阅读说明：本技术 键合垫层系统、气体传感器和用于制造气体传感器的方法 (Bonding pad system, gas sensor and method for manufacturing gas sensor ) 是由 M·克瑙斯 H·内德尔曼 B·克莱因 V·孔德拉绍夫 R·巴拉基 M·拉皮萨 H·韦伯 于 2018-06-14 设计创作，主要内容包括：本发明建立键合垫层系统(1)、气体传感器和用于耐高温的键合垫层系统(1)的制造方法。键合垫层系统(1)沉积在作为基底的半导体芯片、例如微机械半导体芯片(11)上,在该微机械半导体芯片中集成有由介电层(13、14)组成的至少一个悬置的介电膜片、铂印制导线(10)和由铂制成的加热件(15)。在此,首先进行钽层(6)的沉积,在该钽层上进行第一铂层(5)的沉积,在该第一铂层上进行氮化钽层(4)的沉积,在该氮化钽层上进行第二铂层(3)的沉积,并且在该第二铂层上进行金层(2)的沉积,其中,在金层(2)中构造用于与键合线(8a)连接的至少一个键合垫(8)。键合垫(8)基本上位于半导体芯片(11)上的接触孔(9)的区域中和/或位于该区域外部,在该区域中借助于环形接触部实现引导至加热件(15)的铂印制导线(10)的连接。(The invention relates to a bonding pad system (1), a gas sensor and a method for producing a bonding pad system (1) resistant to high temperatures. The bond pad system (1) is deposited on a semiconductor chip as a substrate, for example a micromechanical semiconductor chip (11), in which at least one suspended dielectric membrane consisting of dielectric layers (13, 14), platinum conductor tracks (10) and a heating element (15) made of platinum are integrated. In this case, a tantalum layer (6) is deposited first, a first platinum layer (5) is deposited on the tantalum layer, a tantalum nitride layer (4) is deposited on the first platinum layer, a second platinum layer (3) is deposited on the tantalum nitride layer, and a gold layer (2) is deposited on the second platinum layer, wherein at least one bonding pad (8) for connecting to a bonding wire (8a) is formed in the gold layer (2). The bonding pads (8) are located substantially in and/or outside the region of the contact holes (9) on the semiconductor chip (11), in which the connection of the platinum conductor tracks (10) leading to the heating elements (15) is effected by means of annular contacts.)

1. Bonding pad layer system (1), comprising:

a semiconductor chip (11) as a substrate on which are deposited in sequence:

a tantalum layer (6) formed on the substrate,

a first layer (5) of platinum,

a tantalum nitride layer (4) formed on the substrate,

a second platinum layer (3), and

a layer (2) of gold,

wherein at least one bonding pad (8) for connecting to a bonding wire (8a) is formed in the gold layer (2).

2. Bonding pad system (1) according to claim 1, wherein the semiconductor chip (11) is a micromechanical semiconductor chip in which at least one suspended dielectric membrane comprising dielectric layers (13, 14), platinum conductor tracks (10) and heating elements (15) made of platinum are integrated.

3. Bonding pad system (1) according to claim 1 or 2, wherein at least one bonding pad (8) is located substantially in the region of a contact hole (9) on the semiconductor chip (11), in which contact hole an electrical contact of a platinum conductor track (10) leading to the heating element (15) is effected by means of an annular contact.

4. Bonding pad layer system (1) according to claim 1, 2 or 3, wherein at least one bonding pad (8) is located substantially in an area outside the contact hole (9) on the semiconductor chip (11).

5. Bonding cushion system (1) according to any one of the preceding claims,

the layer thickness of the tantalum layer (6) is 2-200 nanometers,

the layer thickness of the first platinum layer (5) is 50-1000 nm,

the layer thickness of the tantalum nitride layer (4) is 2-200 nanometers,

the layer thickness of the second platinum layer (3) is 2-400 nm, and

the layer thickness of the gold layer (2) is 50-1000 nm.

6. Bonding cushion system (1) according to any one of the preceding claims,

the layer thickness of the tantalum layer (6) is 5-50 nanometers,

the layer thickness of the first platinum layer (5) is 100-500 nm,

the layer thickness of the tantalum nitride layer (4) is 5-50 nanometers,

the layer thickness of the second platinum layer (3) is 10-150 nm, and

the layer thickness of the gold layer (2) is 200-600 nm.

7. Bonding pad system (1) according to any of the preceding claims, wherein tantalum (Ta) and nitrogen (N) are used ₂) The layer composition of the tantalum nitride layer (4) is in Ta _xN _yWherein x can vary between 1 and 5 and y can vary between 0.04 and 6.

8. Bonding pad system (1) according to any of the preceding claims, wherein the layer composition of the tantalum nitride layer (4) is stoichiometric.

9. Bonding pad system (1) according to one of the preceding claims, wherein the tantalum layer (6) and the first platinum layer (5) are configured as electrodes (7a) and as conductor tracks (7 b).

10. Gas sensor comprising at least one bonding pad system (1) according to the preceding claim and paste dots (7).

11. Method for manufacturing a gas sensor comprising a bonding pad system (1) and paste dots (7), the method having the steps in the following order:

a) providing a micromechanical semiconductor chip (11) as a substrate, in which at least one suspended dielectric membrane consisting of dielectric layers (13, 14) and platinum conductor tracks (10) for the electrical contacting of a heating element (15) made of platinum are integrated,

b) a tantalum layer (6) is deposited,

c) a first platinum layer (5) is deposited,

d) a tantalum nitride layer (4) is deposited,

e) depositing a second platinum layer (3),

f) a gold layer (2) is deposited,

g) at least one bonding pad (8) for connecting to a bonding wire (8a) is formed on the gold layer (2) in the region of a contact hole (9) on the semiconductor chip (11), in which contact hole a connection to a platinum conductor track (10) leading to the heating element (15) is made by means of a ring contact, and at least one bonding pad (8) for electrical contacting of the electrode structure 7a and the conductor track 7b is formed outside the contact hole (9).

h) The electrode structure 7a and the conductor tracks 7b are structured,

i) structuring paste dots (7), and

j) sintering the paste dots (7).

12. The method according to claim 11, wherein the tantalum nitride layer (4) is formed by a temperature treatment of the tantalum layer in an ammonia/hydrogen atmosphere or in a nitrogen/hydrogen atmosphere at a temperature exceeding 600 ℃.

13. Method according to one of claims 11 or 12, wherein the tantalum layer (6) and the first platinum layer (5) are constructed as an electrode structure (7a) and as a conductor track (7b) by etching, wherein the etching is carried out by means of IBE etching, plasma etching, wet-chemical etching and combinations of these etching methods.

Technical Field

The invention relates to a bonded mat system, a gas sensor and a method for manufacturing a gas sensor.

Background

Although any micromechanical component can be used, the invention and the problems based on the invention are explained with reference to a component having a gas sensor chip.

In the production of micromechanical gas sensors, a paste spot is usually applied to the electrodes after the production of a micromechanical chip with a suspended dielectric diaphragm in which a heating structure made of platinum is present and on which an interdigital electrode structure is also present, which paste spot changes its electrical resistance, for example, when a defined gas is in the vicinity of the paste spot, as described in EP 0859231 a 1.

After the paste dot has been applied, it must be sintered in order to be able to remove the organic paste component and to set the desired gas sensitivity. The sintering generally takes place at temperatures which can significantly exceed 400 ℃, as described in DE 102015209267 a 1. Since the micromechanical substructure/sensor chip is already completely processed during the sintering of the paste, it must be able to withstand the sintering process without functional impairment. This also means that the bond pads and the bond pad connections to the plane of the conductor tracks should not decompose during the sintering process.

There are already gas sensors on the market which are manufactured in a micromechanical manner, in which they are bonded by means of gold bonding wires to the platinum layer of a tantalum/platinum-bonded underlayer system. However, this system is not sufficiently process-stable and has, for example, strongly dispersed values of bond wire attachment.

It is advantageous to design a layer system in which the bondability (bond wire attachment) is sufficiently process-stable to be able to ensure mass production.

The conductor track contacting method described in DE 19824400 a1 in relation to micromechanical air mass sensor chips is also used in the realization of such a layer system, in order to be independent of possible conductor track interruptions due to edge tearing at the contact hole edge. Like the gas sensor chip, the air mass sensor chip also has a suspended dielectric diaphragm, in which a heating structure made of platinum is integrated. In the printed conductor contact method described in DE 19824400 a1, aluminum bonding pads are applied to the greatest possible extent in the contact holes and the electrical connection of the platinum printed conductors leading to the heating elements is carried out within the contact holes by means of annular contacts. The aluminum bond pad is thus applied partially on the platinum layer inside the contact hole and on the layer of the dielectric layer system lying below the platinum layer. This type of contact ensures that edge tearing at the contact hole, which occurs as a result of disadvantageous etching of the side walls, does not lead to an interruption of the electrical contact of the platinum heating structure.

Disclosure of Invention

The present invention realizes the bonding pad system according to claim 1, the gas sensor according to claim 10, and the method for manufacturing a gas sensor according to claim 11.

Thus, according to a first aspect, the present invention is directed to a bonding pad layer system on a semiconductor chip. The semiconductor chip can be, for example, a micromechanical semiconductor chip in which at least one suspended dielectric membrane with a heating element made of platinum is integrated. In the manufacture of the bond pad system, a tantalum layer is first deposited, a first platinum layer is deposited on the tantalum layer, a tantalum nitride layer is deposited on the first platinum layer, a second platinum layer is deposited on the tantalum nitride layer, and a gold layer is deposited on the second platinum layer, the gold layer serving to realize the bond pad. The gold bond pads can be connected to bond wires, wherein the entire bond pad layer system can be located on the semiconductor chip and there essentially in the region of the contact holes, in which the connection of the platinum conductor tracks leading to the heating element is effected by means of the annular contact. Furthermore, it is conceivable that the bonding pads formed from the above-mentioned bonding pad layer system are also located outside the contact hole region on the semiconductor chip and serve for electrical contacting of the electrode structure.

According to a second aspect, the invention relates to a gas sensor comprising at least one bonding pad system according to the first aspect and a paste dot (Pastendot).

According to a third aspect, the invention relates to a method for manufacturing a gas sensor comprising a bond pad system and a paste spot, the method having the steps in the following order: providing a semiconductor chip as a substrate, for example a micromechanical semiconductor chip, in which at least one suspended dielectric membrane with a heating element made of platinum is integrated, depositing a tantalum layer, depositing a first platinum layer, depositing a tantalum nitride layer, depositing a second platinum layer, depositing a gold layer, forming at least one bond pad for connection to a bond wire on the gold layer, forming an electrode structure, forming a paste dot and sintering the paste dot.

Preferred embodiments are the subject matter of the respective dependent claims.

The invention provides a bonding pad system, a gas sensor and a corresponding manufacturing method, the bonding pad system comprising a specific layer sequence which is resistant to high temperatures and enables a reliable, stable and mass producible wire bond connection in a back-end process after sintering of a paste dot. By "high temperature resistant" is understood in particular that the functionality of the bond pad layer system and the gas sensor remains stable with respect to their performance even when they are exposed to temperatures at which the paste dots used for manufacturing the gas sensor are sintered. The temperature here is in particular in the range from 400 ℃ and above 400 ℃.

Because the invention enables the production of a high temperature resistant bond pad system, which can be used for example for mass produced gas sensors.

According to a preferred embodiment, the semiconductor chip is a micromechanical semiconductor chip in which at least one suspended dielectric membrane comprising a dielectric layer, platinum conductor tracks and a heating element made of platinum are integrated. This enables a plurality of application possibilities of the layer system.

According to a preferred embodiment, the at least one bonding pad is located substantially in the region of a contact hole on the semiconductor chip, in which connection of a platinum conductor track leading to the heating element is effected by means of an annular contact.

According to a preferred embodiment, the at least one bonding pad is located substantially in a region outside the contact hole on the semiconductor chip. Connections to the heating elements and/or additional electrode structures and conductor tracks can thereby be realized.

As mentioned, the refractory bond pad system has a layer sequence of tantalum/platinum 1/tantalum nitride/platinum 2/gold. According to a preferred embodiment, the layer thickness of the tantalum layer is 2 to 200 nm, the layer thickness of the first platinum layer is 50 to 1000 nm, the layer thickness of the tantalum nitride layer is 2 to 200 nm, the layer thickness of the second platinum layer is 2 to 400 nm, and the layer thickness of the gold layer is 50 to 1000 nm. The layer thickness can thus be optimally adapted to the sintering process, for example, in order to prevent undesired diffusion processes or to ensure a defined function.

According to a preferred embodiment, the layer thickness of the tantalum layer is 5 to 50 nm, the layer thickness of the first platinum layer is 100-500 nm, the layer thickness of the tantalum nitride layer is 5 to 50 nm, the layer thickness of the second platinum layer is 10-150 nm, and the layer thickness of the gold layer is 200-600 nm. By an optimized adaptation of the layer thicknesses with respect to the desired function or the sintering process applied, shorter process times and less material consumption during deposition can be achieved.

According to a preferred embodiment, tantalum (Ta) and nitrogen (N) ₂) The layer composition of the tantalum nitride layer is in Ta _xN _yWherein x is between 1 and 5 and y is between 0.04 and 6. The diffusion behavior of atoms through the tantalum nitride layer can be influenced or hindered by the selected layer composition.

According to a preferred embodiment, the layer composition of the tantalum nitride layer is stoichiometric. Whereby the diffusion of atoms of the further layer through the tantalum nitride layer during sintering can be controlled.

According to a preferred embodiment, the tantalum layer and the first platinum layer of the bonding mat system are also used for producing electrical conductor tracks and electrodes, for example in the form of interdigitated structures. This makes it possible to build accurate microelectronic components with low power consumption in a minimum of space.

According to a preferred embodiment, at least one bond pad for connection to a bond wire is formed outside the region of the contact hole on the first platinum layer of the bonding pad layer system. In this way, consisting of a tantalum layer and a first platinum layer of a bonding pad layer systemThe conductor tracks leading to the electrode structures can be electrically connected reliably and stably for a long time by means of the bonding wires. While the tantalum nitride layer is produced in a standard manner by means of reactive sputtering techniques, according to a preferred embodiment of the method according to the invention, the tantalum nitride layer can also be produced by applying the tantalum layer in ammonia (NH) at a temperature of more than 600 ℃ ₃) Hydrogen (H) ₂) In the atmosphere or in nitrogen (N) ₂) Hydrogen (H) ₂) Temperature treatment in the atmosphere. This enables a particularly precise adjustment of the composition of the tantalum nitride layer.

According to a preferred embodiment of the method according to the invention, the tantalum layer and the first platinum layer are formed as conductor tracks and electrode structures, for example as interdigitated structures, by means of a photoresist mask and a subsequent etching step, wherein the etching can be carried out by means of IBE etching, plasma etching, wet-chemical etching and combinations of these etching methods.

Drawings

The invention will be explained in detail below with reference to embodiments illustrated in the drawings. Shown here are:

FIG. 1 is a schematic view of a gas sensor according to a first embodiment of the present invention;

FIG. 2 is a schematic view of a bonding pad system according to a second embodiment of the present invention; and

FIG. 3 is a schematic flow chart diagram illustrating a method for manufacturing a bonding pad system or a gas sensor according to further embodiments.

In the drawings, like reference numbers indicate identical or functionally identical elements.

Detailed Description

Fig. 1 is a schematic view of a gas sensor according to a first embodiment of the present invention.

The realization possibility of a gas sensor according to the invention is shown, comprising a bond pad system 1, which comprises a micromechanical semiconductor chip 11 with a cavity 12 as a substrate, two dielectric layers 13 and 14, a platinum conductor track 10 leading to a heating element 15 in the cavity region 12, a tantalum layer 6, a first platinum layer 5 deposited on the tantalum layer, a tantalum nitride layer 4 deposited on the first platinum layer, a second platinum layer 3 deposited on the tantalum nitride layer, a gold layer 2 deposited on the second platinum layer, wherein the individual layer deposition is carried out over the entire surface, also via contact holes 9, and the subsequent structuring of the individual layers is carried out by means of standard methods. Bond pads 8, bond wires 8a, paste dots 7 are also drawn and electrode structures (e.g. interdigitated structures) 7a and printed wires 7b are schematically drawn. The bonding pads 8 can be formed substantially in the region of the contact holes 9, in particular directly above the contact holes, or else be arranged outside the contact holes 9.

Dielectric film layers 13 and 14 may comprise silicon dioxide (SiO) ₂) Silicon nitride (Si) ₃N ₄) And mixtures thereof and each dielectric film layer itself is composed of multiple dielectric layers or different dielectric layer sequences.

The core of the invention is the realization of a bonding pad 8 in which a bonding wire 8a made of gold can be reliably fixed on the gold layer 2 after the sintering process. Wire bonding of gold wires on gold bonding pads is applied in a standard manner when integrating the electrical connections of semiconductor chips. Here, however, the bond pads are no longer exposed to temperatures in excess of 400 ℃ after fabrication. Since gold diffuses strongly into platinum and tantalum at high temperatures and under defined atmospheric conditions and deteriorates the adhesion of the bonding pads 8 to the mount, according to the invention a tantalum nitride layer 4 is also embedded as a diffusion barrier between the gold layer 2 and the first platinum layer 5 ("platinum 1") and the tantalum layer 6 located below the gold layer, as is shown in fig. 1. Due to the suitable adhesion of gold to tantalum nitride, a second platinum layer 3 ("platinum 2") is additionally inserted as an adhesion layer between the gold layer 2 and the tantalum nitride layer 4, which acts as a diffusion barrier. From the above, therefore, a bond pad system is obtained, which is formed as follows: tantalum/platinum 1/tantalum nitride/platinum 2/gold. The bonding pad system is located with tantalum 6 as a first layer deposit on the semiconductor chip 11 with the cavity 12, the dielectric layers 13 and 14 and the platinum conductor tracks 10 or in the contact holes 9 present there.

When manufacturing the gas sensor, the electrode 7a can be manufactured with other parts of the layer system 1. In this way, for example, the tantalum layer 6 and the first platinum layer 5 can be formed as an electrode 7a and a conductor track 7b in the diaphragm region and outside the diaphragm region by targeted use of an etching mask and an etching process, onto which the paste dot 7 can subsequently be deposited. In the bond pad region, outside the membrane, on the first platinum layer 5 and the tantalum layer 6, there is also a tantalum nitride layer 4, a second platinum layer 3 and a gold layer 2, which results in the bond pad system already described above: tantalum/platinum 1/tantalum nitride/platinum 2/gold.

If the prior art construction of semiconductor chips, for example of micromechanical air mass sensors, is used, the substrate for the gas sensor chip can be produced by means of a suitable mask. Since aluminum and platinum already react with one another at relatively low temperatures (200-: chemically unstable aluminum is replaced by a chemically stable material such as gold or platinum.

Thus, the bonding pad system 1 uses platinum and gold as components of a new, high temperature stable bonding pad system 1. In order to be able to ensure good adhesion of the first platinum layer 5 of the layer system to the layers of the dielectric layers 13 and 14 of the semiconductor chip, a tantalum layer 6 is first deposited on the semiconductor chip. This tantalum layer contacts (in the manner of a ring contact) the platinum conductor track supply 10 of the heating element 15 made of platinum in the contact hole 9 and also serves as an adhesion layer for the subsequent layers on the dielectric layers 13 and 14. A tantalum nitride layer 4, a second platinum layer 3 and a gold layer 2 are subsequently deposited on this tantalum layer 6 and the first platinum layer 5 and the overall layer system is structured. The deposition of the individual layers is carried out by means of sputtering, reactive sputtering, Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), pulsed laser redeposition and/or Atomic Layer Deposition (ALD). Process cost and time can be optimized by selecting an appropriate deposition process.

In the presence of a suitable process implementation and a correspondingly adapted mask, the deposited layers can also be structured in such a way that electrode structures (for example interdigitated structures) 7a and conductor tracks 7b are produced, which consist of a sequence of a first platinum layer 5 and a tantalum layer 6. In general, this takes place here in such a way that the gold layer 2, the second platinum layer 3 and the tantalum nitride layer 4 are structured by means of a first mask plane and subsequently the first platinum layer 5 and the tantalum layer 6 are structured by means of a second mask plane. The bonding structure, which is then produced by the first mask plane, is also used for electrical contacting of the electrode 7a, while the second mask plane is used for producing the electrode 7a, the electrical supply of this electrode, and also for realizing the final bonding pad 8 in the region of the contact hole 9 and the final bonding pad 8 outside the contact hole region 9. In this way, the layer sequence of the first platinum layer 5 and the tantalum layer 6 (which is a component of the bonding pad system 1 according to the invention) is used simultaneously for producing the electrodes 7a and the electrical conductor tracks 7b on a semiconductor chip which functions as a sensor chip.

The structuring of the individual layers can be carried out by means of masks and standard etching methods, such as IBE etching, plasma etching, wet-chemical etching or a combination of these etching methods. A wet chemical etching step may for example be used to space the edges of the gold layer 2 from the edges of the second platinum layer 3 and the tantalum nitride layer 4. In this way, it can be ensured that gold cannot diffuse via the edges of the second platinum layer 3 and the tantalum nitride layer 4 and reaches uncontrolled into the first platinum layer 5 or the tantalum layer 6. The layer thicknesses and layer compositions of the individual layers can be further adapted to the sintering conditions (temperature, atmosphere, time).

This can extend the diffusion path by increasing the layer thickness, for example. That is, atoms of a substance take longer to diffuse through another substance. Since the interdiffusion of the substances is temperature and/or time dependent, an increase in the layer thickness enables a sintering process that can be carried out at higher temperatures and/or times.

Typical layer thicknesses here lie in the range from a few nanometers to a few micrometers. Preferred layer thicknesses lie in the range 2 to 200 nm for the tantalum layer 6, in the range 50 to 1000 nm for the first platinum layer 5, in the range 2 to 200 nm for the tantalum nitride layer 4, in the range 2 to 400 nm for the second platinum layer 3 and in the range 50 to 1000 nm for the gold layer 2. Particularly preferred layer thicknesses lie in the range from 5 to 50 nm for the tantalum layer 6, in the range from 100-50 nm for the first platinum layer 5, in the range from 5 to 50 nm for the tantalum nitride layer 4, in the range from 10 to 150 nm for the second platinum layer 3 and in the range from 200-600 nm for the gold layer 2.

Basically two aspects are to be considered when selecting the layer thickness. I.e. the necessary sintering conditions (temperature, atmosphere, time) and the process costs required for producing the layer. If smaller layer thicknesses can be used, this means shorter process times during deposition, less material consumption and also shorter process times during structuring of the layer. Since these three points result in a low process outlay, it is endeavoured to select the optimum layer thickness for the respective sintering conditions with regard to outlay and function. In the tantalum nitride layer 4, the layer composition is again important, which has an influence on the diffusion behavior of atoms through the layer. Therefore, the layer composition of the tantalum nitride layer 4 can be favorably changed depending on the sintering conditions. Here, the change may be located within the following range: ta _xN _yWherein x is more than or equal to 1 and less than or equal to 5 and y is more than or equal to 0.04 and less than or equal to 6. Preferably, however, a stoichiometric composition of the tantalum nitride layer 4 is sought. As already described above, the tantalum nitride layer 4 can be produced, for example, by sputtering. However, it is also conceivable for the tantalum nitride layer 4 to be formed by depositing the tantalum layer in ammonia (NH) at temperatures above 600 ℃ ₃) Hydrogen (H) ₂) In an atmosphere of (C) or in nitrogen (N) ₂) Hydrogen (H) ₂) The temperature treatment in (1).

Fig. 2 is a schematic view of a bonding pad system according to a second embodiment of the present invention.

The invention relates to a bond pad system 1 comprising a micromechanical semiconductor chip 11 as a substrate, two dielectric layers 13 and 14, platinum conductor tracks 10 of a heating element 15, a tantalum layer 6, a first platinum layer 5 deposited on the tantalum layer, a tantalum nitride layer 4 deposited on the first platinum layer, a second platinum layer 3 deposited on the tantalum nitride layer, a gold layer 2 deposited on the second platinum layer. Unlike the first embodiment, the bonding wire 8a and the bonding pad 8 are formed outside the contact hole 9 here.

As shown in fig. 2, it is basically also conceivable to form a conventional contact hole 9, in which a platinum conductor track supply 10 leading to a heating element 15 is in contact with the proposed bonding pad system 1 and to provide a bonding wire 8a and a bonding pad 8 on the bonding pad system 1 outside the contact hole 9.

Fig. 3 shows a schematic flow diagram for explaining a method for producing a bonding pad layer system or a gas sensor according to a further embodiment. The method according to fig. 3 is suitable for producing the devices described above and can be modified according to all the variants and embodiments described in relation to these devices and vice versa.

In step S01, a semiconductor chip, for example a micromechanical semiconductor chip 11, is provided as a substrate, in which at least one suspended dielectric membrane, consisting of dielectric layers 13, 14, platinum conductor tracks 10 and heating elements 15 made of platinum, is integrated. In step S02, a tantalum layer 6 is deposited. A first platinum layer 5 is deposited in step S03. In step S04, a tantalum nitride layer 4 is deposited. A second platinum layer 3 is deposited in step S05. In step S06 a gold layer 2 is deposited. In step S07, bond pads 8 for connection to bonding wires 8a are formed in the gold layer 2, substantially in the region of contact holes 9 on the semiconductor chip 11, in which contact holes the connection of the platinum conductor tracks 10 leading to the heating elements 15 is effected by means of annular contacts. Furthermore, a bonding pad can also be provided outside the contact hole region 9 in this step. In step S08, electrode structures 7a and conductor tracks 7b are produced. The paste dots 7 are constructed in step S09. The paste dot 7 is sintered in step S10. Steps S01 to S10 are preferably performed in the order of their numbering. A bonding wire 8a may be mounted on the bonding pad 8.

Although the present invention has been described with reference to preferred embodiments, the present invention is not limited thereto. The materials and the topological results mentioned are in particular only exemplary and are not limited to the examples illustrated.

Other particularly preferred applications for the bond pad system according to the invention are, for example, gas sensors, which are used, for example, in exhaust gas sensors in the automotive industry or the like.