EP0657024A1

EP0657024A1 - Process for producing miniature components

Info

Publication number: EP0657024A1
Application number: EP94923705A
Authority: EP
Inventors: Graham Bailey; Gerhard Flory; Bernhard Klipfel
Original assignee: Ranco Inc of Delaware; Ranco Inc
Current assignee: Ranco Inc of Delaware; Robertshaw US Holding Corp
Priority date: 1993-06-30
Filing date: 1994-06-30
Publication date: 1995-06-14
Also published as: WO1995001557A1; DE4321804A1; CA2143641A1

Abstract

In a process for producing miniature components, especially pressure or similar sensors, consisting of at least two superimposed individual units (5, 8), a wafer (2) is produced having a plurality of individual semiconductor components (5). In addition a connecting component (4) is produced having a plurality of individual connecting units (8), in which the individual semiconductor units (5) and the individual connecting units (8) are of much the same size and are regularly arranged on the wafer (2) or the connecting component (4). All the individual units (5, 8) of the wafer (2) and the connecting component (4) are secured together in a single procedure step. This layered structure is then cut to form the miniature components. A connecting film with conductive tracks along webs can be applied to the individual semiconductor units (5) to provide their contacts.

Description

METHOD FOR PRODUCING SMALL COMPONENTS

DESCRIPTION

The invention relates to a method for producing small components, in particular pressure sensors or similar sensors, which are constructed from at least two individual units stacked on top of one another.

FIGS. 1 a to 1 c show a conventional method for producing small components 1 of this type. First, in a first method step (FIG. 1 a), a silicon wafer 2 is produced which contains a large number of semiconductor individual units 5 or wafer sub-units 6. FIG. 1 a shows a top view and a perspective view of such a semiconductor individual unit 5, all of the semiconductor individual units 5 produced on the silicon wafer 2 being constructed in an equivalent manner and arranged in a regular manner. On the surface of a single semiconductor unit 5 is one electrical circuit arrangement provided with pads 14. Furthermore, a carrier molding is produced, which contains a plurality of carrier subunits 7. The silicon wafer 2 and the carrier molding together form a composite wafer, wherein the wafer sub-units 6 and the carrier sub-units 7 made of glass together form the semiconductor individual units 5.

In a further method step (FIG. 1b), a large number of individual connection units 8 are produced. These individual connection units 8 have, for example, a projection 8-1 and a bore or cavity 8-2, as shown in FIG. 1b. After the production of a large number of such individual connection units 8, the silicon wafer 2 and the carrier molding are cut, for example with a diamond saw, in order to produce a large number of individual semiconductor individual units 5 (FIG. 1 a).

In two further process steps (FIG. 1 c), the individual individual units 6, 7 and 8 are now connected in order to produce the small components 5.

In such a manufacturing process for components, as many individual connection operations are necessary as individual semiconductor units were produced from the silicon wafer 2. In view of the fact that, for example, 200, 400 or 600 individual semiconductor individual units can be produced on a wafer, this means the corresponding number of individual connection operations, which is very time-consuming, uneconomical and costly. Also own the semiconductor individual units have extremely small dimensions, for example 2, 3 or 4 mm edge length. For the connection operations indicated in FIG. 1c, an alignment of the wafer subunit 6, carrier subunit 7 and connection individual unit 8 must be carried out, but gripping, aligning and connecting is extremely difficult and time-consuming for such small dimensions.

The object of the present invention is therefore

To create a method with which a large number of small components consisting of at least two stacked individual units can be produced in a short time, with little effort and low costs.

This object is achieved according to the invention by a method for producing small components, which is characterized by the following steps:

a) producing a wafer with a plurality of semiconductor individual units; b) producing a connection fitting with a plurality of connection individual units; c) aligning the wafer and the connection molding such that a single semiconductor unit is arranged opposite a single connection unit; d) simultaneously connecting each semiconductor unit with its respective connection unit, with the wafer and the connection molding being retained; e) Generating the small components by simultaneous

Cutting the wafer and the connection molding along separation lines between the individual connected semiconductor individual units and connection individual units.

According to the invention, a

To produce connection fitting, which has a plurality of connection individual units. Instead of connecting the individual semiconductor individual units to individual individual connection units, only a single alignment of the wafer and the connection fitting is required in the method according to the invention. This has the essential advantage that only a single work step is required to connect all the individual semiconductor units and individual connection units. This eliminates the need for individual alignment of a single semiconductor unit and a single connection unit. As long as it is ensured that the connection individual units of the connection molding are arranged as regularly as the semiconductor individual units on the wafer, only alignment of the wafer and the connection molding is required, which considerably reduces the production time (approx. 1/300). The workload is thus reduced, the production time is considerably reduced, and thus a much more cost-effective production of such small components is possible.

An advantageous embodiment of the method according to the invention can also be applied to the production of small components which consist of more than two layered details exist in that

a wafer is produced with a plurality of wafer subunits, a carrier molding is produced with a plurality of carrier subunits, the wafer and the carrier molding with mutually aligned wafer subunits and carrier subunits are connected to one another to form a composite wafer with a multiplicity of semiconductor subunits from wafer subunits and carrier subunits, and that steps d) and e) are carried out with the assembled wafer.

Even if the small components are to be constructed from a plurality of individual units stacked on top of one another, the production via a carrier molding enables only one alignment of the connecting molding, the carrier molding and the wafer to be required. The manufacturing time and the manufacturing costs are thus also reduced for the production of small components which consist of more than two individual units stacked on top of one another.

In the last-mentioned method for producing small components which consist of more than two individual units, the carrier molding can be connected to the wafer and the connecting molding simultaneously via their respective individual units in one step. The individual units are aligned beforehand. However, it is also possible to align the wafer and a carrier molding with respect to one another and to connect them first, after which a further alignment of this stack structure to the connecting molding is carried out before their connection. Since only one alignment of a wafer, the carrier molding and the connecting molding is required, the production time is also reduced considerably for the production of small components from more than two individual units.

A eutectic or anodic bonding method or another suitable method can be used for the connecting step for connecting the individual units of the wafer and the connecting shaped piece or the carrier shaped piece. This is particularly advantageous because, in this method, it is not necessary to individually access semiconductor individual units located in a central section of the wafer in order to effect their connection. The wafer and the connection molding therefore only have to be aligned with one another and moved towards one another for eutectic or anodic bonding.

In order to avoid stresses in the small components, it is advantageous that the wafer, the connection molding and optionally the carrier molding are made of materials which have the same or similar thermal expansion coefficient. For example, the wafer is made of silicon and the connection molding is made of glass, Vacon or Kovar, while the carrier molding is made of glass or Pyrex. After the small components have been produced, further connecting steps can be carried out in order to connect the small components to further holding elements. These further connection steps can include glass soldering, bonding, gluing, electron beam welding or laser welding processes. Advantageously, these further holding elements also have similar thermal expansion coefficients as the small components produced.

The small components are advantageously pressure sensors, the semiconductor individual units being produced as pressurized elements and the connecting individual units as connecting elements.

To connect the small components to an electronic evaluation unit, it is advantageous that in a further process step, a connecting film with conductor tracks leading along webs to individual connections is attached to the semiconductor individual units of the small components in such a way that the individual connections come into contact with connection pads of the semiconductor single units.

To avoid tension in the connection, the connecting film consists of a flexible material, for example polyimide.

It is advantageous for the connecting film to be connected to the individual semiconductor units by gluing, soldering or tape bonding or for contacting it with other suitable connecting methods. The connecting film is designed with the individual connections, for example punched out, in such a way that the least possible application of force to the individual semiconductor units is ensured.

The invention is explained in more detail below with reference to the drawings.

The drawings show:

Fig. La to lc a conventional manufacturing process for small components, which e.g. three stacked individual units are built up;

2a to 2f an inventive

Manufacturing process for small components;

3a to 3c an embodiment of a

Connection single unit, which is provided in the connection molding shown in Figure 2b;

4a and 4b one with the invention

Manufacturing process manufactured small component, which is connected to another holding element;

5 shows an embodiment of the manufacturing method according to the invention for manufacturing small components, which are made up of more than two stacked individual units, and

Fig. 6 shows an embodiment of the manufacturing method according to the invention, in which a connecting film with conductor tracks for connecting the semiconductor individual units via e.g. four connection points with evaluation electronics is applied to the individual semiconductor units.

In the following description of advantageous embodiments of the invention, the reference numerals designate the same or corresponding parts as in the figures la to lc.

FIG. 2 shows a manufacturing method according to the invention (hereinafter referred to as a full wafer manufacturing method) for small components which are made up of at least two individual units stacked on top of one another. These small components are pressure sensors, for example. First, as in the conventional method (FIG. 1 a), a silicon wafer 2 is produced with a multiplicity of individual semiconductor units 5, which are arranged regularly on the wafer 2 (FIG. 2 a). In addition, a connection molding 4 is produced, which contains a plurality of interconnected individual connection units or connection elements 8. Figure 2b shows one Top view and a perspective view of the connection elements 8 arranged regularly next to one another in the connection molding 4. The number and size of the connection elements 8 corresponds to the number and size of the individual semiconductor units 5.

In a next method step (FIG. 2c), the wafer processed in this way with any external dimensions (typically 4 ") and the connection fitting are aligned with one another in such a way that each semiconductor unit 5 is opposite a corresponding connection unit 8. Since the connection units 8 and the semiconductor units 5 have the same size , only two semiconductor individual units 5 and two connection individual units 8 have to be aligned with one another, so the number of semiconductor individual units 5 generated on the wafer is exactly the same number of connection individual units 8 with the same dimensions as for the Si wafer compared to the connection fitting, the respective semiconductor individual units and connection individual units being exact are brought into congruence with each other.

Now, as shown in FIG. 2, the silicon wafer and the connection fitting are connected to one another, for example by eutectic connection or another suitable connection technology, all opposite individual units being connected to one another at the same time. Thus, all semiconductor individual units are connected to their respective connection individual units in a single work step. The structure produced in this way is shown in FIG. 2d, FIG. 2e showing a side view of this layered structure. To produce the individual small components (FIG. 2f), the layered structure shown in FIG. 2d is cut along dividing lines 9, for example with a diamond saw. The connection molding 4 and the wafer 2 as well as a carrier molding 3 are cut simultaneously.

The connection molding 4 to be connected to the silicon wafer and the carrier molding 3 consist, for example, of a material which has an expansion coefficient similar to the silicon material (for example glass, Pyrex, Vacon, Kovar etc.). In this way, no unfavorable stress conditions occur when the connection molding, carrier molding and silicon wafer are connected.

FIG. 3 shows an exemplary embodiment of a connection single unit 8, which is used in particular for the production of pressure sensors. FIG. 3a shows a perspective view, FIG. 3b a side view and FIG. 3c a top view. The connection single unit 8 consists of a projecting part 8-1 and a part with a bore 8-2. The part with the bore is provided for connection to the semiconductor individual units 5 (see FIG. 2a).

As FIG. 4 shows, the shape of the individual connection units or connecting elements 8 is selected accordingly for a further connection method. This connection method to a larger bracket can be done, for example, by glass soldering, gluing to glass connection elements 8 or by Electron beam or laser welding (with connection elements 8 from Vacon or Kovar) or by a similar method. FIGS. 4a and 4b show how the small components 1 consisting of the semiconductor individual unit 5, consisting of a wafer subunit 6 and a carrier subunit 7, and the connecting individual unit 8 are connected to such further holding elements 10 made of a different material. It is advantageous if the semiconductor single unit 5, the connection element 8 and the further holding element 10 have similar expansion coefficients in order to avoid stresses in the individual connections.

Figure 5 shows an embodiment of the manufacturing method according to the invention for small components. This embodiment is intended in particular for small components which are constructed from more than two individual units stacked one on top of the other. With this method, in addition to the production of the silicon wafer 2 and the connection molding 4, an additional carrier molding 3 is produced. This carrier molding 3 carries a plurality of carrier sub-units 7, the size of the wafer sub-units 6 of the semiconductor individual units 5 and

Connection individual units 8 correspond. The further support subunits 7 of the support molding 3 can be support pieces, spacers and further electrical circuits etc. In the method shown in FIG. 5, the wafer 2, the carrier molding 3 and the connecting molding 4 are aligned with one another so that all of the individual units are opposite one another. In a further step, the wafer 2 is first connected to the carrier molding 3. Then the further connection to the connection fitting 4 takes place. This can again be done by eutectic or anodic bonding. Thereafter, the wafer 2, the carrier molding 3 and the connection molding 4 are cut simultaneously, so that a large number of small components are produced which consist of more than two individual units.

Although in FIG. 5 an alignment of the wafer 2, the carrier molding 3 and the connecting molding 4 is carried out at the same time, it is also possible to first of all the wafer

2 and to align the carrier molding 3 with respect to one another and to connect them to one another and then the composite layer 2,

Align 3 to the connection fitting 4 and connect it.

A further advantageous embodiment of the method according to the invention comprises the attachment, for example gluing or another suitable contacting method, of a connecting film 11 to the semiconductor individual units 5 of the small components 1, as shown in FIG. 6. The connecting film 11 is designed, for example punched out, so that it has individual connections 13, which in each case correspond to connection pads 14 (see also FIG. 2a) on the semiconductor individual units 5 and lie opposite them. The connecting film 11 has conductor tracks 12 along webs 15 which are connected to these individual connections 13. The conductor tracks 12 are connected, for example, to evaluation electronics for the small components 1. The connecting film 11 is provided separately for each small component 1 and has a circular shape with punched-outs. The connecting film 11 is now connected in such a way that only the individual connections 13 come to lie on the respective connection pads 14 of the semiconductor detail 5. By attaching such a connecting film, a particularly stress-free connection is established between the individual semiconductor units and the evaluation electronics. It is advantageous if the connecting film 11 consists of flexible plastic, for example polyimide. The shape of a connecting film 11 with such individual connections 13 ensures the least possible introduction of force onto the small component 1.

The full wafer production method according to the invention was described above in connection with the production of pressure sensors from silicon wafers, but it is suitable for the production of any small components.

In particular, the full-wafer production method according to the invention is suitable for the production of small components which have extremely small dimensions, for example 2, 3 or 4 mm edge length, since individual alignment of semiconductor individual units and connection individual units is difficult for such small components. The invention advantageously circumvents this problem by producing a wafer and a connecting shaped piece, only the wafer and the connecting shaped piece having to be aligned and connected to one another. The process is therefore inexpensive and enables the production of 200, 400 or 600 similar small components in the shortest possible time.

Claims

PATENT CLAIMS

1. A method for producing small components (1), in particular pressure sensors or similar sensors, which are constructed from at least two individual units (5, 8) stacked on top of one another, comprising the following steps:

a) producing a wafer (2) with a plurality of semiconductor individual units (5); b) production of at least one connection fitting (4) with a plurality of connection individual units (8); c) aligning the wafer (2) and the connection molding (4) such that in each case one semiconductor unit (5) is arranged opposite a connection unit (8), d) simultaneously connecting each semiconductor unit (5) to its respective opposite connection unit (8), wherein the wafer (2) and the connection molding (4) are retained; e) Generating the small components (1) by simultaneously cutting through the wafer (2) and the connection molding (4) along dividing lines (9) between the individual connected semiconductor individual units (5) and individual connection units (8).

2. The method according to claim 1, characterized g e k e n n z e i c h n e t that

a wafer (2) with a multiplicity of wafer subunits (6) is produced, a carrier molding (3) with a multiplicity of carrier subunits (7) is produced, the wafer (2) and the carrier molding (3) with mutually aligned wafer subunits (6) and carrier subunits (7) for forming a composite wafer with a multiplicity of semiconductor individual units (5) comprising wafer subunits (6) and carrier subunits (7) are connected to one another,

and that steps d) and e) are carried out with the assembled wafer.

3. The method according to claim 2, characterized in that wafers (2), carrier shaped piece (3) and connecting shaped piece (4) are connected simultaneously.

4. The method according to claim 2, characterized in that wafers (2), carrier shaped piece (3) and connecting shaped piece (4) are connected one after the other.

5. The method according to claim 1, characterized in that the semiconductor individual units (5) and the connecting individual units (8) by eutectic or anodic bonding or bonded together.

6. The method according to claim 1, characterized in that a further connection step is carried out after step e) in order to connect the small components (1) to further holding elements (10).

7. The method according to claim 6, characterized in that the further connecting step comprises a glass soldering, bonding, adhesive, electron beam welding or laser welding process.

8. The method according to claim 1 or 2, characterized g e k e n n z e i c h n e t that the wafer (2), the connection fitting (4) and optionally the support fitting (3) are made of materials with the same or similar thermal expansion coefficient.

9. The method according to claim 1, characterized g e k e n n z e i c h n e t that the wafer (2) made of silicon and the connecting fitting (4) made of glass, Vacon or Kovar.

10. The method according to claim 2, characterized in that the carrier molding (3) is made of glass or Pyrex.

11. The method according to claim 2, characterized in that the small components (1) are pressure sensors, the semiconductor individual units (5) being produced as pressurized elements and the connecting individual units (8) as connecting elements.

12. The method according to any one of the preceding claims, characterized in that in a further method step, a connecting film (11) with along webs (15) to individual connections (13) leading conductor tracks (12) such on the semiconductor individual units (5) of the small components (1) is attached that the individual connections (13) come to rest on contact pads (14) of the semiconductor individual units (5).

13. The method according to claim 12, characterized in that the connecting film (11) is produced from polyimide or another flexible material.

14. The method according to claim 12 or 13, characterized in that the connecting film (11) is connected to the semiconductor individual units (5) by gluing, soldering or tape bonding or is contacted with other suitable connecting methods.