 shows a basic component 8th at a contact surface 3 a variety of nanowires 4 having. The nanowires 4 are in a slide 6 included that a protection 7 represents. The basic component 8th According to this embodiment is for forming a compound, as for example in 3 is shown, suitable and determined.

5 shows an electrical component 9 comprising a basic component 8th with a semiconductor chip 2 , The semiconductor chip 2 is with the basic component 8th connected, being a connection 1 between respective contact surfaces 3 of the semiconductor chip 2 and the basic component 8th over a variety of nanowires 4 is trained.

LIST OF REFERENCE NUMBERS

1

connection

2

Semiconductor chip

3

contact area

4

nanowire

5

adhesive connection

6

foil

7

protection

8th

basic component

9

electrical component

Claims (19)

Electrical component (9) comprising at least one base component (8) with at least one semiconductor chip (2), wherein the semiconductor chip (2) is connected to the base component (8), wherein a connection (1) between respective contact surfaces (3) of the Semiconductor chips (2) and the base member (8) via a plurality of nanowires (4) is formed. Electrical component (9) after Claim 1 , wherein the nanowires (4) are oriented perpendicular to at least one of the contact surfaces (3) involved in the connection (1). Electrical component (9) according to one of the preceding claims, wherein an adhesive connection (5) is additionally formed between the contact surfaces (3) involved in the connection (1). An electrical component (9) according to any one of the preceding claims, wherein each contact surface (3) involved in the connection (1) comprises a plurality of nanowires (4). Electrical component (9) according to one of the preceding claims, wherein the semiconductor chip (2) is formed at least partially with silicon carbide. Electrical component (9) according to one of Claims 1 to 5 in that the contact surfaces (3) provided on the base component (8) are formed at least partially with a ceramic material. Use of a film (6) for forming a connection (1) of a semiconductor chip (2) to a base component (8) of an electrical component (9), wherein the connection (1) between respective contact surfaces (3) of the semiconductor chip (2) and the Basic component (8) is formed over a multiplicity of nanowires (4), a multiplicity of nanowires (4) being enclosed within the foil (6), and the foil (6) being arranged between respective contact surfaces (3) of the semiconductor chip (2) and the base member (8). Use of a film (6) after Claim 7 , wherein the electrical component (9) according to one of Claims 1 to 6 is executed. Use of a film (6) according to one of Claims 7 or 8th wherein the film (6) is at least partially dissolved by heating. Use of a film (6) according to one of Claims 7 to 9 in that the film (6) is formed from such a material that an adhesive compound (5) is additionally formed by heating the film (6) between the contact surfaces (3) involved in the connection (1). Method for producing an electrical component (9) comprising at least one base component (8) with at least one semiconductor chip (2), wherein the semiconductor chip (2) is connected to the base component (8), wherein a connection (1) between respective contact surfaces (3 ) of the semiconductor chip (2) and of the base component (8) is formed over a plurality of nanowires (4), and wherein the method comprises at least the following method steps: a) providing the semiconductor chip (2) and the base component (8), b) providing a plurality of nanowires (4) on at least one of the contact surfaces (3) of the semiconductor chip (2) and / or the base component (8) involved in the connection (1), and c) mechanically connecting at least two respective ones of the contact surfaces (3) involved in the connection (1) by means of the plurality of nanowires (4). Method according to Claim 11 , wherein the electrical component (9) according to one of Claims 1 to 6 is trained. Method according to one of Claims 11 or 12 , wherein step b) for at least one of the contact surfaces (3) by growing the nanowires (4) on the respective contact surface (3) is realized. Method according to one of Claims 11 to 13 , wherein in step b) a protection (7) on at least one of the contact surfaces (3) is applied, and wherein in step c) the protection (7) is at least partially removed before connecting the contact surfaces (3). Method according to Claim 14 wherein step b) is realized for at least one of the contact surfaces (3) by applying a film (6) to the respective contact surface (3), the plurality of nanowires (4) being enclosed within the film (6), and wherein the film (6) represents the protection (7). Method according to one of Claims 14 or 15 , wherein the protection (7) is at least partially formed with such a material that in step c) between the contact surfaces (3) involved in the connection (1) additionally an adhesive compound (5) is formed. Method according to Claim 16 wherein the adhesive compound (5) is formed by heating the protector (7). Method according to one of Claims 11 to 17 , wherein in step c) before the bonding of the contact surfaces (3) at least one of the contact surfaces (3), an oxide layer on the nanowires (4) is at least partially removed. Method according to one of Claims 11 to 18 wherein step b) is performed for each contact surface (3) involved in the connection (1).

Images