Module for optical device, and manufacturing method therefor

A module for an optical device being provided with a wiring substrate having a conductive wiring patterned thereon, a solid-state image sensor, a DSP for controlling the operation of the solid-state image sensor and processing a signal outputted from the same, and a lens holder being placed opposite to the solid-state image sensor and having a function of an optical path demarcating unit for demarcating the optical path to the solid-state image sensor, wherein a transparent cover bonded to the surface of the solid-state image sensor is joined to the lens holder at a joint portion. It is unnecessary to provide a focus adjuster for matching the optical distance between the lens and the solid-state image sensor with the focal length of the lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2003-092329 filed in Japan on Mar. 28, 2003, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a module for an optical device suitable for a camera module and the like for capturing an image of an object, and to a manufacturing method therefor.

2. Description of Related Art

A portable electronic apparatus such as a cellular phone or the like has recently been equipped with a camera function, so that a module for an optical device such as a camera module has been developed (for example, see Japanese Patent Application Laid-Open No. 2002-182270).

FIG. 1is a schematic view showing a section of a conventional module for an optical device. Reference numeral30denotes a wiring substrate30which has conductive wirings31patterned on its surface (both surfaces). The conductive wirings31formed on both surfaces of the wiring substrate30are appropriately connected to each other within the wiring substrate30. A DSP (Digital Signal Processor)32is die-bonded to one side (a surface on which a lens37described later is placed: this surface will be hereinafter referred to as an upper surface) of the wiring substrate30. Each connecting terminal of the DSP32is electrically connected to the conductive wiring31by a bonding wire32w. Bonded on the upper surface of the DSP32is a spacer33that is a sheet-shaped insulative adhesive. A solid-state image sensor34is die-bonded on the upper surface of the spacer33. Each connecting terminal of the solid-state image sensor34is electrically connected to the conductive wiring31by a bonding wire34w.

Reference numeral37denotes an objective lens which is held at the inner peripheral portion of a focus adjuster36. The focus adjuster36is provided at the inner peripheral portion close to the upper end portion of a lens holder main body35. The lens holder main body35is formed such that its lower end portion is widened rather than its upper end portion. The widened lower end portion of the lens holder main body35is bonded to the peripheral portion of the wiring substrate30. The focus adjuster36is threaded at its outer periphery, and the lens holder main body35is also threaded at its inner periphery close to its upper end portion. The threaded outer periphery of the focus adjuster36is screwed onto the threaded inner periphery close to the upper end portion of the lens holder main body35. Accordingly, it is configured such that pivotable rotation of the focus adjuster36changes the mutual position, i.e., the distance between the lens37and the solid-state image sensor34. It is noted that the lens holder main body35and the focus adjuster36form a lens holder for holding the lens37. Specifically, the lens37is positioned by the lens holder (lens holder main body35, focus adjuster36) with (the surface of) the wiring substrate30defined as a positioning reference. Bonded to the lens holder main body35is an optical filter38that is subject to filtering treatment for cutting infrared rays in incident ray.

There may be a case where the size (especially the size in the thickness direction) of the wiring substrate30has a warp, distortion or the like due to variations in production, even if it is within the range of the specification value. Even after the lens holder main body35is bonded, such warp or distortion is present on the wiring substrate30. Specifically, upon positioning the lens37, there may be the case where the optical distance between the lens37and the solid-state image sensor34does not agree with the focal length f of the lens37due to the warp or the like on (the surface of) the wiring substrate30that is a positioning reference. In this case, the optical distance between the lens37and the solid-state image sensor34is required to be adjusted so as to agree with the focal length f of the lens37. In other words, the optical distance between the lens37and the solid-state image sensor34is required to be adjusted so as to agree with the focal length f of the lens37by pivotably rotating the focus adjuster36. Accordingly, the module for an optical device is finally completed by adjusting the relative position of the focus adjuster36to the lens holder main body35.

FIG. 2throughFIG. 4are schematic views each showing a section for explaining a problem of a conventional module for an optical device.FIG. 2is a schematic view showing a case where the center portion of the wiring substrate30is formed into a convex shape toward the lens37. Although the parallel relationship between the lens37and the wiring substrate30is maintained, the peripheral portion of the wiring substrate30is warped toward the direction apart from the lens37, compared to its center portion. Therefore, the lens holder main body35whose widened lower end portion is bonded to the peripheral portion of the wiring substrate30is downwardly moved (in the direction apart from the lens37) with respect to the center portion of the wiring substrate30. This means that the positioning reference for the lens37is moved downward. Specifically, the optical distance between the lens37and the solid-state image sensor34becomes f−Δf (Δf is an amount of deformation of the wiring substrate30at the peripheral portion with respect to the center portion in the thickness direction), that is different from the focal length f of the lens37. Accordingly, it is required to agree the solid-state image sensor34with the position of the focal length f of the lens37by performing an adjustment corresponding to the deformation amount Δf with the focus adjuster36, i.e., by performing an adjustment for separating the solid-state image sensor34from the lens37, in the state shown inFIG. 2.

FIG. 3is a schematic view showing a case where the center portion of the wiring substrate30is formed into a concave shape toward the lens37. Although the parallel relationship between the lens37and the wiring substrate30is maintained, the peripheral portion of the wiring substrate30comes close to the lens37, compared to its center portion. Therefore, the lens holder main body35whose widened lower end portion is bonded to the peripheral portion of the wiring substrate30is upwardly moved (in the direction of coming close to the lens37) with respect to the center portion of the wiring substrate30. This means that the positioning reference for the lens37is moved upward. Specifically, the optical distance between the lens37and the solid-state image sensor34becomes f+Δf (Δf is an amount of deformation of the wiring substrate30at the peripheral portion with respect to the center portion in the thickness direction), that is different from the focal length f of the lens37. Accordingly, it is required to agree the solid-state image sensor34with the position of the focal length f of the lens37by performing an adjustment corresponding to the deformation amount Δf with the focus adjuster36, i.e., by performing an adjustment for making the solid-state image sensor34close to the lens37, in the state shown inFIG. 3.

FIG. 4is a schematic view showing a case where the plate thickness of the wiring substrate30is not uniform. In the example shown inFIG. 4, the thickness is great at the right-side end portion (right end in the figure) of the wiring substrate30, while the thickness is small at the left-side end portion (left end in the figure) thereof. Assuming that the plane shape of the wiring substrate30is a rectangular, each side having approximately 10 mm, and the difference of the thickness between at the opposing ends of the wiring substrate30is ±0.01 mm in case where the thickness of the wiring substrate30is different at the opposing ends. Even if the thickness itself of the wiring substrate30is within the specification, the lens holder main body35and the focus adjuster36are fixed so as to be inclined with respect to the surface (plane) of the solid-state image sensor34when the lens holder main body35is bonded to the wiring substrate30. When the lens holder main body35and the focus adjuster36are fixed so as to be inclined with respect to the surface of the solid-state image sensor34, a deviation of an angle θ occurs between the optical axis of the lens37and the vertical axis of the solid-state image sensor34, thereby incapable of correctly projecting an image of a subject onto the solid-state image sensor34.

As described above, in the conventional optical device module, (the surface of) the wiring substrate30is defined as the positioning reference for the lens and the lens holder (optical path demarcating unit, focus adjuster) is bonded to the wiring substrate30. Therefore, there may be the case where the optical distance between the lens37and the solid-state image sensor34does not agree with the focal length of the lens37due to variations in production such as warp or distortion on the wiring substrate30and, further, there is a problem that the optical axis of the lens37and the vertical axis of (the surface of) the solid-state image sensor34do not agree with each other. Therefore, an adjusting process is inevitable for matching the optical distance between the lens37and the solid-state image sensor34with the focal length of the lens37for each module for an optical device. In this adjusting process, an expensive system for the adjustment and a skilled worker are necessary and, further, a time required for the adjusting process is far from short. Moreover, the lens holder has to have a function of two mechanism elements of the optical path demarcating unit and the focus adjuster; therefore, it is difficult to achieve a small-sized lens holder in terms of its structure. Additionally, a mass-production is difficult since the lens holder is a mechanism element, whereby the percentage of the material cost in the production cost is high, thereby entailing an increased production cost.

BRIEF SUMMARY OF THE INVENTION

The invention is accomplished in view of the above-mentioned circumstances, and it is therefore an object of the invention to provide a small-sized and low cost module for an optical device that can be realized by that a focus adjuster for matching an optical distance between a lens and a solid-state image sensor with a focal length of the lens is not required. It is another object of the invention to provide a manufacturing method of a module for an optical device wherein a production process can be simplified since an adjusting process for matching an optical distance between a lens and a solid-state image sensor with a focal length of the lens is unnecessary.

According to the invention, a module for an optical device being provided with a solid-state image sensor having an effective pixel region formed on one side thereof and an optical path demarcating unit for demarcating an optical path from an objective lens to the effective pixel region, is characterized by comprising: a transparent cover placed opposite to the effective pixel region on the solid-state image sensor; a bonding portion for fixedly bonding the transparent cover to the solid-state image sensor; and a joint portion for fixedly joining the optical path demarcating unit to the transparent cover; whereby the objective lens is positioned with respect to the effective pixel region with the one side of the solid-state image sensor defined as a positioning reference, by fixedly joining the optical path demarcating unit to the transparent cover via the joint portion, and by fixedly bonding the transparent cover to the solid-state image sensor via the bonding portion.

A module for an optical device according to the invention is characterized in that the joint portion is joined by fixedly bonding the transparent cover and the optical path demarcating unit.

A module for an optical device according to the invention is characterized in that the transparent cover is formed to have a plane size smaller than the plane size of the one side of the solid-state image sensor.

A module for an optical device according to the invention is characterized in that the bonding portion contains a photosensitive bonding agent.

A module for an optical device according to the invention is characterized in that a space is formed between the effective pixel region and the transparent cover, and the bonding portion is formed at the peripheral portion of the effective pixel region on the one side of the solid-state image sensor.

A module for an optical device according to the invention is characterized in that the bonding portion is configured to seal the space formed between the effective pixel region and the transparent cover.

A module for an optical device according to the invention is characterized in that the lens is placed so as to oppose to the effective pixel region, and is held by the optical path demarcating unit.

A module for an optical device according to the invention is characterized in that an image processing device is bonded to a wiring substrate, and the solid-state image sensor is bonded to a plane portion of the image processing device.

A module for an optical device according to the invention is characterized by being used as a module for a camera.

According to the invention, a manufacturing method of a module for an optical device being provided with a solid-state image sensor having an effective pixel region formed on one side thereof, and an optical path demarcating unit for demarcating an optical path to the effective pixel region, is characterized by comprising steps of: placing a transparent cover so as to oppose to the effective pixel region; bonding the transparent cover to the solid-state image sensor; and joining the optical path demarcating unit to the transparent cover.

A manufacturing method of a module for an optical device according to the invention is characterized in that the step of joining the optical path demarcating unit to the transparent cover is executed by bonding the transparent cover and the optical path demarcating unit.

A manufacturing method of a module for an optical device according to the invention is characterized in that a photosensitive bonding agent is used for bonding the solid-state image sensor and the transparent cover.

A manufacturing method of a module for an optical device according to the invention is characterized in that bonding of the solid-state image sensor and the transparent cover is executed by patterning the photosensitive bonding agent at the peripheral portion of the effective pixel region on the one side of the solid-state image sensor.

A manufacturing method of a module for an optical device according to the invention is characterized by further comprising a step of bonding the solid-state image sensor to a plane portion of an image processing device bonded to a wiring substrate.

A manufacturing method of a module for an optical device according to the invention is characterized in that the module for an optical device is used as a module for a camera.

In the module for an optical device and its manufacturing method according to the invention, the lens holder is joined (bonded) to the transparent cover with the surface of the transparent cover defined as a positioning reference for the lens, whereby the optical distance between the lens and the solid-state image sensor precisely agrees with the focal length of the lens, regardless of the state of the wiring substrate. Further, the optical axis of the lens and the vertical axis of the solid-state image sensor (effective pixel region) precisely agree with each other.

Moreover, in the module for an optical device and its manufacturing method according to the invention, the plane size of the transparent cover is formed to be smaller than the plane size of the one side (the surface having the effective pixel region) of the solid-state image sensor, whereby the module for an optical device can be made compact. In case where the module is used as a camera module, in particular, a camera itself is minimized.

Moreover, in the module for an optical device and its manufacturing method according to the invention, the bonding portion for bonding the solid-state image sensor and the transparent cover contains a photosensitive bonding agent, whereby the bonding portion is easily and efficiently formed with high precision by patterning with a photolithography technique. Further, the bonding portion can similarly be formed on either the solid-state image sensor and the transparent cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A module for an optical device according to the invention will be described below with reference to drawings showing its preferred embodiment.

FIG. 5is a schematic plan view showing a plane shape of a solid-state image sensor, according to a first constructional example, used in a module for an optical device according to the invention.FIG. 6is a schematic sectional view taken along line A—A inFIG. 5. Reference numeral1denotes the solid-state image sensor which is formed on a semiconductor substrate such as silicon with a semiconductor processing technique. An effective pixel region2for performing a photoelectric conversion is formed at the center portion of one side (the surface on which a lens13described later is placed: this surface will be hereinafter referred to as an upper surface) of the solid-state image sensor1. Formed at the peripheral portion of the solid-state image sensor1are bonding pads3that are connecting terminals for establishing a connection to an external circuit and perform input/output of an electrical signal or the like. A transparent cover5arranged opposite to the effective pixel region2is bonded via a bonding portion4to the upper surface of the solid-state image sensor1having the effective pixel region2formed thereon. The transparent cover5protects (the surface of) the effective pixel region2from external moisture, dust (scrap) or the like. The bonding portion4is formed at the outside of the outer periphery of the effective pixel region2on the upper surface of the solid-state image sensor1for bonding the transparent cover5to the solid-state image sensor1. The transparent cover5transmits incident light from the outside, whereby the solid-state image sensor1makes the effective pixels (light-receiving elements) arranged on the effective pixel region2receive the incident light (detect the incident light). The transparent cover5is made of a transparent material such as glass or the like. The transparent cover5opposes to the effective pixel region2to cover at least the entire effective pixel region2, thereby protecting the effective pixel region2from the outside environment. The plane size of the transparent cover5is formed to be smaller than the plane size of the upper surface of the solid-state image sensor1, thereby being capable of making the module for an optical device compact. In case where the module is used as a camera module, in particular, a small-sized camera having excellent portability can be realized.

In case where the transparent cover5is bonded by the bonding portion4at the outside region of the effective pixel region2, it is preferably to form a space between the effective pixel region2and the transparent cover5in the upper surface of the solid-state image sensor1. To form the space between the effective pixel region2and the transparent cover5allows incidence of light transmitted through the transparent cover5from the outside to the effective pixel region2as it is, so that optical loss does not occur on the way of the optical path. Specifically, to form the space between the effective pixel region2and the transparent cover5can maintain transparent property even after forming the transparent cover5.

The outer periphery of the space formed between the effective pixel region2and the transparent cover5, both being arranged so as to be opposite to each other, is preferably sealed perfectly with the bonding portion4. Perfectly sealing the outer periphery of the space formed between the effective pixel region2and the transparent cover5can prevent the occurrence of the defect on the effective pixel region2caused by an invasion of moisture, invasion and adherence of dust, scratch or the like on (the surface of the effective pixel region2during the subsequent processes. This allows to realize a solid-state image sensor (i.e., a module for an optical device) having excellent production yield and high reliability.

In case where the solid-state image sensor1is built in an optical device such as a digital still camera or a video camera, the transparent cover5is required to have a function of shielding infrared rays from the outside in addition to the function of protecting the surface of the effective pixel region2from dust, scratch or the like. In this case, an infrared ray shielding film can be formed on the surface of the transparent cover5in order that it functions as an optical filter.

The bonding portion4can be formed by uniformly applying a bonding agent obtained by mixing a photosensitive bonding agent such as, for example, UV (Ultraviolet Ray) curable resin that is an acryl-based resin and a thermosetting resin such as, for example, an epoxy-based resin, on the upper surface of the solid-state image sensor1(or the transparent cover5), whereupon a patterning is performed by using a known photolithography technique. In case where plural solid-state image sensors1are manufactured on a semiconductor wafer, the bonding portion4can simultaneously be formed with respect to the respective plural solid-state image sensors1. Instead of this, in a state of a transparent plate material (base material of the transparent cover5) before plural transparent covers5are independently cut, the bonding portion4can simultaneously be formed with respect to the respective plural transparent covers5. In either case, the bonding portion4can efficiently be formed.

The reason why the photosensitive bonding agent is mixed with the thermosetting resin is as follows. Mixing the photosensitive bonding agent with the thermosetting resin can give photosensitivity to the bonding agent, whereby the patterning of the bonding portion4can easily be performed with high precision by carrying out a process such as exposure and development with the photolithography technique. The fact that the patterning of the bonding portion4can be performed with high precision means that the bonding portion4can be formed with high precision even in case where the region other than the effective pixel region2on the solid-state image sensor1is narrow. Usable patterning methods of the bonding portion4include, in addition to the above-mentioned photolithography technique, a method wherein a bonding agent (e.g., an epoxy resin or the like) is patterned with a printing method, a method wherein a bonding agent is patterned with a dispense method and a method using a bonding sheet formed into a frame. It is possible to appropriately select any one of them according to need.

The transparent cover5may be bonded to the individual solid-state image sensor1independently, but when plural solid-state image sensors1are formed on a wafer, the transparent cover5can simultaneously be bonded to all solid-state image sensors1, with the result that the transparent cover5can efficiently be formed. For example, a single transparent plate material (base material of the transparent cover5) is arranged so as to be opposite to all plural solid-state image sensors1formed on the semiconductor wafer, whereupon the transparent plate material is simultaneously bonded to the bonding portion4formed corresponding to all solid-state image sensors1. Then, the transparent plate material (base material of the transparent cover5) is cut so as to correspond to each solid-state image sensor1, thereby forming the transparent cover5on each solid-state image sensor1. Further, contrary to this, the bonding portion4is formed in advance on the transparent plate material (base material of the transparent cover5) so as to correspond to each solid-state image sensor1, whereupon the transparent plate material (transparent cover5) is bonded to the solid-state image sensors1formed on the semiconductor wafer and, then, cut so as to correspond to each solid-state image sensor1, thereby forming the transparent cover5on each solid-state image sensor1. Moreover, the plane size of the transparent cover5formed as described above can be smaller than the plane size of the upper surface of the solid-state image sensor1, thereby achieving the small-sized solid-state image sensor1. It is noted that the transparent cover5aims to protect the effective pixel region2of the solid-state image sensor1from the outside environment, so that it may be formed by any method so long as the same effect can be achieved.

FIG. 7is a schematic plan view showing a plane shape of a solid-state image sensor, according to a second constructional example, used in a module for an optical device according to the invention.FIG. 8is a sectional view taken along line B—B inFIG. 7. This second constructional example has basically the same construction as that of the first constructional example shown inFIG. 5andFIG. 6, so that the same and corresponding constituent elements are given by the same numerals and its description will not be given. This second constructional example shows the case where the plane size of the transparent cover5in one direction (the size in the side-to-side direction inFIG. 7) is greater than the solid-state image sensor1. This second constructional example can be applied to the case where the transparent cover5having the plane size greater than the solid-state image sensor1is required to be bonded.

FIG. 9is a schematic sectional view showing a section of a module for an optical device according to the invention, to which the above-mentioned solid-state image sensor1is incorporated. The plan view of the module for an optical device is not be given. The basic shape thereof is a rectangle (square or rectangle) seen in a plane, and it can appropriately be changed according to need. Further, constituent elements same as or corresponding to the constituent elements inFIG. 5throughFIG. 8are given by the same numerals, and its detailed description will not be given.

A module20for an optical device is constructed by a wiring substrate6having a conductive wiring7patterned on both front and back surfaces, a solid-state image sensor1, a DSP (Digital Signal Processor)8as an image processing device that controls the operation of the solid-state image sensor1and processes a signal outputted from the solid-state image sensor1, and a lens holder10that is placed opposite to the solid-state image sensor1and functions as an optical path demarcating unit for demarcating an optical path to the solid-state image sensor1(to an effective pixel region2not shown inFIG. 9). The solid-state image sensor1has a configuration shown inFIG. 5andFIG. 6or inFIG. 7andFIG. 8. Therefore, the transparent cover5bonded on the surface of the solid-state image sensor1with the bonding portion4and the lens holder10are joined at a joint portion11. The lens holder10holds a lens13at its inner periphery on the upper end portion. The lens holder10is formed such that its lower end portion is widened rather than its upper end portion. The size of the widened lower end portion of the lens holder10approximately agrees with the size of the peripheral portion of the wiring substrate6. Different from the above-mentioned conventional example, the lower end portion of the lens holder10is not bonded to the wiring substrate6, but a gap is normally formed between the upper surface of the wiring substrate6and the lower end portion of the lens holder10in the module20for an optical device according to the invention. This gap is referred to as an adjusting portion12, the detail of which is described later.

Specifically, the lens holder10is indirectly fixed to the wiring substrate6via the DSP8, spacer9, solid-state image sensor1, bonding portion4and transparent cover5, but it is directly fixed to the transparent cover5. Therefore, the relative positional relationship between the lens13held by the lens holder10and the transparent cover5and the relative positional relationship between the transparent cover5and the solid-state image sensor1are not influenced by the state of the wiring substrate6, so that the relative positional relationship between the lens13and the solid-state image sensor1(effective pixel region2) is not also influenced by the state of the wiring substrate6.

As shown inFIG. 5throughFIG. 8, the solid-state image sensor1used in the module20for an optical device according to the invention has the effective pixel region2on its upper surface, wherein the transparent cover5is bonded with the bonding portion4so as to cover the effective pixel region2. The module for an optical device according to the invention can be minimized (made thin-sized, made light-weight) by mounting the solid-state image sensor1wherein the transparent cover5having a plane size smaller than that of the upper surface of the solid-state image sensor1is mounted (bonded with the bonding portion4) opposite to the effective pixel region2as described above. Further, the wiring substrate6, DSP8, solid-state image sensor1and transparent cover5are laminated to form a laminate structure, thereby being capable of realizing a further minimization.

The module20for an optical device is assembled as schematically described below. At first, the DSP8is placed and die-bonded on the upper surface (inFIG. 9, the surface on which the lens13is placed) of the wiring substrate6having formed thereon the conductive wiring7, and further, each connecting terminal of the DSP8is connected to the conductive wiring7by a bonding wire8w. It is noted that a passive member (not shown) such as a resistance or the like may be mounded on both surfaces of the wiring substrate6in addition to the DSP8. Subsequently, the surface of the solid-state image sensor1on which the transparent cover5is not bonded is placed and die-bonded on the upper surface of the DSP8via the spacer9that is a sheet-shaped insulative bonding agent. Further, each connecting terminal of the solid-state image sensor1is connected to the conductive wiring7by a bonding wire1w. The DSP8is preferably a semiconductor chip (bare chip) from the viewpoint of minimization, but it may be a packaged one (resin encapsulation) with, for example, CSP (Chip Size Package) technique. When the DSP8is packaged, the spacer9and bonding wire8ware unnecessary, whereby the connecting terminal led from the package may directly be connected to the conductive wiring7and the solid-state image sensor1may directly be bonded on the plane portion of the upper surface of the package.

Thereafter, a bonding agent is applied on the peripheral portion (the portion corresponding to the joint portion11) on the exposed surface (upper surface inFIG. 9) of the transparent cover5and, then, the transparent cover5and the lens holder10are positioned to be joined (bonded) by the bonding agent applied on the joint portion11, thereby forming the module20for an optical device according to the invention. Specifically, in the module20for an optical device according to the invention, the lens holder10can be positioned with the upper surface (the surface on the lens13side) of the transparent cover5defined as a positioning reference of the lens13. An epoxy-based resin whose viscosity is adjusted for achieving a thin application is suitable for the bonding agent used for the joint portion11, but a sheet-shaped bonding agent may be used that is shaped in advance into a rectangular frame corresponding to the joint portion11, i.e., corresponding to the peripheral portion of the transparent cover5.

As described above, in the module20for an optical device according to the invention, the lens holder10(in other words, the lens13) is positioned with the surface of the transparent cover5defined as the positioning reference of the lens13, whereby the optical distance between the solid-state image sensor1and the lens13can correctly and precisely be agreed with the focal length f of the lens13. It is needless to say that, in this case, the thickness of the bonding portion4and the thickness of the transparent cover5are considered in advance. The lens holder10has a function of an optical path demarcating unit for demarcating an optical path to the solid-state image sensor1(transparent cover5) and a function of protecting means for protecting the solid-state image sensor1and the DSP8from the external environment in addition to the function of holding the lens13. The lens13and the lens holder10are preferably formed in one body in advance, but not limited thereto. The lens13may be assembled separately to the lens holder10. In this case, the specification of the lens13can freely be changed, thereby being capable of manufacturing a module for an optical device having wide general-purpose property. Moreover, a shutter function may be given to the lens holder10.

The adjusting portion12is shown inFIG. 9that is a gap formed between the wiring substrate6and the lens holder10for describing the effect. However, the wiring substrate6and the lens holder10may be bonded by filling a bonding agent in this adjusting portion12. In case where the wiring substrate6and the lens holder10are bonded by the bonding agent in the adjusting portion12, the semiconductor device such as the solid-state image sensor1or the DSP8is perfectly sealed by the wiring substrate6and the lens holder10. This can prevent the external influence on the solid-state image sensor1, the DSP8or the like, thereby being capable of further enhancing reliability. In case where the adjusting portion12is bonded by the bonding agent, it is configured such that the influence caused by the warp or distortion of the wiring substrate6is absorbed between the joint portion11and the adjusting portion12in the lens holder10, while the same influence is absorbed between the end portion of the DSP8and the adjusting portion12in the wiring substrate6, resulting in preventing the influence of a stress caused on the joint portion11due to the bonding of the adjusting portion12. Moreover, the influence of the stress caused on the joint portion11with the deformation of the wiring substrate6can further be reduced if the bonding agent having flexibility greater than that of the bonding agent used at the joint portion11is used for the adjusting portion12.

Although the above-mentioned embodiment is described with the case where the transparent cover5and the lens holder10are joined by the bonding agent, the joint method in the joint portion11is not limited to the bonding. The transparent cover5and the lens holder10may be engaged with each other. For example, an engagement (threaded engagement) with a screw, or fitting mechanism may be applied. Specifically, any joint method may be applied so long as the transparent cover5and the lens holder10are joined with (the surface of) the transparent cover5defined as the positioning reference of the lens13. In the module for an optical device according to the invention, the lens holder10only has a configuration that can hold the lens13and can be joined to the transparent cover5as described above, so that the focus adjuster required in the conventional module for an optical device is unnecessary, thereby simplifying the structure and realizing small-sized (light-weight) and low-cost module.

FIG. 10throughFIG. 13are schematic sectional views each showing a process for describing a manufacturing method of the module for an optical device according to the invention. The constituent elements same as those inFIG. 9are given by same numerals; therefore, description thereof will not be repeated herein.FIG. 10shows a multiple wiring substrate21wherein plural wiring substrates6are connected. The multiple wiring substrate21has the plural wiring substrates6, each corresponding to each module20, connected in, for example, a matrix or in a long-sized manner. Using the multiple wiring substrate21can simultaneously manufacture the plural modules20for an optical device so as to correspond to each wiring substrate6. The multiple wiring substrate21is divided by a parting line6ainto an area corresponding to each wiring substrate6, and finally separated into each wiring substrate6(each module20for an optical device) by being divided by the parting line6a. Described below is a process for simultaneously manufacturing the plural modules20by using the multiple wiring substrate21. It is noted that the module20for an optical device according to the invention may be manufactured by using the individual wiring substrate6separated individually at the beginning without using the multiple wiring substrate21.

A ceramic substrate, glass epoxy resin substrate, alumina substrate or the like can be used for the multiple wiring substrate21. The thickness of the multiple substrate21is preferably about 0.05 through 2.00 mm in order to maintain a mechanical strength. The conductive wiring7is patterned on the multiple wiring substrate21so as to correspond to each wiring substrate6.FIG. 10shows the case where the conductive wiring7is formed on both surfaces of the multiple wiring substrate21. The conductive wiring7may be formed only on one surface of the multiple wiring substrate21, but considering the mounting density, it is preferable that the conductive wiring is formed on both surfaces to lead the connecting terminal for establishing a connection to the outside from the surface of the wiring substrate6on which the solid-state image sensor1is mounted and its opposite surface. The conductive wirings7formed on both surfaces of the wiring substrate6are connected to each other within the wiring substrate6(not shown). Further, the conductive wiring7is appropriately designed in accordance with the specification of the intended module20for an optical device. The same process is simultaneously performed in the adjacent wiring substrate6connected to each other in the multiple wiring substrate21, so that the manufacturing process for one wiring substrate6will be described and the description about the adjacent wiring substrate6will not be given.

FIG. 11is a schematic view showing a mounting state of the DSP8. The DSP8is placed and die-bonded on the upper surface of the wiring substrate6(multiple wiring substrate21) having the conductive wiring7formed thereon. Thereafter, (the connecting terminal of) the DSP8and the conductive wiring7are wire-bonded with the bonding wire8wto thereby be electrically connected. A flip chip bonding may be used instead of the wire bonding as the connection method.

FIG. 12is a schematic view showing a mounting state of the solid-state image sensor1. After the DSP8is mounted as described above, the spacer9that is a sheet-shaped insulative bonding agent is placed on the plane portion of the top surface of the DSP8, and the DSP8and the spacer9are bonded to each other. The material suitable for the spacer9is the one that has an insulating property and bonding property and has a slight shock-absorbing property upon the bonding so as not to affect on the surface of the DSP8. Examples of the suitable spacer9include sheet-shaped resin made of acryl or the like with a thickness of about 0.05 through 1.00 mm. Subsequently, the solid-state image sensor1is placed on the upper surface of the spacer9and die-bonded to the spacer9. Thereafter, (the connecting terminal of) the solid-state image sensor1and the conductive wiring7are wire-bonded by the bonding wire1wto thereby be electrically connected. The transparent cover5is preferably formed in advance (before the solid-state image sensor1is placed on the spacer9) on the upper surface of the solid-state image sensor1from the viewpoint of preventing the occurrence of the defect such as a scratch on the surface of the solid-state image sensor1.

FIG. 13is a schematic view showing a mounting state of the lens holder10. After the bonding agent is applied to the joint portion11of the transparent cover5in each wiring substrate6, the lens holder10(and the lens13) is appropriately positioned to the transparent cover5, whereupon the transparent cover5and the lens holder10are bonded to each other by the bonding agent applied to the joint portion11. The wiring substrate6and the lens holder10may be bonded to each other by applying the bonding agent having flexibility to the adjusting portion12. Plural lens-fitted modules20for an optical device are formed corresponding to each wiring substrate6on the multiple wiring substrate21by the process shown inFIG. 13. Thereafter, the plural modules20for an optical device formed on the multiple wiring substrate6are divided (cut) along the parting line6aby using a dicing, rooter, press-die or the like to thereby be separated one by one, resulting in obtaining an individual module20for an optical device shown inFIG. 9.

In case where the lens13and the lens holder10are made as one body and the lens holder10is joined to the transparent cover5, the solid-state image sensor1and the DSP8can surely be protected in the following processes, and moreover, a further small-sized module for an optical device can be manufactured. Further, the positioning of the lens13to the solid-state image sensor1can be simplified with enhanced precision, thereby being capable of providing uniformity in optical characteristic of the module for an optical device. Although the lens holder10is made individual corresponding to each wiring substrate6in the above-mentioned description, a multiple lens holder wherein the plural lens holders10are connected to each other may be used corresponding to the multiple wiring substrate21. In this case, the positioning process of the lens holder10to the transparent cover5can further be simplified.

Moreover, the solid-state image sensor1having the effective pixel region2protected by the transparent cover5is mounted on the module20for an optical device, whereby there is no fear that dusts are adhered onto the surface of the effective pixel region2of the solid-state image sensor1in the processes subsequent to the process of mounting the solid-state image sensor1. Therefore, the module20for an optical device can be manufactured even under environment having relatively low cleanness. Consequently, the module for an optical device and its manufacturing method can be realized wherein the yield is improved, process is simplified and cost is reduced. Moreover, using the multiple wiring substrate21having the plural wiring substrates6connected to each other can simultaneously manufacture the plural modules20for an optical device, so that the production efficiency of the module for an optical device can further be enhanced and the characteristic of the module for an optical device can be unified.

FIG. 14throughFIG. 16are schematic sectional views for describing the effect of the module for an optical device according to the invention.FIG. 14shows a case where the center portion of the wiring substrate6has a convex shape toward the lens13. In this case, the peripheral portion of the wiring substrate6is apart from the lens13compared to the center portion of the same, so that the adjusting portion12, i.e., the gap between the lens holder10and the wiring substrate6is widened. However, the lens holder10is bonded to the transparent cover5at the joint portion11, not to the wiring substrate6, whereby the optical distance between the lens13and the solid-state image sensor1is kept to be matched with the focal length f of the lens13, and hence, the parallel relationship between the lens13and the solid-state image sensor1is also maintained. Specifically, even if the wiring substrate6is deformed as shown inFIG. 14in the module for an optical device according to the invention, the positional change of the lens13to the solid-state image sensor1does not occur, whereby the position of the lens13with respect to the solid-state image sensor1is not required to be adjusted. Moreover, the parallel relationship between the lens13and the solid-state image sensor1is also always maintained, whereby an image of a subject is correctly projected onto the solid-state image sensor1.

FIG. 15shows a case where the center portion of the wiring substrate6has a concave shape toward the lens13. In this case, the peripheral portion of the wiring substrate6approaches the lens13compared to the center portion of the same, so that the adjusting portion12, i.e., the gap between the lens holder10and the wiring substrate6is decreased. However, the lens holder10is bonded to the transparent cover5at the joint portion11, not to the wiring substrate6, whereby the optical distance between the lens13and the solid-state image sensor1is kept to be matched with the focal length f of the lens13, and hence, the parallel relationship between the lens13and the solid-state image sensor1is also maintained. Specifically, even if the wiring substrate6is deformed as shown inFIG. 15in the module for an optical device according to the invention, the positional change of the lens13to the solid-state image sensor1does not occur, whereby the position of the lens13with respect to the solid-state image sensor1is not required to be adjusted. Moreover, the parallel relationship between the lens13and the solid-state image sensor1is also always maintained, whereby an image of a subject is correctly projected onto the solid-state image sensor1.

FIG. 16is a schematic view showing a case where the thickness of the wiring substrate6is not uniform. In the example shown inFIG. 16, the thickness is great at the right-side end portion (right end in the figure) of the wiring substrate6, while the thickness is small at the left-side end portion (left end in the figure) thereof. Assuming that the plane shape of the wiring substrate6is a rectangular, each side having approximately 10 mm, and the difference of the thickness between at the opposing ends of the wiring substrate6is ±0.01 mm in case where the thickness of the wiring substrate6is different at the opposing ends. Even if the thickness itself of the wiring substrate6is within the specification, the left-side end portion of the wiring substrate6is apart from the lens13compared to the center portion of the same, so that the adjusting portion12at the left-side end portion of the wiring substrate6is widened. On the contrary, the right-side end portion of the wiring substrate6approaches the lens13compared to the center portion of the same, so that the adjusting portion12at the right-side end portion of the wiring substrate6becomes narrow. However, the lens holder10is bonded to the transparent cover5at the joint portion11, not to the wiring substrate6, whereby the optical distance between the lens13and the solid-state image sensor1is kept to be matched with the focal length f of the lens13, and hence, the parallel relationship between the lens13and the solid-state image sensor1is also maintained. Specifically, even if the thickness of the wiring substrate6is not uniform as shown inFIG. 16in the module for an optical device according to the invention, the positional change of the lens13to the solid-state image sensor1does not occur, whereby the position of the lens13with respect to the solid-state image sensor1is not required to be adjusted. Moreover, the optical axis of the lens13is always agreed with the vertical axis of the solid-state image sensor1, and the parallel relationship between the lens13and the solid-state image sensor1is also always maintained, whereby an image of a subject is correctly projected onto the solid-state image sensor1.

As mentioned above in detail, the module for an optical device according to the invention employs a configuration wherein the transparent cover5and the lens holder10are joined (bonded) to each other with the surface of the transparent cover5defined as the positioning reference of the lens13, thereby being capable of correctly and precisely fixing and maintaining the positional relationship between the lens13and the solid-state image sensor1. Specifically, the optical distance between the lens13and the solid-state image sensor1can precisely be matched with the focal length of the lens13, and the optical axis of the lens13and the vertical axis of the solid-state image sensor1(more specifically, the surface of the effective pixel region2) can precisely be agreed with each other (the parallel relationship between the lens13and the solid-state image sensor1can be maintained), whereby the optical distance between the solid-state image sensor1and the lens13is not required to be adjusted even if the wiring substrate6is deformed. Moreover, even if the thickness of the wiring substrate6is not uniform, the optical axis of the lens13and the vertical axis of the solid-state image sensor1can be agreed with each other, whereby an image of a subject can correctly be projected onto the solid-state image sensor1. Accordingly, it is unnecessary to provide a focus adjuster that is required in the conventional module for an optical device for adjusting the optical distance between the lens and the solid-state image sensor, and further, a process for a focus adjustment is unnecessary.

Additionally, since the focus adjuster is unnecessary in the invention, the number of the constituent elements can be reduced, thereby being capable of minimizing (making thin-sized and light-weight) the module for an optical device. Moreover, a facility for manufacture and manufacturing process can be simplified, resulting in being capable of enhancing the yield, reducing the material cost and production cost and achieving low cost.

Further, according to the module for an optical device according to the invention, the plane size (longitudinal and lateral sizes of the plane) of the transparent cover5is formed smaller than the plane size (longitudinal and lateral sizes of the plane) of the upper surface (the surface having the effective pixel region) of the solid-state image sensor1, thereby being capable of minimizing the module for an optical device is achieved. Using the module as a camera module, in particular, can further promote the minimization of the camera.

Moreover, in the module for an optical device according to the invention, a photosensitive bonding agent is used for the bonding portion4that bonds the solid-state image sensor1and the transparent cover5, whereby a patterning be performed by using a photolithography technique. Therefore, the bonding portion4between the solid-state image sensor1and the transparent cover5can easily and efficiently be formed with high precision. Moreover, the bonding portion4can be formed by utilizing either side of the solid-state image sensor1and the transparent cover5, so that any selection can be made in accordance with the circumstance during the manufacturing process.