HK1220288B - Sensor package with exposed sensor array and method of making same - Google Patents

Description

Sensor package with exposed sensor array and method of manufacturing the same

Related applications

This application claims priority to U.S. Provisional Application No. 61/830,563, filed June 3, 2013, and U.S. Provisional Application No. 61/831,397, filed June 5, 2013, which are incorporated herein by reference.

Technical Field

The present invention relates to packaging of microelectronic sensor devices such as image sensors and chemical sensors, and more particularly to sensor packaging that leaves the sensor protected, electrically connected, yet exposed.

Background Art

The trend in semiconductor devices is toward smaller integrated circuit (IC) devices (also referred to as chips) packaged in smaller packages that protect the chip while providing off-chip signaling connectivity. An example is an image sensor, which is an IC device that includes a photodetector that converts incident light into an electrical signal.

Image sensors are typically encapsulated in a package that protects the sensor from contaminants and provides off-chip signaling connectivity. However, one issue is that the transparent substrate used to encapsulate the optical sensor can adversely affect the light that passes through it and reaches the sensor (e.g., distortion and photon loss). Another type of sensor is a chemical sensor, which detects physical substances such as gases and chemicals. However, chemical sensors cannot be sealed from the environment for operation, but it is still desirable to encapsulate such sensors for protection and off-chip signaling connectivity.

Conventional sensor packages are disclosed in U.S. Patent Publications 2005/0104186 and 2005/0051859, as well as U.S. Patent 6,627,864. Each of these disclosed sensor packages includes a sensor chip, a host substrate such as a silicon component, a PCB or flexible PCB, a window opening for the sensor area, and transparent glass that hermetically seals the sensor area. Optionally, and frequently, the sealing area is filled with a transparent epoxy to improve the bond strength between the sensor die and the host substrate, at the expense of at least some photon sensor sensitivity. The transparent glass protects the sensor area from contamination and moisture while also providing additional substrate strength and rigidity to the package. The sensor chip is typically mounted to the host substrate using flip-chip or wire bonding techniques. This allows the sensor bond pads to be connected to multiple metal traces on the surface of the host substrate via interconnects such as ball grid arrays (BGAs). The metal traces are typically deposited on the surface of the host substrate and typically consist of a single layer of circuitry. However, achieving reduced size with these configurations and preventing contamination of the sensor area during assembly are difficult.

There is a need for improved packaging and packaging techniques that provide some protection to the sensor with off-chip signaling connectivity while exposing the sensor to the conditions being detected. There is also a need for improved attachment and connectivity schemes with a supporting host substrate.

Summary of the Invention

The aforementioned problems and needs are solved by a packaged sensor assembly, which includes a first substrate having first and second opposing surfaces and a plurality of conductive elements each extending between the first and second surfaces. The second substrate includes opposing front and rear surfaces, one or more detectors formed on or in the front surface, and a plurality of contact pads formed at the front surface that are electrically coupled to the one or more detectors. A third substrate is mounted to the front surface to define a chamber between the third substrate and the front surface, wherein the third substrate includes a first opening extending from the chamber through the third substrate. The rear surface is mounted to the first surface. A plurality of wirings each extend between one of the contact pads and one of the conductive elements and electrically connect the two.

The packaged sensor assembly includes: a first substrate including opposing front and back surfaces; one or more detectors formed on or in the front surface; a plurality of contact pads formed at the front surface that are electrically coupled to the one or more detectors; a second substrate mounted to the front surface to define a chamber between the second substrate and the front surface, wherein the second substrate includes a first opening extending through the second substrate from the chamber; a groove formed into the front surface of the first substrate; and a plurality of conductive traces each extending from one of the contact pads and into the groove.

A method for forming a packaged sensor assembly includes providing a first substrate having opposing first and second surfaces; forming a plurality of conductive elements each extending between the first and second surfaces; providing a second substrate including opposing front and rear surfaces, one or more detectors formed on or in the front surface, and a plurality of contact pads formed at the front surface that are electrically coupled to the one or more detectors; mounting a third substrate to the front surface to define a chamber between the third substrate and the front surface, wherein the third substrate includes a first opening extending through the third substrate from the chamber; mounting the rear surface to the first surface; and providing a plurality of wirings each extending between one of the contact pads and one of the conductive elements and electrically connecting the two.

A method of forming a packaged sensor assembly includes providing a first substrate including opposing front and back surfaces, one or more detectors formed on or in the front surface, and a plurality of contact pads formed at the front surface that are electrically coupled to the one or more detectors; mounting a second substrate to the front surface to define a chamber between the second substrate and the front surface, wherein the second substrate includes a first opening extending through the second substrate from the chamber; forming a trench into the front surface of the first substrate; and forming a plurality of conductive traces each extending from one of the contact pads and into the trench.

Other objects and features of the present invention will become apparent from a review of the specification, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

1A-1P are cross-sectional side views sequentially illustrating steps in forming a packaged sensor assembly for an image sensor.

2 is a cross-sectional side view showing the lens module mounted to a packaged sensor assembly.

3 is a cross-sectional side view illustrating an alternative embodiment of a packaged sensor assembly for a chemical sensor.

4A-4F are cross-sectional side views sequentially illustrating steps in an alternative embodiment of forming a packaged sensor assembly.

5A-5B are cross-sectional side views illustrating a plurality of openings in a protective substrate for providing flow of a physical substance across a sensor.

6 is a cross-sectional side view showing a barrier structure in a chamber and multiple openings in a protective substrate for providing non-linear flow of a physical substance across a sensor.

DETAILED DESCRIPTION

The present invention is a packaging solution that provides protection to the sensor chip, provides off-chip signaling connectivity, has a minimal size, and can be reliably manufactured.

Figures 1A-1P illustrate the formation of a packaged sensor assembly 1. This formation begins with a wafer 10 (substrate) containing multiple sensors 12 formed thereon, as shown in Figure 1A. For illustrative purposes, the formation of the packaged sensor will be described with respect to optical sensors, but any sensor (e.g., chemical sensors, etc.) can be used. Each image sensor 12 includes multiple photodetectors 14, supporting circuitry 16, and contact pads 18. Sensors 12 are configured to detect and measure light incident on an active area 17 of each sensor 12. Contact pads 18 are electrically connected to the photodetectors 14 and/or their supporting circuitry 16 for providing off-chip signaling. Each photodetector 14 converts light energy into a voltage signal. Additional circuitry may be included to amplify the voltage and/or convert it into digital data. Color filters and/or microlenses 20 may be mounted above the photodetectors 14. Sensors of this type are well known in the art and are not further described herein.

Next, a protective substrate is formed with a sensor window opening. The protective substrate 22 can be glass or any other optically transparent or translucent rigid substrate. Glass is the preferred material. Glass with a thickness in the range of 50-1500 μm is preferred. The sensor area window opening 24 is formed in the protective substrate 22, for example, by laser, sandblasting, etching, or any other suitable cavity formation method. The opening 24 formed in the protective substrate 22 is illustrated in Figure 1B. The sidewalls of the opening 24 can be vertical as shown, or can taper inwardly or outwardly. Preferably, the openings 24 are equal to or smaller in size than the underlying active area 17 on which they will be placed, as illustrated in Figures 1D and 1F, respectively. Alternatively, there can be multiple openings 24 for each active area 17, as illustrated in Figures 1C and 1E. Each active area will have at least one opening 24. The openings 24 can be any shape or size compatible with the particular sensor functionality. The opening 24 will benefit the image sensor by eliminating the distortion and photon loss caused by the optically transparent protective substrate found in traditional image sensor packages. The opening 24 can also expose the sensor active area 17 to the environment, thereby allowing the chemical sensor detector to detect physical substances such as gases and chemicals to which the sensor is exposed.

An optional layer of spacer material 26 is deposited on protective substrate 22, either before or after forming openings 24. Spacer material 26 can be a polymer, an epoxy, and/or any other suitable material(s). Deposition can be achieved by roller printing, spraying, screen printing, or any other suitable method(s). The thickness of the deposited material can be in the range of 5-500 μm. Spacer material 26 can be aligned to the edge of opening 24 as shown in FIG. 1G , spaced from the edge of opening 24 as shown in FIG. 1H , or a combination of the two as shown in FIG. 1I . Preferably, spacer material 26 is positioned to avoid contact with active area 17 and contact pads 18 of substrate 10 (on which spacer material 26 is mounted) (e.g., it can be positioned between active area 17 and its corresponding contact pad 18).

The protective structure (substrate 22 and spacer material 26) is bonded to the active side of substrate 10 using a bonding agent. The bonding agent can be an epoxy deposited by roller printing and then thermally cured, or any other suitable bonding method known in the art. A protective tape 28 is placed over protective substrate 22, forming a hermetically sealed chamber 30 for each image sensor 12. The height of chamber 30 is preferably in the range of 5-500 μm. Chamber 30 can be filled with a gas, a liquid, or evacuated by creating a vacuum. Substrate 10 can optionally be thinned by removing material from its backside. In the case of a silicon substrate 10, silicon thinning can be accomplished by mechanical grinding, chemical mechanical polishing (CMP), wet etching, atmospheric downstream plasma (ADP), dry chemical etching (DCE), a combination of the aforementioned processes, or any other suitable silicon thinning method(s). The thickness of the thinned substrate 10 is in the range of 100-2000 μm. The resulting structure is shown in FIG1J.

The portion of the protective substrate 22 between the sensors 12 and above the contact pads 18 can be removed using laser cutting equipment, mechanical sawing, a combination of the aforementioned processes, or any other suitable glass cutting method(s). Laser cutting is the preferred cutting method. This process separates each protective chamber 30 from other protective chambers for other sensors 12, thereby achieving protection chamber singulation. This step also exposes the sensor pads 18. The substrate 10 is then singulated/diced to separate each sensor 12 and its corresponding package. Wafer-level dicing/singling can be accomplished using mechanical blade dicing equipment, laser cutting, or any other suitable process. The resulting structure is shown in FIG1K .

The main substrate assembly 34 is formed by first providing a main substrate 36, which can be an organic flexible PCB, an FR4 PCB, silicon (rigid), glass, ceramic, or any other type of packaging substrate. VIA (vertical interconnect access) openings 38 can be made through the main substrate 36 via mechanical drilling, laser, dry etching, wet etching, or any other suitable VIA opening formation method known in the art. Preferably, a laser is used to form the VIA openings 38. The VIA opening walls can be tapered to form a funnel shape, or the top and bottom of the VIA can have the same dimensions to form a cylindrical shape. The resulting structure is shown in FIG1L .

A dielectric material layer 40 is formed over all surfaces of the main substrate 36, including the sidewalls of the VIA openings 38. Layer 40 is desirable if the main substrate 36 is made of a conductive material, such as conductive silicon. Dielectric material layer 40 may be silicon dioxide deposited by physical vapor deposition (PVD). If the main substrate 36 is made of a non-conductive organic material, such as a flexible PCB or FR4 resin, dielectric layer 40 may be omitted. Conductive material 42 is then formed over all surfaces of the main substrate 36, including partially or completely filling the VIA openings 38. Conductive material 42 may be copper, aluminum, a conductive polymer, or any other suitable conductive material(s). Conductive material 42 may be deposited by physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplating, or any other suitable deposition method(s). The sidewalls of the VIA openings 38 may be coated with conductive material 42, or the VIA openings 38 may be completely filled with conductive material 42, as shown in FIG. 1M .

A photoresist layer 44 is deposited on both the top and bottom surfaces of the main substrate 36. The photoresist deposition method can be spray coating or any other suitable deposition method(s). The photoresist 44 is exposed and etched using a suitable photolithography process known in the art, leaving photoresist 44 only above the paths and VIA openings 38 that will eventually form the traces. A conductive material etch is performed to remove the exposed portions of the conductive layer 42 (i.e., those portions not underneath the remaining photoresist 44). For example, leads, contacts, rerouting contacts, and traces can be formed by this etching, which can use dry or wet etching methods known in the art. The resulting structure is shown in FIG1N.

The photoresist is stripped using sulfuric acid, acetone, or any other suitable photoresist stripping method. An optional electroplating process (e.g., Ni/Pd/Au) may be performed on the conductive material 42. Interconnects 46 are formed on the conductive material 42 above the VIA openings 38 on the bottom side of the main substrate 36. The interconnects may be ball grid arrays (BGAs), land grid arrays (LGAs), bumps, copper pillars, or any other suitable interconnect method. BGAs are a preferred interconnect method and can be deposited by screen printing followed by a reflow process. The singulated substrates 10 (with sensors 12) described above are then attached to the main substrate using a suitable adhesive 48, for example, by depositing the adhesive on the substrate 10, the main substrate 36, or both, and picking up/placing the substrate 10 onto the main substrate 36, followed by a suitable curing process. Electrical interconnects are added between the contact pads 18 and the conductive material 42 in the VIA openings 38, preferably bond wires 50 as is known in the art. The resulting structure is shown in FIG10 .

An overmold material 52 is dispensed over the primary substrate 36 and the mounted sensors 12 therebetween. The overmold material 52 may be an epoxy, a resin, or any other overmold material(s) known in the art. The upper surface of the cured overmold material 52 is preferably lower than the upper surface of the protective substrate 22 and higher than the upper surface of the wiring bond contacts. The primary substrate 36 is then singulated along the scribe lines between the mounted sensors 12. The dicing/singling of the package may be accomplished using mechanical blade dicing equipment, laser cutting, or any other suitable process. The final sensor package is mounted to a second primary substrate 54 via interconnects 46. The second primary substrate 54 may be a flexible PCB, a rigid PCB, or any other suitable structure having contact pads and electrical interconnects. The protective tape 28 is then removed, thereby exposing the active area 17 of the sensor 12 to the environment. The final packaged sensor assembly 1 is shown in FIG. 1P .

In the final structure, sensor 12 is protected by a protective substrate that extends only partially over substrate 10, leaving sensor 12 exposed to the environment. In particular, light incident on the structure can pass directly to sensor 12 without passing through any transparent protective substrate. Conductive material 42 in VIA opening 38 forms a through-contact electrical contact or conductive element that passes through substrate 36 and extends between wiring 50 and interconnect 46. Overmold material 52 protects the wiring 50 connection.

Figure 2 illustrates a lens module 60 that may be mounted to the structure of Figure IP. The lens module 60 includes a housing 62 in which one or more lenses 64 are mounted to focus incoming light onto the image sensor 12 without having to pass through any protective substrate.

3 illustrates a packaged sensor assembly 1 having a chemical sensor 70 instead of an image sensor 12. The chemical sensor 70 includes one or more chemical detectors 72 formed in or on the substrate 10 for detecting the presence of certain chemicals or particles that enter the chamber 30 through the opening 24. The chemical detectors 72 generate signals in response to the detected chemicals or particles and provide those signals to the contact pads 18. Chemical sensors of this type are well known in the art and are not described further herein.

Figures 4A-4F illustrate the formation of an alternative embodiment of a packaged sensor assembly. This formation begins with the structure shown in Figure 1K, but before dicing/singulation. A photoresist layer 44 is deposited over the structure. Photoresist deposition can be achieved by spray coating or any other suitable deposition method(s). Photoresist 74 is exposed and selectively etched using a suitable photolithography process known in the art. Cured/hardened photoresist 74 exposes portions of the substrate between sensors 12. The exposed portions of substrate 10 are etched (e.g., by anisotropic dry etching) to form trenches in the top surface of substrate 10. Etches such as CF4, SF6, NF3, Cl2, CCl2F2, or any other suitable etchant can be used. The preferred depth of trench 76 is in the range of 5% to 50% of the thickness of substrate 10. The resulting structure is shown in Figure 4A.

Photoresist 74 is stripped using acetone or any other dry plasma or wet photoresist stripping method known in the art. A passivation layer 78 of an insulating material, such as silicon dioxide or silicon nitride, is deposited over the structure. Preferably, passivation layer 78 is made of silicon dioxide and is at least 0.5 μm thick. Silicon dioxide deposition can be performed using physical vapor deposition (PVD), PECVD, or any other deposition method(s). A photoresist layer 80 is deposited over passivation layer 78. Photoresist 80 is exposed and selectively etched using a suitable photolithography process known in the art to remove those portions of the photoresist above contact pads 18 and along and above spacer material 26, protective substrate 22, and strap 28 (thereby exposing portions of passivation layer 78 above these areas). The exposed portions of passivation layer 78 are removed, for example, by plasma etching, to expose contact pads 18, spacer material 26, protective substrate 22, and strap 28. If the passivation layer 78 is silicon dioxide, then etchants CF4, SF6, NF3, or any other suitable etchant may be used. If the passivation layer 78 is silicon nitride, then etchants CF4, SF6, NF3, CHF3, or any other suitable etchant may be used. The resulting structure is shown in FIG4B .

After removing photoresist 80, a conductive material 82 is deposited over the structure. Conductive material 82 can be copper, aluminum, a conductive polymer, or any other suitable conductive material(s). The conductive material can be deposited by physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplating, or any other suitable deposition method(s). Preferably, conductive material 82 is aluminum and is deposited by PVD. A photoresist layer 84 is deposited over the structure. Photoresist 84 is exposed and etched using a suitable photolithography process to form a mask over conductive layer 82 over contact pads 18 and in trenches 76. Photoresist 84 is removed over strips 28, protective layer 22, spacer material 26, and optionally where substrate 10 will be cut in trenches 76, thereby optionally exposing conductive layer 82 in those areas. The exposed portions of conductive layer 82 are removed, for example, using a dry or wet etching process. The remaining portions of conductive layer 82 form a plurality of discrete traces (leads), each extending from one of contact pads 18 down to the bottom of one of trenches 76. The etchant used for wet etching can be phosphoric acid (H3PO4), acetic acid, nitric acid (HNO3), or any other suitable etchant(s). The etchant used for dry etching can be Cl2, CCl4, SiCl4, BCl3, or any other suitable etchant(s). Dry etching is the preferred method for forming the lead. Optionally, conductive material 82 can remain on the sidewalls of the protective substrate. The resulting structure is shown in FIG4C .

The remaining photoresist 84 is then removed. Optionally, an electroplating process (e.g., Ni/Pd/Au) can be performed on the leads (conductive layer 82). An optional encapsulant layer 86 is deposited over the conductive lead structures. Encapsulant layer 86 can be made of polyimide, ceramic, polymer, polymer composite, parylene, metal oxide, silicon dioxide, silicon nitride, epoxy, silicone, porcelain, nitride, glass, ionic crystal, resin, combinations of the foregoing, or any other suitable dielectric material(s). Encapsulant layer 86 is preferably 0.1 to 2 μm thick, and a preferred material is a liquid photolithographic polymer such as solder mask, which can be deposited by spray coating. A photolithography process is performed, in which the developed/cured encapsulant 84 is removed, except for that over the leads. Rerouting contacts 88 can be created by forming openings in encapsulant layer 86 at the bottom of trench 76. Optionally, encapsulant material can remain on the sidewalls of protective substrate 22 and/or on tape 28. The resulting structure is shown in FIG4D .

Wafer-level dicing/singulation of the components can be performed using mechanical blade dicing equipment, laser cutting, or any other suitable process, preferably at the bottom of trench 76. Interconnects 90 can be formed on rerouted contact pads or on a flexible PCB. Interconnects 90 can be BGAs, LGAs, stud bumps, plated bumps, adhesive bumps, polymer bumps, copper pillars, micro-rods, or any other suitable interconnect method(s). Preferably, interconnects 90 are made of adhesive bumps, which are a composite of conductive material(s) and adhesive material(s). The conductive material(s) can be solder, copper, silver, aluminum, gold, a combination of the aforementioned materials, or any other suitable conductive material(s). The adhesive material(s) can be varnish, resin, a combination of the aforementioned materials, or any other suitable adhesive material(s). The conductive adhesive can be deposited using an air-powered dispensing gun or any other suitable dispensing method(s) and then cured using heat, UV, or any other suitable curing method(s), thereby forming the bumps.

The flexible PCB can be mounted on all sides, three sides, two sides, or a single side of substrate 10. For example, two flexible PCBs 92 can be bonded to opposite sides of substrate 10. Alternatively, a single flexible PCB 92 with a window opening can be used, extending away from one, two, three, or all sides of substrate 10. Flexible PCB 92 can be any rigid or flexible substrate having one or more circuit layers 93 and contact pads 18a connected thereto. Interconnects 90 are electrically connected between contact pads 18a and conductive traces 82. The sensor package is placed within a pre-molded mold, and a selected overmold compound 94 is then injected into the mold. Overmold material 94 can be an epoxy, polymer, resin, or any other overmold material(s) known in the art. The top surface of the cured overmold material can be as high as the top surface of protective substrate 22, but preferably does not extend any higher. Cured overmold material 94 preferably does not extend beyond substrate 10. Protective tape 28 is then removed, exposing the sensor active area to the environment. The resulting structure is shown in Figure 4E.An optional lens module 60 as described above may be attached on top of the structure, as shown in Figure 4F.

The structure described above provides a more compact chip-on-film (COF) package than known packages. The thinner structure can be achieved by creating a stepped structure on the edge of substrate die 10, then forming multiple metal traces and rerouting contact pads on a second stepped surface that connects to top surface contact pads 18 via metal traces. A flexible cable and/or PCB is bonded to this second stepped surface. This structure reduces the height of protective substrate 22 by bonding it directly to sensor die 10 rather than mounting it on a host substrate, thereby reducing package thickness.

The structure described above also increases the sensitivity of the image sensor through the packaging structure. In particular, greater photon sensitivity can be achieved by simply not obstructing the light path. By creating openings 24 in the protective substrate 22 and not using any transparent underfills at the sensor area cavity, more photons can reach the active area with greater accuracy. Conventional devices rely on a protective substrate and transparent underfills to protect the sensor area by hermetically sealing it. However, the same hermetic seal can be achieved using the lens module 60. Finally, better structural integrity is achieved by enclosing the entire bonding area using overmold material 52/94 rather than simply applying a mold around the bonding surface as an adhesive/underfill.

For chemical sensor embodiments, multiple openings 24 can be used to facilitate the flow of physical species through chamber 30 and over the active area of the sensor. Input and output attachments 96 and 98 connect to openings 24 on protective substrate 22, whereby physical species such as gas or liquid flow through the packaged structure, as indicated by the arrows in Figures 5A and 5B. An optional barrier structure 100 can be included in chamber 30 to guide the physical species through the chamber in a nonlinear path, as shown in Figure 6.

It is to be understood that the present invention is not limited to the embodiment(s) described above and illustrated herein, but encompasses any and all variations that fall within the scope of the appended claims. For example, references herein to the invention are not intended to limit the scope of any claim or claim term, but instead merely reference one or more features that may be covered by one or more claims. The materials, processes, and numerical examples described above are merely exemplary and should not be construed as limiting the claims. Additionally, as will be apparent from the claims and description, all method steps need not be performed in the exact order illustrated or claimed, but rather in any order that allows for proper formation of the packaged sensor assembly 1. Finally, a single layer of material may be formed as multiple layers of such or similar material, and vice versa.

It should be noted that, as used herein, the terms “on” and “on” both non-exclusively include “directly on” (without intervening materials, elements, or spaces disposed therebetween) and “indirectly on” (with intervening materials, elements, or spaces disposed therebetween). Similarly, the term “mounted to” includes “directly mounted to” (without intervening materials, elements, or spaces disposed therebetween) and “indirectly mounted to” (with intervening materials, elements, or spaces disposed therebetween), and “electrically coupled to” includes “directly electrically coupled to” (without intervening materials or elements electrically connecting the elements together) and “indirectly electrically coupled to” (with intervening materials or elements electrically connecting the elements together). For example, forming an element “on a substrate” may include forming the element directly on the substrate without intervening materials/elements therebetween, as well as forming the element indirectly on the substrate with intervening materials/elements therebetween.

Claims (34)

1. A packaged sensor assembly, comprising: A first substrate has opposing first and second surfaces and a plurality of conductive elements extending between the first and second surfaces, respectively; a second substrate includes: The front and rear surfaces are opposite to each other. One or more detectors formed in or on the front surface. Multiple contact pads formed on the front surface are electrically coupled to one or more detectors. The third substrate is mounted to the front surface using a spacer material directly disposed on the third substrate and an epoxide bonding agent disposed between the spacer material and the front surface to define a cavity between the third substrate and the front surface, wherein the third substrate includes a first opening extending laterally from the cavity through the third substrate and entirely over the one or more detectors. The rear surface is mounted onto the first surface; Multiple wires, each extending between one of the contact pads and one of the conductive elements and electrically connecting one of the contact pads and one of the conductive elements; The outer mold material encapsulates the wiring, one or more portions of the first surface of the first substrate are adjacent to the conductive element, and one or more portions of the front surface of the second substrate are adjacent to the plurality of contact pads; A lens module is mounted to the outer mold material but not to the third substrate, wherein the lens module includes a housing and one or more lenses positioned to focus light through the first opening and to the one or more detectors. 2. The packaged sensor assembly of claim 1, wherein the first substrate is made of conductive silicon material, and wherein the assembly further comprises an insulating material disposed between the conductive element and the first substrate. 3. The packaged sensor assembly of claim 1, wherein one or more detectors comprise a plurality of photodetectors. 4. The encapsulated sensor assembly as claimed in claim 3, wherein the first opening is disposed on the plurality of photodetectors. 5. The packaged sensor assembly of claim 1, wherein one or more detectors include one or more chemical sensors. 6. The packaged sensor assembly as described in claim 5, further comprising: The second opening extends from the chamber through the third substrate. 7. The packaged sensor assembly as described in claim 6, further comprising: One or more barrier structures in a chamber that define a nonlinear flow path between a first opening and a second opening. 8. A packaged sensor assembly, comprising: A first substrate comprising opposing front and rear surfaces; One or more detectors formed in or on the front surface; Multiple contact pads formed on the front surface are electrically coupled to one or more detectors; A second substrate is mounted to a front surface to define a cavity between a second substrate and the front surface, wherein the second substrate includes a first opening extending from the cavity through the second substrate; A trench formed in the front surface of the first substrate and extending toward but not reaching the rear surface; and Each extends from one of the contact pads into multiple conductive traces in the trench; An insulating material that covers the upper surface of a plurality of conductive traces, except for the contact portion of the upper surface of the conductive traces in the trench; A third substrate having one or more circuit layers and a plurality of contact pads electrically coupled to the one or more circuit layers; and an electrical connector, each electrically connecting a contact portion of one of the conductive traces to one of the contact pads of the third substrate. 9. The packaged sensor assembly of claim 8, wherein the second substrate is mounted to the front surface by a spacer material disposed between the second substrate and the front surface. 10. The packaged sensor assembly of claim 8, wherein one or more detectors comprise a plurality of photodetectors. 11. The packaged sensor assembly of claim 10, wherein the first opening is disposed on the plurality of photodetectors. 12. The packaged sensor assembly of claim 8, wherein one or more detectors include one or more chemical sensors. 13. The packaged sensor assembly of claim 12, further comprising: The second opening extends from the chamber through the second substrate. 14. The packaged sensor assembly of claim 13, further comprising: One or more barrier structures in a chamber that define a nonlinear flow path between a first opening and a second opening. 15. The packaged sensor assembly as described in claim 8, further comprising: The outer mold material encapsulates at least part of the front surface, electrical connector, and third substrate. 16. The packaged sensor assembly of claim 15, further comprising: A lens module is mounted to an outer mold material, wherein the lens module includes a housing and one or more lenses positioned to focus light through a first opening and onto one or more detectors. 17. A method of forming a packaged sensor assembly, comprising: A first substrate having opposing first and second surfaces is provided; Multiple conductive elements are formed, each extending between the first and second surfaces; A second substrate is provided, the second substrate comprising: The front and rear surfaces are opposite to each other. One or more detectors formed in or on the front surface, and Multiple contact pads formed on the front surface are electrically coupled to one or more detectors; A first opening is formed through the third substrate; Spacer material is formed directly on the third substrate; The third substrate is mounted to the front surface using an epoxide bonding agent disposed directly between the spacer material and the front surface to define a cavity between the third substrate and the front surface, wherein the first opening extends from the cavity through the third substrate and extends laterally over the one or more detectors. Place the protective strip on the third substrate and above the first opening; Mount the rear surface onto the first surface; Provides a plurality of wirings, each extending between one of the contact pads and one of the conductive elements and electrically connecting the one of the contact pads and one of the conductive elements; and The protective tape is removed after the rear surface is mounted to the first surface and after the plurality of wirings are provided. 18. The method of claim 17, further comprising: The wiring is encapsulated using an outer mold material, one or more portions of the first surface of a first substrate adjacent to a conductive element, and one or more portions of the front surface of a second substrate adjacent to a plurality of contact pads. 19. The method of claim 17, wherein the first substrate is made of a conductive silicon material, the method further comprising: An insulating material is formed between the conductive element and the first substrate. 20. The method of claim 17, wherein one or more detectors comprise a plurality of photodetectors. 21. The method of claim 20, wherein the first opening is disposed on the plurality of photodetectors. 22. The method of claim 17, wherein one or more detectors comprise one or more chemical sensors. 23. The method of claim 22, further comprising: A second opening is formed, extending from the chamber through the third substrate. 24. The method of claim 23, further comprising: One or more barrier structures in a chamber that form a nonlinear flow path between a first opening and a second opening. 25. The method of claim 18, further comprising: The lens module is mounted to the outer mold material but not to the third substrate, wherein the lens module includes a housing and one or more lenses positioned to focus light through a first opening and onto one or more detectors. 26. A method of forming a packaged sensor assembly, comprising: A first substrate is provided, comprising: The front and rear surfaces are opposite to each other. One or more detectors formed in or on the front surface, and Multiple contact pads formed on the front surface are electrically coupled to one or more detectors; A second substrate is mounted to a front surface to define a cavity between the second substrate and the front surface, wherein the second substrate includes a first opening extending through the second substrate from the cavity. A trench is formed in the front surface of the first substrate and extends toward the rear surface but does not reach the rear surface; and Multiple conductive traces are formed, each extending from one of the contact pads into the trench; An insulating material that covers the upper surface of a plurality of conductive traces, except for the contact portion of the upper surface of the conductive traces in the trench; A third substrate is provided, having one or more circuit layers and a plurality of contact pads electrically coupled to the one or more circuit layers; and An electrical connector is formed, wherein one of the contact portions of one of the conductive traces is electrically connected to one of the contact pads of the third substrate. 27. The method of claim 26, wherein the second substrate is mounted to the front surface by means of a spacer material disposed between the second substrate and the front surface. 28. The method of claim 26, wherein one or more detectors comprise a plurality of photodetectors. 29. The method of claim 28, wherein the first opening is disposed on the plurality of photodetectors. 30. The method of claim 26, wherein one or more detectors comprise one or more chemical sensors. 31. The method of claim 30, further comprising: A second opening is formed that extends from the chamber through the second substrate. 32. The method of claim 31, further comprising: One or more barrier structures in a chamber that form a nonlinear flow path between a first opening and a second opening. 33. The method of claim 26, further comprising: At least part of the front surface, electrical connector, and third substrate are encapsulated in the outer mold material. 34. The method of claim 33, further comprising: The lens module is mounted onto the outer mold material, wherein the lens module includes a housing and one or more lenses positioned to focus light through a first opening and onto one or more detectors.