Component which can be produced at wafer level and method of production

Abstract

A component which can be produced at wafer level has a first chip and a second chip connected thereto. The connection is (at least partially) established via a first and a second connecting structure and a first and a second contact structure of the second chip. An adaptation structure between the first chip and the first connecting structure equalizes a height difference between the first and the second contact structure.

Claims

1. A component comprising: a first chip having an upper side; a second chip having a lower side, the second chip being a MEMS chip; a first connecting structure and a second connecting structure on the upper side of the first chip; a first contact structure and a second contact structure on the lower side of the second chip; and an adaptation structure between the first chip and the first connecting structure, wherein the first connecting structure is connected to the first contact structure and the second connecting structure is connected to the second contact structure through metallizations on the connecting structures and a solder material on the metallizations, wherein the connecting and contact structures have the same height, wherein a contact surface of the second contact structure is more remote from the lower side of the second chip than a corresponding contact surface of the first contact structure, wherein a thickness of the adaptation structure is equal to a difference in distances between the contact surfaces of the contact structures and the lower side of the second chip given by way of MEMS structures on the lower side of the MEMS chip, and wherein the adaption structure is a single integral piece directly connected to the upper side of the first chip.

2. The component according to claim 1, wherein the first chip is an ASIC chip, wherein the second chip comprises an electrically conductive membrane, a counter electrode, and a back volume, and wherein the component is a microphone.

3. The component according to claim 1, wherein circuit elements of the first chip are interconnected with circuit elements of the second chip via the connecting structures and the contact structures.

4. The component according to claim 1, further comprising a frame structure that is complete or has a lateral opening, wherein the frame structure is formed by one of the connecting structures, one of the contact structures, or a further frame-shaped structure.

5. The component according to claim 1, wherein one of the connecting structures or one of the contact structures serves as a support structure.

6. The component according to claim 1, further comprising a support structure separate from the connecting structures and the contact structures.

7. The component according to claim 1, further comprising an electromagnetic shield for the first chip, the second chip, or the entire component.

8. The component according to claim 7, wherein a body of the first chip and a body of the second chip are not directly interconnected via the shield.

9. The component according to claim 1, wherein the first chip is an ASIC chip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The component or a method for producing a component will be explained in greater detail hereafter on the basis of schematic exemplary embodiments and associated figures. In the figures:

(2) FIG. 1 shows a component B having a first chip CH1, a second chip CH2, and a connection of the chips by means of connecting structures VS, contact structures KS, and an adaptation structure AS;

(3) FIG. 2 shows a possible arrangement of a bond frame and connecting and support structures of an embodiment having an acoustic channel AC through the first chip;

(4) FIG. 3 shows an embodiment having a bond frame and connecting and support structures and an acoustic channel through a non-closed bond frame;

(5) FIG. 4 shows the upper section of a component associated with FIG. 2;

(6) FIG. 5 shows the upper section of a component associated with FIG. 3;

(7) FIG. 6 shows a cross section through a first chip having an acoustic channel;

(8) FIG. 7 shows an intermediate step during the production of a component;

(9) FIG. 8 shows a further intermediate step;

(10) FIG. 9 shows a further intermediate step;

(11) FIG. 10 shows a further intermediate step;

(12) FIG. 11 shows a further intermediate step;

(13) FIG. 12 shows the further intermediate step of FIG. 11 illustrated by the arrangement of the chips in multiple panels;

(14) FIG. 13 shows a further intermediate step;

(15) FIG. 14 shows a further intermediate step;

(16) FIG. 15 shows a further intermediate step; and

(17) FIG. 16 shows a final product of a production method for providing a MEMS microphone.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(18) FIG. 1 schematically shows a cross section through a component B having a first chip CH1 and a second chip CH2. The first chip CH1 has an upper side OS, which faces toward the second chip CH2. The second chip CH2 has a lower side US, which faces toward the first chip. Both chips can comprise corresponding sides facing away from the respective other chip. However, it is also possible that the chips have an unconventional shape on the corresponding side facing away and have laterally beveled outer sides, for example.

(19) The second chip CH2 is a MEMS chip having MEMS structures MS on the lower side US of the second chip CH2. A connection and interconnection of the two chips CH1, CH2 is performed via a first and second connecting structure VS1, VS2 and via a first contact structure KS1, KS2. In order that the corresponding connecting and contact structures can be produced in a simple manner and accordingly using similar method steps, they advantageously have the same height and comprise the same material. Since the MEMS structures MS on the lower side US of the second chip CH2 can now cause the necessity of the contact surfaces of the second contact structure KS2 to be more remote from the lower side US of the second chip CH2 than the corresponding contact surface of the first contact structure KS1, and since first and second connecting structures VS1, VS2 of equal height are advantageous with respect to the processing, a direct arrangement of the two connecting structures VS1, VS2 on the upper side OS of the first chip CH1 would not result in optimum connection of the two chips. Accordingly, at least under the first connecting structure VS1, an adaptation structure AS is arranged, which equalizes the different distance of the connecting surfaces of the contact structures to the lower side of the second chip. The thickness of the adaptation structure Δh is therefore preferably essentially equal to the difference of the distances of the contact surfaces of the contact structures to the lower side US of the second chip CH2.

(20) If the adaptation structure is absent, a component having chips connected “diagonally” could thus result if the connecting structures and the contact structures would only represent locally arranged connecting elements. However, if it is desirable to enclose the volume between the chips and possibly even seal it off acoustically, connecting both chips without the adaptation structure AS would no longer be possible.

(21) FIG. 2 shows a top view of the first chip, wherein one of the connecting structures VS is embodied as a bond frame BR, which is arranged on the edge of the first chip and comprises a closed volume between the chips.

(22) Further locally arranged connecting structures VS are arranged as support elements STS, to ensure the mechanical stability of the component, in particular the cavity, and optionally to establish electrical interconnections between the chips.

(23) An acoustic channel AC is guided through the body of the first chip and enables the entry of acoustic waves into the component.

(24) FIG. 3 shows an embodiment in which the acoustic channel through the body of the first chip is omitted and it is instead led through an opening in the bond frame BR.

(25) The risk of the closure of the acoustic channel by liquid materials used during the production of the component or during the connection of the component to an external circuit environment is therefore reduced.

(26) FIG. 4 shows the corresponding view of the second chip, wherein support structures STS are neither arranged as the bond frame BR nor are provided to be interconnected with or connected to the frame-shaped connecting structure of FIG. 2. While connecting and contact structures can also have electrical functions in addition to the mechanical function, such structures are also usable as support structures without electrical function.

(27) FIG. 5 shows the view of the second chip associated with FIG. 3, wherein the contact structure is also embodied as a frame-shaped structure and has a sound entry opening in the form of an acoustic channel AC.

(28) FIG. 6 shows a first intermediate step during the production of a MEMS microphone, wherein contact pads KP for interconnection of the component with an external circuit environment are arranged on a lower side of the first chip CH1. An acoustic channel AC through the body of the first chip CH1 provides a sound entry opening SEO for sound waves. Through contacts through the chip, for example, to the contact pads on the lower side of the chip, are possible. They can be arranged adjacent to the channel independently of the acoustic channel. It is also possible that the channel AC itself carries metallic structures as through contact on its inner side.

(29) FIG. 7 shows a later intermediate step, in which local adaptation structures AS are arranged on the upper side of the first chip, to equalize height differences which are caused by MEMS structures on the lower side of the second chip.

(30) FIG. 8 shows a later intermediate step, wherein a first connecting structure VS1 in the form of a bond frame BR is arranged on the material of the adaptation structure AS. A second connecting structure VS2 is arranged in the form of a support stud PF on the upper side of the first chip, wherein no adaptation structure is arranged between the second connecting structure and the material of the first chip. A further connecting structure VS, for example, in the form of a support structure or a support stud, is arranged on the material of the adaptation structure.

(31) The connecting structures VS are essentially used to establish a connection to corresponding contact structures on the lower side of the second chip. The selective arrangement of the adaptation structure below the connecting structures enables the leveling of the two chips in spite of the connection of obstructing MEMS structures on the lower side of the second chip.

(32) FIG. 9 shows metallizations MET arranged on the connecting structures, so that an electrical interconnection can also be established via the mechanical connection of the connecting structure, for example, if the material of the connecting structures VS has little or no electrical conductivity. The metallizations can be interconnected with conductive structures, for example, signal lines, on the surface of the first chip or with through contacts through the first chip.

(33) FIG. 10 shows a further method step, wherein different heights of corresponding first and second contact structures KS1, KS2 are given by way of MEMS structures on the lower side of the second chip CH2. In the case of MEMS microphones, the different heights of the contact structures are primarily caused by structuring steps of membranes M and back plates BP. A solder material L is furthermore arranged on the metallizations on the connecting structures of the first chip CH1, to enable a soldered bond of the two chips.

(34) Furthermore, a back volume covered by a rear panel RSV is arranged in the second chip as the back volume of the MEMS microphone.

(35) FIG. 11 shows a further intermediate product, wherein a soldered bond connects and interconnects the two chips or the contact and connecting structures thereof.

(36) For the sake of simplicity, only individual components are always shown, which can be provided, however, in multiple panels in a plurality as elements of the corresponding wafers. FIG. 11 shows how individual second chips CH2 were separated from one another by first partial isolation steps, for example, by sawing.

(37) The first partial isolation step penetrates through the material of the second chip and into the material of the connecting structures VS.

(38) FIG. 12 illustrates how the first partial isolation steps PVS1 are carried out multiple times at wafer level and separate the individual second chips from one another.

(39) FIG. 13 shows a further intermediate product, wherein an insulating material IS was applied to the rear side of the rear panel and to the lateral surfaces of the second chips.

(40) FIG. 14 shows a further intermediate product, wherein an electrically conductive shield layer AS was applied to the insulating layer IS. The shield layer AS is insulated from the body of the second chip CH2 by the insulating layer IS.

(41) FIG. 15 shows a further intermediate product after a second partial isolation step PVS2, wherein the material of the first chip has been penetrated and the second partial isolation step PVS2 penetrates at least partially into the material of the connecting structure VS.

(42) FIG. 16 shows the final product, wherein a material of a further shield layer AS is arranged on the isolation edges of the first chip or the adaptation structure and the connecting structure. The material of the lower adaptation layer touches the material of the upper adaptation layer, so that a continuous electromagnetic shield is obtained. At the same time, the body of the first chip is electrically insulated by the insulation layer IS from the body of the second chip.

(43) If there is no necessity of insulating the body of the first chip from the body of the second chip, a single complete isolation step and a single deposition step are thus sufficient to apply the electromagnetic shield layer AS to the lateral surfaces and the rear side of the component.

(44) The support and contact structures can be interconnected, for example, via through contacts DK with the contact pads KP on the lower side of the first chip CH1. A simple but effective possibility is thus provided for interconnecting the internal interconnection of the component with an external circuit environment.

(45) The component and the production method are not restricted to the described exemplary embodiments and schematic illustrations. Combinations of individual features and variations which comprise, for example, still further coatings, layers, connecting or adaptation structures, or contact structures, also represent exemplary embodiments.