METHOD TO PRODUCE A RUGGEDIZED PACKAGE OF AN IMAGE SENSOR

Abstract

A method to produce a ruggedized package (1) of an image sensor comprises a step of producing a plurality of image sensors (100a, . . . , 100n), a step (S3, S4) of providing a supporting substrate (10) and placing the plurality of the image sensors (100a, . . . , 100n) on the supporting substrate (10) such that the image sensors (100a, . . . , 100n) are located spaced apart from each other on the supporting substrate (10), a step (S5) of filling a spacing (20) between the image sensors (100a, . . . , 100n) on the supporting substrate (10) with a molding material (200), a step (S6) of delaminating the arrangement of the plurality of the image sensors (100a, . . . , 100n) from the supporting substrate (10), and a step (S7) of singularizing the arrangement of the plurality of the image sensors (100a, . . . , 100n) such that each image sensor (100a, . . . , 100n) is surrounded by the molding material (200).

Claims

1. A method to produce a ruggedized package of an image sensor, comprising: producing a plurality of image sensors, placing the plurality of the image sensors on a supporting substrate such that the image sensors are located spaced apart from each other on the supporting substrate, filling a spacing between the image sensors on the supporting substrate with a molding material, delaminating the arrangement of the plurality of the image sensors being surrounded by the molding material from the supporting substrate, singularizing the arrangement of the plurality of the image sensors such that each image sensor is surrounded by the molding material.

2. The method of claim 1, wherein each of the image sensors comprises a bottom side comprising a plurality of external connections to externally contact the respective image sensor, a top side comprising a window element being transparent for ambient light, and lateral sides between the respective top and bottom side of the image sensors.

3. The method of claim 2, comprising: placing the image sensors on the supporting substrate such that the image sensors are placed with their respective top side on the supporting substrate.

4. The method of claim 3, comprising: filling the spacing between the image sensors with the molding material such that the lateral sides of each image sensor are embedded in the molding material.

5. The method of claims 3 or 4, comprising: filling the spacing between the image sensors with the molding material such that the respective bottom side of the image sensors is not covered by the molding material.

6. The method of claims 3 or 4, comprising: filling the spacing between the image sensors with the molding material such that the respective bottom side of the image sensors is covered by the molding material except of the tips of the external connections on the respective bottom side of the image sensors that protrude out of the molding material.

7. The method of claim 2, comprising: placing the image sensors on the supporting substrate such that the image sensors are placed with their respective bottom side on the supporting substrate.

8. The method of claim 7, comprising: filling the spacing between the image sensors with the molding material such that the lateral sides of each image sensor are embedded in the molding material and the respective top side of the image sensors is not covered by the molding material.

9. The method of claims 1 to 4, comprising: using a film assisted molding technique for filling the spacing between the image sensors on the supporting substrate with the molding material.

10. The method of claims 1 to 4, comprising: providing a double side tape being laminated on a metal carrier as the supporting substrate.

11. A ruggedized package of an image sensor, comprising: a window element being transparent for ambient light, a light sensitive area to receive the light incident through the window element, a substrate including an integrated circuit to provide an electrical output signal at external connections of the image sensor in dependence on the incident light, a molding material, wherein the external connections are arranged on a bottom side of the substrate and the window element is arranged on a top side of the substrate, wherein the molding material is arranged such that at least the lateral sides of the image sensor between the top and the bottom side of the image sensor are embedded in the molding material.

12. The packaging of claim 11, wherein the bottom side of the image sensor is not covered by the molding material.

13. The packaging of claim 11, wherein the bottom side of the image sensor is covered by the molding material except of the tips of the external connections that protrude out of the molding material.

14. The packaging of claims 11 to 13, wherein the top side of the image sensor is not covered by the molding material.

15. The packaging of claims 11 to 13, comprising: a carrying element that is arranged on the substrate to carry the window element such that a cavity is provided between the window element and the light sensitive area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 illustrates method steps of a method to produce a ruggedized wafer-level package of an image sensor,

[0019] FIG. 2A shows a cross-sectional view of a fan-in wafer-level package of an image sensor;

[0020] FIG. 2B shows a perspective view of a fan-in wafer-level package of an image sensor;

[0021] FIG. 3A shows a perspective view of a ruggedized package of an image sensor from a top side; and

[0022] FIG. 3B shows a perspective view of a ruggedized package of an image sensor from a bottom side.

DETAILED DESCRIPTION

[0023] The proposed method to produce a ruggedized package of an image sensor as well as a ruggedized package of an image sensor will now be described in more detail hereinafter with reference to the accompanying drawings showing different embodiments of the manufacturing method and the ruggedized package of the image sensor. The manufacturing method and the ruggedized package of the image sensor may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the disclosure will fully convey the scope of the manufacturing method and the ruggedized package of the image sensor to those skilled in the art.

[0024] FIG. 1 shows different steps of an embodiment of a method to produce a ruggedized wafer-level package that combines parts of a fan-in wafer-level packaging technique with fan-out wafer-level packaging.

[0025] In a step S1 and a step S2 a plurality of image sensors 100a, . . . , 100n are produced by using the fan-in wafer-level packaging technology. An image sensor produced by the fan-in wafer-level packaging technique is shown in a cross-sectional view in FIG. 2A and in a perspective view from the bottom side in FIG. 2B.

[0026] In a first step S1 of the method to produce a ruggedized package of an image sensor, an image sensor wafer 2 is bonded to an optical wafer 3. The image sensor wafer 2 may be a silicon wafer. A plurality of image sensors without a window element is realized by the image sensor wafer 2. The optical wafer 3 can be a glass wafer that is used to realize the window element for each of the image sensors.

[0027] The components of the image sensor wafer 2 are explained in the following with reference to the embodiment of an image sensor shown in FIGS. 2A and 2B. The image sensor wafer 2 comprises a substrate 130 on which components of a plurality of the image sensors are arranged. Each image sensor comprises the substrate 130, a light-sensitive area 120 arranged on the substrate 130, and microlenses 160 arranged on the light-sensitive area 120 as well as a damming material forming a cavity wall/carrying element 150 around the respective light-sensitive area 120 of the image sensors.

[0028] The substrate 130 comprises for each of the image sensor a respective integrated circuit to process the optical signals received by the respective light-sensitive area 120 of the light sensor, for example to transform an optical signal received by the light-sensitive area 120 in an electrical output signal. The light sensitive area 120 is configured as the image sensor/pixel area of the image sensor. Microlenses 160 are arranged above the light-sensitive area 120 to provide a focal plane to focus incident light onto the underlying light-sensitive area 120. In order to provide a cavity between the image sensor wafer 2 and the glass wafer 3, a damming material forming a cavity wall is dispensed around the light-sensitive area 120 of each of the plurality of image sensors.

[0029] In the method step S1, the glass wafer 3 that is used to provide a respective window element 110 at a distance above the substrate 130 for each of the plurality of image sensors is bonded to the image sensor wafer 2. As illustrated in the cross-sectional view of a manufactured fan-in wafer-level packaging of FIG. 2A, the glass wafer 3 is placed on the damming material that forms the carrying element 150 to carry the glass wafer at a distance above the image sensor wafer 2.

[0030] In the method step S1, the image sensor wafer 2 is then thinned down and via holes, for example, Through-Silicon Vias (TSVs), are provided in the substrate 130 to provide an electrical path to the back side of the image sensor wafer 2. According to another possible embodiment, external electricals connections to the back side of the image sensor wafer 2 can be provided through side contacts, such as shown in the embodiment of the fan-in wafer-level package of FIGS. 2A and 2B. External connections 140 are provided on the bottom side of the image sensor wafer to electrically contact the image sensor. Through redistribution and bumping a BGA package of an image sensor, as shown in FIGS. 2A and 2B, is made at the end of method step S1.

[0031] In the method step S2 the chip-scale packages that are provided at the end of method step S1 on wafer-level basis are singularized to produce the plurality of the image sensors 100a, . . . , 100n.

[0032] FIGS. 2A and 2B show one of these image sensors 100 produced by the fan-in wafer-level packaging technique. After being singularized in the method step S2, each package of an image sensor comprises the substrate 130 and a light-sensitive area, i.e. the image sensor/pixel area, 120 that is arranged on top of the substrate 130. The light-sensitive area 120 is configured to receive light incident through the window element 110 that is arranged spaced apart above the substrate 130. The microlenses 160 are arranged above the light-sensitive area 120. The window element 110 is transparent for ambient light so that the ambient light impinges through the window element 110 to the microlenses 160 which focus the incident light on the light-sensitive area 120.

[0033] FIG. 2A shows the carrying element 150 provided by the damming material that is deposited around the light-sensitive area 120. The carrying element 150 is arranged on the substrate 130 to carry the window element 110 such that a cavity 101 is provided between the window element 110 and the light-sensitive area 120/the microlenses 160. The cavity is configured as an air gap between the window element 110 and the substrate 130 with the light-sensitive area 120 and the microlenses arranged thereon.

[0034] FIGS. 2A and 2B show the external connections 140 that are arranged on a bottom side B100 of the image sensor 100 that is the bottom side of the substrate 130. The window element 110 is arranged on a top side of the substrate 130. According to the embodiment of the fan-in wafer-level package of the image sensor 100 shown in FIGS. 2A and 2B, the external connections 140 may be realized as solder bumps. A silicon encapsulant 170 is arranged in direct contact around the bottom side and the lateral sides around the substrate 130. A lead 180 to provide an electrical contact between the external connections on the bottom side of the substrate 130 and the integrated circuit 131 is embodied as a side contact to connect the integrated circuit 131 with the external connections 140. The lead 180 is covered by a lead encapsulant 190. FIG. 2B shows the external connections 140 being arranged on the bottom side B100 of the image sensor 100.

[0035] In the method step S3, a supporting substrate 10, on which the singularized image sensors 100 are to be placed, is provided. The supporting substrate 10 may comprise a metal carrier 11 being laminated by a double-sided tape 12. The top and the bottom side of the double-sided tape 12 may be provided with an adhesive so that the tape 12 adheres to the metal carrier 11. The supporting substrate 10 is shown in the illustration of the step S3 of FIG. 1 having a rectangular shape. It should be noted that the supporting substrate have any suitable other shape, for example a round shape.

[0036] In the method step S4 the plurality of the image sensors 100a, . . . , 100n are placed on the supporting substrate 10 such that the image sensors 100a, . . . , 100n are located spaced apart from each other on the supporting substrate 10. The image sensors 100a, . . . , 100n are arranged on the supporting substrate 10 so that a spacing/gap 20 is arranged between each individual image sensor 100a, . . . , 100n. The singularized individual image sensors 100a, . . . , 100n may be arranged on an adhesive surface of the tape 12 of the supporting substrate 10 by means of a pick-and-place procedure.

[0037] According to a possible embodiment of the method to produce the ruggedized package of an image sensor, the image sensors 100a, . . . , 100n may be placed on the supporting substrate 10 with their respective top side T100, i.e. with the window element 110, directly arranged on the supporting substrate 10 (placement with window down). According to another possible embodiment of the method to produce the ruggedized package of the image sensors, the image sensors 100a, . . . , 100n are placed on the supporting substrate 10 with their respective bottom side B100 directly arranged on the supporting substrate 10. In this case the image sensors 100a, . . . , 100n are placed with external connections 140 directly arranged on the tape 12 of the supporting substrate 10 (placement with window up).

[0038] In a subsequent manufacturing step S5 the spacing/gap 20 between the individual image sensors 100a, . . . , 100n on the supporting substrate 10 are filled with a molding material 200. According to a possible embodiment of the method to produce the ruggedized package of the image sensor, the spacing/gap 20 between the image sensors 100a, . . . , 100n is filled with the molding material 200 such that the lateral sides L1, L2, L3 and L4, shown in FIG. 2B, of each image sensor 100a, . . . , 100n are embedded in the molding material 200. That means that each lateral side L1, . . . , L4 of each image sensor 100a, . . . , 100n is completely surrounded and sealed by the molding material 200.

[0039] According to a possible embodiment of the manufacturing method, the spacing/gap 20 between the image sensors 100a, . . . , 100n on the supporting substrate 10 is filled with the molding material 200 such that the bottom side B100 of the image sensors 100a, . . . , 100n is not covered by the molding material 200, when the image sensors are placed in the window-down-configuration on the supporting substrate 10. The bottom side B100 of a singularized image sensor is shown in FIG. 2B. That means that the respective external connections 140 on the bottom side B100 of the image sensors are not covered by the molding material 200.

[0040] According to another embodiment of the method to produce a ruggedized package of an image sensor, the spacing/gap 20 between the image sensors 100a, . . . , 100n on the supporting substrate 10 is filled with the molding material 200 such that the bottom side B100 of the image sensors 100a, . . . , 100n is covered by the molding material 200 except for the tips of the external connections 140. That means that only the tips of the external connections 140 protrude out of the molding material 200 for providing an external connection of the image sensor.

[0041] In the case that the image sensors 100a, . . . , 100n are placed on the supporting substrate 10 in the window up-configuration, the spacing/gap 20 between the image sensors 100a, . . . , 100n may be filled with the molding material 200 such that the lateral sides L1, . . . , L4 of each image sensor 100a, . . . , 100n are embedded in the molding material 200 and the respective top side T100 of the image sensors 100a, . . . , 100n is not covered by the molding material 200. That means that each lateral side L1, . . . , L4 of the image sensors is completely surrounded by the molding material, and the top side T100, i.e. the window element 110, is free from the molding material 200.

[0042] The method step S5 can be performed by using a film-assisted molding technique that is similar to a fan-out wafer-level packaging technique. As illustrated in the method step S5, a molding tool 30 is provided and a film 40 are provided. The film 40 may be pressed against a structured surface of the molding tool 30 by means of a vacuum. The structured surface of the molding tool 30 comprises cavities and protrusions that are formed so that the film 40 allows that certain regions of the image sensors 100a, . . . , 100n are filled by the molding material 200 and other regions are protected from being covered by the molding material 200.

[0043] The structured surface of the molding tool 30 may be shaped such that the complete bottom surface B100 of each of the image sensors 100a, . . . , 100n is not covered by the molding material or that at least the tips of the external connections 140 on the bottom surface B100 are not covered by the molding material 200. The structured surface of the molding tool 30 is in each case shaped such that the spacing/gap 20 between the individual image sensors 100a, . . . , 100n are completely filled with the molding material 200. When the image sensors 100a, . . . , 100n arranged on the supporting substrate 10 in the window-up-configuration, the molding tool 30 may be structured such that the film 40 allows that only the spacing/gap 20 is filled with the molding material 200 and the top side T100 of the image sensors is not covered by the molding material.

[0044] In a method step S6, the arrangement of the plurality of the image sensors 100a, . . . , 100n being surrounded by the molding material 200 are delaminated from the supporting substrate 10. In a method step S7, the arrangement of the plurality of the image sensors 100a, . . . , 100n being surrounded by the molding material 200 is singularized. The arrangement of the plurality of the image sensors 100a, . . . , 100n being held together by means of the molding material 200 can be diced along the dicing lines DL illustrated in step 7 of FIG. 2. After the singulation, a package of an image sensor is produced, wherein at least the lateral sides L1, . . . , L4 of each image sensor 100a, . . . , 100n are surrounded by the molding material 200.

[0045] The manufactured ruggedized package 1 of an image sensor 100 after the singulation step S7 is shown from a top side in FIG. 3A and from a bottom side in FIG. 3B. The ruggedized package of the image sensor 1 comprises the fan-in wafer-level package of the image sensor 100 that is enframed by the molding material 200.

[0046] As shown in FIGS. 3A and 3B, the lateral sides L1, L2, L3 and L4 of the image sensor 100 are completely embedded in the molding material 200, whereas the top surface T100, i.e. the window element 110 and the bottom surface B100 including the external connections 140 are not covered by the molding material and thus are free from the molding material 200. The proposed method provides a ruggedized image sensor package having an improved resistance regarding moisture penetration. The molding material 200 provides a sealing around the fan-in wafer-level package of the image sensor 100 and protects the image sensor 100 from the penetration of moisture in the cavity 101 between the substrate 130 and the window element 110.