DE102005020016B4 - Method for mounting semiconductor chips and corresponding semiconductor chip arrangement - Google Patents

Abstract

A method of mounting semiconductor chips, comprising the steps of: providing a semiconductor chip (5 ''; 5 '' ') having a surface having a diaphragm region (55; 55') and a peripheral region, said peripheral region having a mounting region (MB); Mounting the mounting area (MB) of the semiconductor chip (5 '', 5 '' ') in flip-chip technique on a surface of a carrier (1) such that an edge (K) on the surface of the carrier (1) between the Assembly area (MB) and the membrane area (55) is located; Underfilling of the mounting area (MB) with an underfill (28), wherein the edge (K) serves as a tear-off area for the underfill (28), so that no underfill (28) enters the membrane area (55); Providing a profile device (150; 160) which has a further mounting region (MB ') and an embedding region (155; 165) for at least partially embedding the semiconductor chip (5' '; 5' ''); Mounting the further mounting region (MB ') of the profile device (150; 160) on the surface of the carrier (1) in such a way that the semiconductor chip (5' '; 5' '') is at least partially embedded in the profile device (150; 160) , characterized in that the semiconductor chip (5 '', 5 '' ') in the profile device (150; 160) or the profile device (150; 160) on the carrier (1) with the semiconductor chip (5' '; 5' ' ') is clipped.

Description

STATE OF THE ART

The present invention relates to a method for mounting semiconductor chips and a corresponding semiconductor chip arrangement.

The older registration DE 10 2004 011 203 A1 discloses various examples of methods for mounting semiconductor chips and corresponding semiconductor chip arrangements, of which two examples are explained in more detail below.

3 FIG. 10 is a first example of a method of mounting semiconductor chips and a corresponding semiconductor chip device in a cross-sectional view.

In the example according to 3 is a carrier 10 as part of a premold housing 10 made of plastic, from the side of a molded therein leadframe 8th protrudes. The premold housing 10 has a recess 11 on, next to a micromechanical silicon pressure sensor chip 5 mounted in flip-chip technology overhanging. The sensor chip 5 has piezoresistive transducer elements 51 on that on a membrane 55 are housed, and an integrated circuit 52 for processing the sensor signals. For the preparation of the membrane 55 becomes a cavern 58 on the back of the relevant silicon pressure sensor chip 5 introduced, for example by anisotropic etching, z. With KOH or TMAH. Alternatively, the membrane 55 also be prepared by trench etching.

For mounting, bond pads 53 of the sensor chip 5 by means of a solder or adhesive connection, for. B. solder balls 26 in a mounting area MB on bond pads (not shown) of the premold housing 10 soldered. The mounting area MB additionally has an underfill 28 of an insulating plastic material, wherein the edge K of the recess 11 ranging between month range MB and membrane range 55 lies, as a trailing edge for the underfill 28 during the assembly process. The trailing edge K ensures that the underfill 28 not in or under the membrane area 55 can get. The membrane area 55 of the sensor chip 5 thereby protrudes laterally next to the strip-shaped mounting area MB, so that the pressure medium undisturbed to the membrane area 55 can get.

The sensor chip 5 is in the membrane area 55 on the surface by a (not shown) view, z. As a nitride layer, passivated, which acts as a secure media protection. In the mounting area MB is the sensor chip 5 through the underfill 28 protected against corrosion. The mounting area MB is substantially smaller than the total area of the sensor chip 5 , resulting in a springboard-like structure. Also, the recess extends 11 about the width of the sensor chip 5 out.

In the present example, the sensor chip 5 on the back on a glass base 140 '' Bonded, which can be relatively thin, since the lateral protruding of the sensor chip 5 in addition to the strip-shaped mounting area MB already allows the degradation of the voltage caused by different coefficients of thermal expansion of silicon and glass at the junction with the Lotkügelchen 26 and the underfill 28 arises.

The minimum distance of the leadframe 8th in the mounting area MB of the sensor chip 5 is usually greater than the minimum distance of the bond pads 53 on the sensor chip 5 , But there are only a few bond pads 53 on the sensor chip 5 are necessary, for. B. four pieces for the connection of a Wheatstone's Messbrüeke, they can be placed as far away from each other as necessary.

Finally, the premold housing has 10 an annular side wall portion 10a on top of which a lid 20 with a passage opening 15a for the pressure to be applied 10 is provided. Due to the fact that the sensor chip 5 by the flip-chip mounting on the side opposite the mounting area of the peripheral region of the top of the premold housing 10 is a smooth transfer of the applied pressure P on the membrane area 55 guaranteed.

4 FIG. 15 is a second example of a method of mounting semiconductor chips and a corresponding semiconductor chip device in a cross-sectional view.

Also at the in 4 the third embodiment shown is the sensor chip 5 ' a surface micromechanical sensor chip, which, for example, according to the in the DE 100 32 579 A1 described method was prepared and an integrated cavern 58 ' over a membrane area 55 ' having.

In this example, the glass base is completely omitted, which is a particularly space-saving design and a correspondingly low side wall area 10a allows. Assembly by means of solder balls 26 and the underfill 28 is the same as the previous example.

Unlike the previous example, the lid points 20 ' a pressure connection piece 21 in, in its passage opening 15b an optional filter 22 can be installed, which prevents particles or liquid media can get inside the sensor package. For example, it can be prevented that water penetrates, which freezes the sensor chip 5 ' could break off and destroy it.

A similar structure as the above-described pressure sensor chips 5 . 5 ' have sensor chips for an air mass meter on the thermoelectric converter principle. In such air mass sensor sensor chips, a defined temperature profile is produced in a thin, poorly heat-conducting membrane by a heater whose change, for example due to an air flow, produces a resistance change in resistors which are arranged in the vicinity of the heater. In the case of a symmetrical resistance arrangement around the heater, it is possible to detect the flow direction and thus also pulsations of the surrounding medium.

The construction and connection technology is carried out in such air mass sensor sensor chips usually by gluing the sensor chip on a holder, such as a metal sheet with a flow profile, and wire bonding for producing an electrical connection of the sensor chip and evaluation circuit (hybrid or circuit board).

A problem of this concept is that the electrical lines (bond pads on chip and circuit board, bonding wires) must be protected, which is usually done with a gel. However, this gel must not get on the sensitive surface of the sensor chip, but must protect the electrical lines safely. This requires a certain distance, in which the gel is prevented by the sword from flowing onto the chip. This necessary distance has the consequence that the sensor chip has to be made larger.

Also, the attachment of airfoils on the air mass sensor is problematic.

In Scripture DE 198 10 060 A1 For example, there is described a method of connecting a device to a substrate, wherein the substrate has an opening and the device is placed over the opening in the substrate. In this case, the component and the substrate are connected to each other by means of a solder material in such a way that a gap is established between the component and the substrate.

From the Scriptures DE 100 50 364 A1 Also, a connection between a sensor substrate and a signal processing substrate serving as a carrier substrate is known. By bump between the two substrates and a barrier provided outside the compound, an outer peripheral region is defined, which is filled with a sealing resin. As a result, a hermetically sealed space can be formed between the sensor substrate and the signal processing substrate.

ADVANTAGES OF THE INVENTION

The inventive method for mounting semiconductor chips with the features of claim 1 and the corresponding semiconductor chip arrangement according to claim 7 have over the known approaches to the advantage that a cost-effective, stable construction is made possible, wherein a smaller semiconductor chip can be used, since the electrical connections media-resistant can be laid.

The idea underlying the present invention is an overhanging structure of a sensor chip on a carrier by means of a flip-chip mounting technique, wherein a mechanical decoupling of the sensor chip is provided by the lateral overhanging and provides a profile device for additional stability and shape. The flip-chip technology makes the semiconductor chip on the carrier electrically and mechanically attached. The sensitive part of the semiconductor chip projects laterally beyond the carrier, for example into a flow channel, in the case of an air mass sensor sensor chip.

Existing manufacturing processes can largely be maintained, such. B. the semiconductor process for the sensor components and / or evaluation circuit components or sensor housing parts.

Both bulk and surface micromechanically produced sensor chips can be used. A simple assembly of the profile device, for example by gluing and / or clipping, is possible.

For the assembly of the sensor chip no gel is necessary as in the prior art. Furthermore, a synergy effect in the flip-chip assembly with, for example, a tire pressure sensor is possible.

An electrical pre-measurement in the wafer composite is possible, as well as a tape end balance after mounting on the carrier. The inventive method also allows a space-saving design of sensor chip and evaluation circuit.

In the dependent claims are advantageous developments and improvements of the respective subject of the invention.

According to a preferred refinement, a plurality of bond pads are provided in the mounting region, which are mounted on corresponding conductor tracks on the surface of the carrier via a conductive solder or adhesive connection.

According to a further preferred development, the profile device has a trench-shaped recess into which the semiconductor chip is mounted using a first adhesive layer.

According to a further preferred development, the profile device has an annular passage opening into which the semiconductor chip is mounted using a second adhesive layer.

According to a further preferred development, the further mounting region of the profiling device is mounted on the surface of the carrier using a third adhesive layer.

According to a further preferred development, the semiconductor chip is clipped into the profile device or the profile device on the carrier with the semiconductor chip.

According to a further preferred refinement, the semiconductor chip is a mass flow meter sensor chip and the profile device is a flow profile device that tapers in at least one direction.

DRAWINGS

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

It illustrate:

1a C shows a first embodiment of the method according to the invention for mounting semiconductor chips and a corresponding semiconductor chip arrangement in a lateral or frontal cross-sectional view;

2a C shows a second embodiment of the method according to the invention for mounting semiconductor chips and a corresponding semiconductor chip arrangement in lateral or frontal cross-sectional view;

3 a first example of a known method for mounting semiconductor chips and a corresponding semiconductor chip assembly in cross-sectional view; and

4 A second example of a known method for mounting semiconductor chips and a corresponding semiconductor chip arrangement in cross-sectional view.

DESCRIPTION OF THE EMBODIMENTS

In the figures, the same reference numerals designate the same or functionally identical components.

1a 5 c show a first embodiment of the method according to the invention for mounting semiconductor chips and a corresponding semiconductor chip arrangement in a lateral or frontal cross-sectional view.

In 1a denotes reference numeral 5 '' an air mass sensor chip, which is constructed analogously to the sensor chips described above 5 respectively. 5 ' , but a heater, not shown, thermosensitive resistors 51 ' and a corresponding evaluation circuit 52 ' having. As already mentioned above, a defined temperature profile is generated by the heating device, not shown, whose change, for example by an air flow, a change in resistance in the resistors 51 ' generated by the integrated evaluation circuit 52 ' is evaluated.

The sensor chip 5 '' for example, by Au plating and applying Lotkügelchen 26 on the bondpads 53 prepared for flip-chip mounting. Subsequently, he is in the mounting area MB on a support 1 , z. B. a hybrid or a printed circuit board, "face down" mounted. This is a reflow soldering, so that the solder balls 26 on the sensor chip 5 '' with tracks 100 respectively. 101 on the carrier 1 connect. After the soldering process, an underfill is added to the mechanical stability 28 For example, an elastic adhesive under the sensor chip 5 '' brought, with the underfill 28 the tracks 100 . 101 , the solder balls 26 and the bondpads 53 covers and thus ensures good media resistance of the electrical connections. The edge K serves as in the above example according to 3 as a trailing edge for the underfill 28 during the assembly process. The trailing edge K ensures that the underfill 28 not in or under the membrane area 55 can get.

The sensor chip 5 '' is thus on the support 1 attached so that it protrudes laterally and can protrude into a flow channel in which a flow ST is applied to him, for example, in an intake manifold of an internal combustion engine.

A flow profile device 150 , For example, made of sheet metal or plastic, after mounting the sensor chip 5 '' on the carrier 1 over the back of the sensor chip 5 '' and on top of the carrier 1 in a further mounting area MB 'preferably attached by gluing, soldering or clipping. In the present example, this is done by a first adhesive layer 151 which the sensor chip 5 '' with the airfoil device 150 in a trench-shaped recess 155 connects, and a second adhesive layer 152 which the flow profile device 150 in the further mounting area MB 'with the surface of the carrier 1 combines. The thus attached flow profile device 150 ensures a good flow around the membrane 55 on the sensor chip 5 '' and for a stable mount.

The other function of the air mass sensor constructed in this way can be carried out analogously to the prior art and will therefore not be explained further here.

1b and 1c show the in 1a illustrated semiconductor chip assembly in a plane or frontal cross-sectional view. Especially 1c is the polygonal configuration of the surface of the airfoil device 150 removable, which tapers towards the top and is fluidically adapted to the intended conditions.

2a 5 c show a second embodiment of the method according to the invention for mounting semiconductor chips and a corresponding semiconductor chip arrangement in a lateral or frontal cross-sectional view.

At the in 2 illustrated second embodiment is the air mass sensor sensor chip 5 ''' analogous to the micromechanical sensor chip 5 ' built, which from the DE 100 32 579 A1 is known. In particular, it has an integrated cavern 58 ' over a membrane area 55 ' on. Again, the heater is not shown, with the thermosensitive resistors 51 ' and the evaluation circuit 52 ' correspond to those of the first embodiment.

In contrast to the first embodiment, the flow profile device 160 in this embodiment with an annular passage opening 165 executed, in which the sensor chip 5 ''' with a first adhesive layer 161 is glued. A second adhesive layer 162 connects the airfoil device 160 with the surface of the carrier 1 analogous to the first embodiment.

As in the first embodiment, the airfoil device is 160 at the side of the sensor chip 5 ''' flattened, so tapers upwards, which provides the mentioned advantageous flow dynamic effect. By the execution of the flow profile device 160 with the passage opening 165 in the area of the sensor chip 5 ''' it is still possible, the airfoil device 160 flatten out.

Although the present invention has been explained above with reference to preferred embodiments, it is not limited thereto, but also executable in other ways.

In the above example, only resistive sensor structures were considered. However, the invention is also suitable for capacitive or other sensor structures in which membranes and profile devices are used.

Preferably, the membrane area exists 55 respectively. 55 ' from a poorly heat-conductive layer, for. A dielectric material such as silicon oxide, nitride or a combination thereof.

Method for mounting semiconductor chips and corresponding semiconductor chip arrangement

LIST OF REFERENCE NUMBERS 1 carrier 5, 5 ', 5 "; 5 ''' sensor chip 51 piezoresistive 51 ' thermosensitive resistor 52, 52 ' integrated circuit 53 bonding pad 55, 55 ' membrane 140 '' Wedgebase 58, 58 ' cavern 15a, 15b Through opening 20, 20 ' cover 26 solder balls 28 underfilling 10 premold housing 10a Sidewall region 8th leadframe 11 recess K edge 21 Pressure connection piece 22 filter MB assembly area MB ' additional mounting area 150, 160 Flow profile setup 151, 161 first adhesive layer 152, 162 second adhesive layer 155 depression 165 Through opening P print ST flow

Claims (12)

Method for mounting semiconductor chips, comprising the steps of: providing a semiconductor chip ( 5 ''; 5 ''' ) having a surface containing a membrane region ( 55 ; 55 ' ) and a peripheral region, the peripheral region having a mounting region (MB); Mounting the mounting area (MB) of the semiconductor chip ( 5 ''; 5 ''' ) in flip-chip technique on a surface of a carrier ( 1 ) such that an edge (K) on the surface of the carrier ( 1 ) between the mounting area (MB) and the membrane area ( 55 ) lies; Underfill the mounting area (MB) with an underfill ( 28 ), wherein the edge (K) as a demolition area for the underfill ( 28 ), so that no underfill ( 28 ) in the membrane area ( 55 ); Providing a profile device ( 150 ; 160 ), which has another mounting area (MB ') and an embedding area ( 155 ; 165 ) for at least partially embedding the semiconductor chip ( 5 ''; 5 ''' ) having; Mounting the further mounting area (MB ') of the profile device ( 150 ; 160 ) on the surface of the carrier ( 1 ) such that the semiconductor chip ( 5 ''; 5 ''' ) at least partially in the profile device ( 150 ; 160 ), characterized in that the semiconductor chip ( 5 ''; 5 ''' ) in the profile device ( 150 ; 160 ) or the profile device ( 150 ; 160 ) on the support ( 1 ) with the semiconductor chip ( 5 ''; 5 ''' ) is clipped. A method according to claim 1, characterized in that in the mounting region (MB) a plurality of bond pads ( 53 ) are provided, which via a conductive solder or adhesive bond ( 26 ) on corresponding tracks ( 100 ; 101 ) on the surface of the carrier ( 1 ) to be assembled. Method according to claim 1 or 2, characterized in that the profile device ( 150 ; 160 ) a trench-shaped recess ( 155 ) into which the semiconductor chip ( 5 '' ) using a first adhesive layer ( 151 ) is mounted. Method according to claim 1 or 2, characterized in that the profile device ( 150 ; 160 ) an annular passage opening ( 165 ) into which the semiconductor chip ( 5 ''' ) using a second adhesive layer ( 161 ) is mounted. Method according to at least one of claims 1 to 4, characterized in that the mounting of the further mounting region (MB ') of the profile device ( 150 ; 160 ) on the surface of the carrier ( 1 ) using a third adhesive layer ( 152 ; 162 ) happens. Method according to at least one of claims 1 to 5, characterized in that the semiconductor chip ( 5 ''; 5 ''' ) a mass flow sensor sensor chip ( 5 ''; 5 ''' ) and the profile device ( 150 ; 160 ) a in at least one direction tapered flow profiling device ( 150 ; 160 ). A semiconductor chip device comprising: a semiconductor chip ( 5 ''; 5 ''' ) having a surface containing a membrane region ( 55 ; 55 ' ) and a peripheral region, the peripheral region having a mounting region (MB); a carrier ( 1 ), wherein the mounting region (MB) of the semiconductor chip ( 5 ''; 5 ''' ) in flip-chip technique on a surface of the carrier ( 1 ) is mounted such that an edge (K) on the surface of the carrier ( 1 ) between the mounting area (MB) and the membrane area ( 55 ) lies; an underfill ( 28 ) for underfilling the mounting area (MB), wherein the edge (K) as a demolition area for the underfill ( 28 ), so that no underfill ( 28 ) in the membrane area ( 55 ) is present; a profile device ( 150 ; 160 ), which has another mounting area (MB ') and an embedding area ( 155 ; 165 ) for at least partially embedding the semiconductor chip ( 5 ''; 5 ''' ), wherein the further mounting region (MB ') of the profile device ( 150 ; 160 ) on the surface of the carrier ( 1 ) is mounted such that the semiconductor chip ( 5 ''; 5 ''' ) at least partially in the profile device ( 150 ; 160 ), characterized in that the semiconductor chip ( 5 ''; 5 ''' ) in the profile device ( 150 ; 160 ) or the profile device ( 150 ; 160 ) on the support ( 1 ) with the semiconductor chip ( 5 ''; 5 ''' ) is clipped. Apparatus according to claim 7, characterized in that in the mounting region (MB) a plurality of bond pads ( 53 ) are provided, which via a conductive solder or adhesive bond ( 26 ) on corresponding tracks ( 100 ; 101 ) on the surface of the carrier ( 1 ) are mounted. Apparatus according to claim 7 or 8, characterized in that the profile device ( 150 ; 160 ) a trench-shaped recess ( 155 ) into which the sensor chip ( 5 '' ) using a first adhesive layer ( 151 ) is mounted. Apparatus according to claim 7 or 8, characterized in that the profile device ( 150 ; 160 ) an annular passage opening ( 165 ) into which the semiconductor chip ( 5 ''' ) using a second adhesive layer ( 161 ) is mounted. Device according to at least one of claims 7 to 10, characterized in that the further mounting region (MB ') of the profile device ( 150 ; 160 ) on the surface of the carrier ( 1 ) using a third adhesive layer ( 152 ; 162 ) is mounted. Device according to at least one of claims 7 to 11, characterized in that the semiconductor chip ( 5 ''; 5 ''' ) a mass flow sensor sensor chip ( 5 ''; 5 ''' ) and the profile device ( 150 ; 160 ) a in at least one direction tapered flow profiling device ( 150 ; 160 ).

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