WO1999002937A1

WO1999002937A1 - Igniter

Info

Publication number: WO1999002937A1
Application number: PCT/DE1998/001779
Authority: WO
Inventors: Marten Swart; Josef Dirmeyer
Original assignee: Siemens Aktiengesellschaft
Priority date: 1997-07-09
Filing date: 1998-06-29
Publication date: 1999-01-21
Also published as: JP2000513799A; KR100396964B1; JP3648256B2; EP0993589B1; DE59805824D1; EP0993589A1; KR20010015552A

Abstract

An igniter, in particular for triggering motor vehicle passenger protection means, has an integrated circuit arrangement (21) for controlling an igniting element (31) designed as a semiconductor chip (2) and an integrated capacitor (11) for providing the energy required for igniting also designed as a semiconductor chip (1). Both chips (1, 2) are stacked in a capsule of the igniter containing an igniting powder. The dimensions of a conventional igniter can thus be maintained.

Description

description

Lighter

The invention relates to an igniter according to the preamble of patent claim 1.

A known igniter (WO 96/12926-A) contains a metal carrier over which a cap is placed. The cap and carrier together form a capsule which is filled with ignition material. A first connector pin is attached to the metal carrier, another connector pin is guided through the carrier in an electrically insulated manner and protrudes into the interior of the capsule. A semiconductor ignition element is arranged on the side of the carrier facing the ignition material and is connected in an electrically conductive manner to the further connection pin by means of a bonding wire.

An occupant protection system for a motor vehicle is known from EP 0 471 871 A1, in which a control device arranged centrally in the vehicle is connected to various protective means of the motor vehicle via a data line. In this case, an electrical circuit is assigned to each protective device, which in particular receives and decodes ignition commands sent by the central control device. Furthermore, an energy storage capacitor is arranged with each occupant protection means, so that, as a result of control signals from the control device, the electrical circuit causes the energy stored in the capacitor to be transferred to an ignition element of the occupant protection means and thus initiate triggering of the occupant protection means.

The object of the invention is a space-saving arrangement of an electrical associated with an occupant protection means To create circuit that is connected to the central control unit via a data line.

The object is achieved according to the invention by the features of patent claim 1.

The electrical circuit and the energy storage capacitor are introduced / integrated in a lighter known for example from WO 96/12926-A. So that the igniter according to the invention does not differ in shape and size from the known igniter, the electrical circuit is designed as an integrated circuit arrangement on a semiconductor substrate and, due to the integration, allows dimensions that can be clamped. Furthermore, the capacitor provided for providing energy for a starting process is also designed as an integrated component, which takes the form of a further semiconductor wafer. The first semiconductor wafer containing the capacitor is arranged with its broad side opposite the broad side of the second semiconductor wafer containing the integrated circuit arrangement, so that the semiconductor wafer is stacked on top of one another as a so-called “package” and thus takes up the smallest possible space. This package will be used again preferably arranged on a metal carrier of the igniter, which at least forms a capsule together with a cap, which is filled in the following ignition material: The two broad sides of a semiconductor plate each have a much larger area in a cuboid plate than one of the four end faces .

By designing the circuit arrangement and the capacitor as integrated components in accordance with the invention and stacking these components in accordance with the invention, all of the components which are required for an occupant protection system according to EP 0 471 871 A1 and are arranged spatially close to the occupant protection means elements in a conventional lighter. This reveals numerous advantages: Only a single plug connection between the data line, which is supplied as part of a wiring harness, and the igniter is required on the ignition side. In contrast, a separately designed adapter for receiving the electrical circuit between the wiring harness and the lighter had two plug connections: one to the wiring harness, the other to a conventional lighter. With the igniter according to the invention, the risk of insufficient contacting and inadvertent polarity reversal is thus reduced to a minimum.

Such an igniter intended for triggering an occupant protection means is usually plugged into the housing of a gas generator or otherwise mechanically connected to it. The gas generator in turn has predetermined breaking points or openings directed towards a folded airbag. By heating the ignition element in the igniter, the ignition of the igniter explodes, whereby sufficient energy is transferred to the gas generator so that its gas tablets release gas, which flows into the airbag. Gas generators usually have fastening points or openings for receiving conventional igniters with fixed geometries. If, according to the invention, the entire electronics, including the capacitor, is integrated into a conventional igniter without the size and size having to be changed, the use of conventional gas generators in conjunction with the igniter according to the invention can be used, so that, on the one hand, a structurally complex change to the gas generators is not necessary st, on the other hand, essential components of the lighter compared to conventional lighters m their design need not be changed. Metal supports, such as a cap, for example, can have a construction which is identical to that of the known igniter. Furthermore, the igniter according to the invention requires only a minimum of components and is easy to manufacture.

For the formation of a capacitor as an integrated component that can absorb sufficient energy to ignite an occupant protection agent, reference is made to the specialist article "A modern capacitor technology based on porous silicone" in Thm Solid Films by Lehmann et al A silicon substrate vertically etched a large number of pores, an applied dielectric layer and a polysilicon layer applied to the dielectric layer subsequently form the capacitor together with the substrate, the substrate and the polysilicon layer forming large-area capacitor plates due to the large number of pores. For the design and manufacture of such a capacitor, reference is made to the above-mentioned technical article, the content of which is hereby incorporated as part of the present patent application.

Advantageous developments of the invention are characterized by the subclaims.

Exemplary embodiments of the invention and its developments are explained in more detail with reference to the drawings. Show it:

1 shows an electrical circuit diagram of the igniter, FIG. 2 shows the igniter according to the invention in an exploded view from a view from above, and FIG. 3 shows an igniter according to the invention in an exploded view from a view from below.

FIG. 1 shows the electrical circuit diagram of the igniter according to the invention. For connection to a plug of the wiring harness, the connections 6 are provided on the underside, each of which a decoupling resistor 61, and a board filter ensator _d 62 with an integrated circuit device 21 are connected. Furthermore, an ignition element 31 in the form of a heating resistor and an energy storage capacitor 11 are connected to the integrated circuit arrangement 21.

The function of the individual components is explained in more detail below: Since at least two of the connections 6 are connected to a data bus on the wiring harness side, a short circuit, for example of the integrated circuit arrangement 21, paralyzed the entire bus system. To protect the bus from such a short circuit, the high-resistance decoupling resistors 61 m are provided for each connection path. The filter capacitor 62 is used to filter out high-frequency electromagnetic interference radiation. The capacitor 11 serves to provide a sufficient amount of energy to ignite or trigger the associated occupant protection means. The ignition element 31 is designed as a resistance heating wire, which is connected to a ignition material, e.g. Zundpulver, the lighter is hot-coupled. The integrated circuit arrangement 21 receives incoming messages from a central control device of the occupant protection system via the connections 6. These messages can contain trigger information but also diagnostic information. For this purpose, the integrated circuit arrangement has an interface suitable for connection to the data bus and a control unit in the form of a microprocessor for evaluating the received data, for sending the message to be sent, and for carrying out control and test routines. If the integrated circuit arrangement detects a transmitted ignition command, it switches an integrated electrically controllable one

Switch conductive, through which the energy stored in the energy storage capacitor 11 is transmitted in the form of a heating current to the ignition element 31. Figure 2 shows an exploded view of the inventive _A nz _ü nders from a top view. The erfmdungsgemaße igniter contains three terminal pins 6 which unststoffhalter by a _K 7 provided with glass insulation 51 Off- voltages of a Metalltragers 5 are guided. The metal carrier 5 serves as a carrier element for three flat semiconductor chips 1, 2 and 3. The first semiconductor chip 1 contains the integrated capacitor, the second semiconductor chip 2 the integrated circuit arrangement and the third semiconductor chip 3 the ignition element. According to FIG. 2, the second and the third semiconductor chips 2 and 3 each have contact fields 4 on their broad sides, the contact fields 4 of the second semiconductor chip 2 being arranged on a protruding surface of the second semiconductor chip 2, so that in the case of stacked semiconductor chips 2, 1 and 3 a contacting of the third semiconductor die 3 with the second semiconductor die 2 is made possible via bonding wires 41. The first semiconductor chip 1 is connected to the second semiconductor chip 2, preferably using the so-called “flip-chip technology”. For this purpose, the two semiconductor chips 1 and 2 have contact fields 4, not shown, on the broad sides facing one another, which are stacked when the two semiconductor chips are stacked together face each other and create an electrical contact between the two semiconductor chips 1 and 2.

The individual semiconductor wafers are preferably connected to one another via an adhesive layer. If necessary, an additional insulating layer is required between the individual semiconductor chips, so that electrical short circuits between the semiconductor chips representing the individual components are avoided and electrical contacts are only made in a defined manner via the contact fields. The third semiconductor chip is preferably a silicon substrate, on which a polysilicon layer with a thin cross-sectional area is applied. This thin cross-sectional area serves as a heating resistor when current flows. However, the heating resistor can also be integrated into the first semiconductor die. For this purpose, the first semiconductor wafer contains an area not penetrated by the aforementioned pores, but to which the polysilicon layer is applied, which also forms one of the capacitor electrodes. In this substrate area, the polysilicon layer is in turn formed in a defined area with a thin cross section, so that this area of the polysilicon layer forms the resistance heating element. With such a realization of the ignition element, a third semiconductor plate can therefore be dispensed with.

As an alternative to the aforementioned ignition element implementation, the second semiconductor die can also contain the ignition element. For this purpose, an area of a polysilicon layer serving as the contact layer for the electrical circuit is exposed and serves in this exposed area as a resistance heating element.

In all forms of formation of the ignition element, care must be taken that the ignition element has a good thermal coupling to the ignition material. For this reason, the semiconductor die that contains the resistance element is preferably arranged at the top. The lowermost semiconductor chip is preferably connected to the metal carrier 5 via an adhesive bond. The metal carrier 5 serves on the one hand as a heat sink for the integrated circuit arrangement. On the other hand, it serves as a mechanically stable element for the igniter. The metal support also serves as a protective shield against serious mechanical effects on the connector to the data bus or the data bus even if the ignition material explodes.

According to FIG. 3 it can be seen that the connection pins 6 each contain a decoupling resistor 61. The filter capacitor 62 is arranged between two connecting pins 6. A plastic holder only shown in the opening fixes the connecting pins 6 and the components 61 and 62.

The following advantageous manufacturing method is proposed: The connecting pins 6 are part of a stamped grid punched out of a metal sheet. After the stamping process, the components 61 and 62 are attached to the stamped grid. In the following, the plastic holder 7 is sprayed around the lead frame. Excess electrical connections between the connection pins, which served for the mechanical stability of the lead frame during component assembly, are then punched out. The device created so far with the plastic holder 7 and the connecting pins 6 is subsequently connected to the metal carrier 5, the connecting pins 6 being pressed into glass insulations 51 of the metal carrier 5. Preferably, the semiconductor wafers are already attached to the metal carrier in a stacked manner. For this purpose, the individual semiconductor wafers are glued to one another or to the metal carrier. When using flip-chip technology, the individual semiconductor wafers are already in contact with one another. Otherwise, after the metal carrier has been joined together with the semiconductor wafers and the plastic holder, 7 bond contacts are produced between the semiconductor wafers, where necessary, and bond contacts between the pins and contact fields of the integrated circuit arrangement. In the following, the cap 8 is placed on the metal carrier 5 and tightly connected to it, for example by a flanging process. The cap 8 has at its end face an opening through which the capsule formed by the cap 8 and the metal body 5 is filled, in particular pressed, in the following ignition material m. The ignition material therefore surrounds the semiconductor chips 1 to 3 in the following. The cap is then hermetically sealed with a cover (not shown).

Claims

claims

1. lighter, in particular for triggering an occupant protection means of a motor vehicle, - with an ignition element (31) interacting with ignition material, characterized by

- A first semiconductor chip (1), which contains a capacitor (11) designed as an integrated component for providing energy for an ignition process, and by

a second semiconductor chip (2) which contains an integrated circuit arrangement (21) for controlling the ignition element (31),

- Wherein the first side of the first semiconductor wafer (1) faces a broad side of the second semiconductor wafer (2).

2. Igniter according to claim 1, characterized in that the first and the second semiconductor chips (1,2) are arranged one on top of the other.

3. Igniter according to claim 1 or claim 2, characterized in that the ignition element (31) is designed as a resistance heating wire.

4. Igniter according to one of the preceding claims, characterized in that a third semiconductor chip (3) contains the ignition element (31), and that the third semiconductor chip (3) is opposite with its broad side to a broad side of the first or second semiconductor chip (1, 2) .

5. igniter according to claim 4, characterized in that the third semiconductor chip (3) on the first semiconductor chip (1) is arranged.

6. Number _ü Direction according to any one of the preceding claims, characterized in that each semiconductor die comprises (1,2,3) contact pads (4) for making electrical contact.

7. igniter according to claim 6, characterized in that the contact fields (4) of the first and the second semiconductor plate (1, 2) are connected to one another via bonding wires (41).

8. igniter according to claim 7, characterized in that the area of the second semiconductor plate (2) at least around

The area of the contact fields (4) is larger than the area of the first semiconductor plate (1).

9. igniter according to claim 6, characterized in that e- the contact field (4) is arranged on the broad side of the respective semiconductor plate (1,2,3).

10. Igniter according to claim 6, characterized in that the contact fields (4) of the first and second semiconductor plates (1, 2) rest directly on one another.

11. Lighter according to one of the preceding claims, characterized in that at least one metal carrier (5) and together a cap (8) arranged on the metal carrier (5) form a capsule for the ignition material, and that the semiconductor chips (1, 2, 3 ) are arranged one above the other on the metal support (5).

12. Lighter according to claim 11, characterized in that connection pins (6) for the integrated circuit (21) are guided electrically isolated by the metal carrier (5).