The present application claims priority from Japanese patent application No. 2003-329700, filed on Sep. 22, 2003, the content of which is hereby incorporated by reference into this application.
The present invention relates to a solid state image sensing device and to a method of manufacture thereof; and, more particularly, the invention relates to a technique that is effective when applied to a solid state image sensing device of the type used for mobile communication devices, such as cellular phones, and to a technique for the manufacture thereof.
Solid state image sensing devices operate as photoelectric converters which convert light signals from an image into electric signals according to the arrangement of pixels in the image. Over the main surface of a substrate of a solid state image sensing device, an image sensing element has been mounted with its light receiving surface facing up. Above the image sensing element, a filter and a lens are disposed in this order, and these elements are supported by a frame.
Japanese Unexamined Patent Publication No. 2003-169235 describes a technique relating to an image sensing device provided with a cylindrical housing, a condenser lens that is mounted on an opening on one side of the housing to collect light received through the opening, and a circuit substrate having a sensor element mounted thereon in an opening on the other side of the housing for receiving light captured from the condenser lens. The circuit substrate is fitted in the opening on the other side of the housing, and the circuit substrate is adhered to the boundary face of the housing.
Japanese Unexamined Patent Publication No. 2003-172859 describes a technique relating to a camera module equipped with a solid state image sensing device, a lens unit having a lens for guiding light to the solid state image sensing device, a lens holder for holding the solid state image sensing device and also a lens joint portion attached so that the position of the lens can be adjusted to have a predetermined focal distance between the lens and the solid state image sensing device, and a shielding cap for shielding the lens joint portion of the lens holder and the lens unit to permit light to enter the lens unit.
Japanese Unexamined Patent Publication No. 2002-62462 describes a manufacturing technique used in the fabrication of a lens integrated type solid state image sensing device, comprising the steps of: using one surface (the light receiving surface) of a transparent substrate or an optical filter as a reference plane, face-down mounting a solid state image sensing device on the other surface; and, using the light receiving surface as a reference plane, forming a lens holder having a recess to support a lens therein.
Japanese Unexamined Patent Publication No. 2001-292365 describes a technique related to an image sensing device obtained by disposing an image sensing element having a light receiving portion over a substrate; forming, with a resin, a sealing portion for sealing a connecting means for electrically connecting the image sensing element to the substrate and a side wall portion for opening the light receiving portion; and fixing a lens-barrel for supporting an imaging lens, which provides the light receiving portion with an image, to the side wall portion made of resin by a fixing means.
A investigation by the present inventors has resulted in the following findings.
Various optical parts, such as an image sensing element, a filter and a lens are used for a solid state image sensing device. If some foreign materials attach to them, images taken and displayed by the solid state image sensing device will have an inferior quality. The solid state image sensing device is therefore sensitive to various inconveniences, such as invasion of foreign materials during its manufacturing steps, and its reliability and production yield tend to be lowered by them.
An object of the present invention is to provide a solid state image sensing device which exhibits an improvement in the production yield, and to a method of manufacture thereof.
The above-described and other objects and novel features of the invention will be apparent from the following description herein and the accompany drawings.
Of the aspects and features of the invention disclosed in the present application, typical ones will next be described briefly.
In the solid state image sensing device according to the invention, a frame attached to a wiring substrate so as to cover an image sensing element and a lens holder having a lens built therein are thermally welded.
In the solid state image sensing device of the invention, a passive part is mounted over the wiring substrate via a Pb-free solder.
In the solid state image sensing device of the invention, an outer wall of the frame attached to the wiring substrate to cover the image sensing device has been threaded and a lens holder having a threaded inner wall is attached to the threaded outer wall of the frame.
In the solid state image sensing device of the invention, the outer surface is covered with a conductor cover.
A method of manufacture of a solid state image sensing device according to the invention comprises the steps of subjecting a wiring substrate to plasma washing treatment, mounting an image sensing element over the wiring substrate and electrically bonding an electrode of the image sensing element to an electrode of the wiring substrate via a bonding wire.
Another aspect of the method of manufacture of a solid state image sensing device according to the invention comprises the step of, upon mounting a frame to cover therewith an image sensing element over a wiring substrate via a bonding material and heating to set the bonding material, making a hole for discharging a gas, which has been expanded due to the heating, from the inside to the outside of the frame in advance.
A further aspect of the method of manufacture of a solid state image sensing device according to the invention comprises the steps of bonding frames to respective product regions over the main surface of a wiring substrate in such a manner as to cover image sensing elements, adhering a sheet of a protective film across all the frames of the product regions, and separating the wiring substrate into respective product regions by cutting while the protective film adheres to the frame of each of the product regions.
A still further aspect of the method of manufacture of a solid state image sensing device according to the invention comprises the steps of bonding a frame to a wiring substrate to cover an image sensing element, mounting a lens holder having a lens built therein onto the frame and thermally welding the lens holder and the frame.
Advantages available by the typical aspects of, the invention disclosed herein will next be described briefly.
The production yield of a solid state image sensing device can be improved by thermally welding a frame bonded to a wiring substrate to cover an image sensing element and a lens holder having a lens built therein.
The production yield of a solid state image sensing device can be improved by mounting a passive element onto a wiring substrate via a Pb-free solder.
The production yield of a solid state image sensing device can be improved by threading an outer wall of a frame bonded to a wiring substrate to cover an image sensing element and fitting, in the frame, a lens holder having a threaded inner wall.
The performance of a solid state image sensing device can be improved by covering the outer surface thereof with a conductor cover.
The production yield of a solid state image sensing device can be improved by subjecting a wiring substrate to plasma washing treatment, mounting an image sensing element over the wiring substrate and electrically bonding an electrode of the image sensing element to an electrode of the wiring substrate via a bonding wire.
The production yield of a solid state image sensing device can be improved by forming, upon mounting a frame over a wiring substrate via a bonding material to cover an image sensing element and heating to set the bonding material, a hole for discharging a gas, which has expanded due to heating, from the inside of the frame to the outside in advance in the frame.
The time necessary for the manufacture of a solid state image sensing device can be shortened by bonding frames to respective product regions over the main surface of a wiring substrate in such a manner as to cover the image sensing elements, adhering a sheet of a protective film across all the frames of the product regions, and separating the wiring substrate into respective product regions by cutting while the protective film adheres to the frame of each of the product regions.
The production yield of a solid state image sensing device can be improved by bonding a frame onto a wiring substrate to cover an image sensing element, mounting a lens holder having a lens built therein over the frame and thermally welding the lens holder and the frame.
Embodiments of the invention will be described specifically based on the accompanying drawings. In all of the drawings, elements having like function will be identified by like reference numerals, and overlapping descriptions thereof will be omitted. In the description of the embodiments, a description of the same or similar portion is not repeated in principle unless otherwise particularly necessary.
In the drawings used to illustrate the embodiments, hatching is sometimes given even to a plan view for easy viewing.
A solid state image sensing device representing an example of this Embodiment and its manufacturing steps will be described with reference to the drawings. The solid state image sensing device according to this embodiment is, for example, a camera module of the type used for an image input portion of a cellular phone, a TV phone, a PC camera, a PDA (personal digital assistants; mobile information terminal), an optical mouse, a door phone, a security camera, a fingerprint recognizer or a toy.
In this embodiment, the invention is applied to a 110,000-pixel CMOS (complementary metal oxide semiconductor) sensor camera module that supports the CIF (Common Immediate Format).
As illustrated in
The wiring substrate 2 has a multilayer wiring structure obtained by stacking, for example, an insulating layer made of a resin material layer (for example, a glass epoxy resin material layer) and a wiring layer (conductor layer). An electrode pad (bonding pad) 3a of the sensor chip 3, which is mounted over the surface 2a of the wiring substrate 2, is electrically connected to an electrode 12 that is formed over the surface 2a of the wiring substrate 2 via a bonding wire 11. An electrode pad (bonding pad) 7a of the logic chip 7, which is mounted over the reverse surface 2b of the wiring substrate 2, which represents a main surface on the wiring substrate 2, and an electrode pad (bonding pad) 8a of the memory chip 8 are electrically connected to an electrode 14 formed over the back surface 2b of the wiring substrate 2 via a bonding wire 13. The bonding wires 11 and 13 are each made of, for example, a gold (Au) wire. The passive part 9 is mounted over the back surface 2b of the wiring substrate 2 via a conductive bonding material 15 made of solder and is electrically connected to the electrode 14 that is formed over the back surface 2b of the wiring substrate 2.
The sensor chip 3, logic chip 7, memory chip 8 and passive part 9 are electrically connected, if necessary, via bonding wires 11 and 13, a conductor layer (conductor pattern) over the surface 2a, back surface 2b or inside of the wiring substrate 2, or an unillustrated conductor inside of a through-hole formed in the wiring substrate 2.
The sensor chip 3 is mounted over the surface 2a of the wiring substrate 2 with the main surface (light receiving surface, surface over which a light sensitive element is to be formed) up. The CMOS image sensor circuit formed over the sensor chip 3 is formed by the CMOS process, which is a standard process in the manufacture of a semiconductor device; and, it has a sensor array (light sensitive element region) and an analogue circuit for processing electric signals obtained in the sensor array. Light collected by the lens 6 disposed above the sensor chip 3 is caused to enter into the sensor array on the surface of the sensor chip 3. This sensor array consist of a plurality of light sensitive elements arranged regularly in a matrix along the main surface of the sensor chip 3. Each light sensitive element constitutes a pixel of the CMOS image sensor circuit and has a photoelectric converting function, that is, a function capable of converting incident light signals into electric signals. As this light sensitive element, a photo diode or photo transistor is, employed for example. This sensor chip 3 has, along the outer periphery of the main surface thereof, a plurality of electrode pads 3a. The bonding pads 3a constitute lead electrodes of the CMOS image sensor circuit of the sensor chip 3 and are electrically connected to the electrode 12 of the wiring substrate 2 and interconnects via a bonding wire 11.
The logic chip 7, memory chip 8 and passive part 9, which are mounted on the back surface of the wiring substrate 2, are electronic parts for system construction used for the processing of electric signals obtained mainly in the sensor chip 3 or for controlling the operation of the CMOS image sensor circuit of the sensor chip 3. The logic chip 7 has an arithmetic circuit for digital signal processing, for example, a DSP (Digital Signal Processor) formed thereover, and it functions to process electric signals sent from the sensor chip 3 at high speed. The memory chip 8 has a nonvolatile memory circuit, such as an EEPROM (Electrically Erasable Programmable Read-Only Memory), formed thereover. The passive part 9 is a passive element, such as a resistor element or capacitive element, and a chip part, such as chip resistor or chip condenser, can be used for it. As the binder material 15 for loading (mounting) the passive part 9 over the back surface 2b of the wiring substrate 2, use of a Pb-free solder is preferred, as will be described later. Use of a Sn—Ag solder (for example, Sn—Ag—Cu solder) having a relatively low melting point is more preferred.
The sealing resin 10 formed over the back surface 2b of the wiring substrate 2 is made of, for example, a thermosetting resin material, and it may contain a filler. The logic chip 7, memory chip 8, passive part 9 and bonding wire 13 are sealed and protected with the sealing resin 10.
The lens-barrel 4 and lens holder 5 are made of, for example, a resin material, such as PBT (polybutylene terephthalate) or a plastic material (insulating material), which may contain glass fibers. The lens-barrel 4 is bonded to the surface 2a of the wiring substrate 2 so as to cover the sensor chip 3. The adhesive surface 4b, which is the bottom surface at the foot part of the lens-barrel 4, is adhered (fixed) to the surface 2a of the wiring substrate 2 by a bonding material. On the side of a cylindrical head (cylinder portion) 4a of the lens-barrel 4, the lens holder 5 is attached so as to block the opening of the cylindrical head 4a of the lens-barrel 4. The inner wall (surface of the inner circumference) of the head 4a of the lens-barrel 4 and the outer wall (surface of the outer circumference of the cylinder portion) of the lower part of the lens holder 5 are provided with the screw threads. By turning the lens holder 5 to fit these threads and, thereby, inserting a portion of the lens holder 5 into the opening of the head 4a of the lens-barrel 4, the lens holder 5 is connected (attached) to the lens-barrel 4. By heating a portion of the head of the lens-barrel 4 to thermally weld the head 4a of the lens-barrel 4 and the screw threads (a portion of the screw) of the lens holder 5, the lens holder 5 is fixed to the lens-barrel 4.
The lens-barrel 4 has, in the cylinder portion thereof, a partition plate 4c for dividing it into an upper chamber and a lower chamber. An IR filter (IR glass filter) 16 is disposed or held at the opening portion of this partition plate 4c. The IR filter 16 functions to transmit visible light and block unnecessary infrared radiation having a wavelength greater than a predetermined wavelength. The IR filter 16 exists between the sensor chip 3 and lens 6 so that light outside of the camera module 1 is collected by the lens 6, passes through the IR filter 16 and then is irradiated to the sensor chip 3. The sensor chip 3 is disposed within a housing portion 4e of the lens-barrel 4, which is defined by the surface 2a of the wiring substrate 2, the foot part 4d of the lens-barrel 4, the partition plate 4c and the IR filter 16. The plane size of the housing portion 4e is greater than that of the head 4a of the lens-barrel 4. The lens 6 is fixed or held in the lens holder 5 by a holding member 17 made of, for example, copper.
To the surface 2a of the wiring substrate 2, on a portion thereof outside the lens-barrel 4, a flexible substrate (flexible wiring substrate) 21 is bonded (adhered) via an anisotropic conductive film (ACF) 22. The flexible substrate 21 is obtained by forming wiring patterns (conductor patterns) over a (flexible) base film (insulating film) that has an excellent bending strength, such as polyimide or polyester. The wiring pattern (not illustrated) formed over the flexible substrate 21 is electrically connected to a terminal portion (metal terminal portion, connection terminal, connector) 24 of the surface 2a of the wiring substrate 2 via conductor particles in the anisotropic conductive film 22. This terminal portion 24 is, if necessary, electrically connected to the electrode 12 over the surface 2a of the wiring substrate 2 or to the electrode 14 of the back surface 2b of the wiring substrate 2 via the conductor layer (conductor pattern) over the surface 2a, back surface 2b or inside of the wiring substrate 2, or via a conductor in an unillustrated through-hole formed in the wiring substrate 2. In other words, the terminal portion 24 is electrically connected to the circuit in the camera module 1 via the interconnect of the wiring substrate 2 and serves as an external terminal of the wiring substrate 2. The connector 25 formed at the end portion of the flexible substrate 21 is electrically connected to the terminal portion 24 of the wiring substrate 2 via a wiring pattern (not illustrated) of the flexible substrate 21 and functions as an external terminal (external connection terminal) of the camera module 1.
The steps employed in the manufacture of the solid state image sensing device according to this embodiment will be described next.
First, a wiring substrate 2c (wiring substrate base) as illustrated in FIGS. 2 to 4 is prepared.
The wiring substrate 2c is a base of the wiring substrate 2. The wiring substrate 2c, when cut and separated into respective product regions (substrate region) 30 in a cutting step, which will be described later, produces individual substrates which corresponds to the wiring substrate 2 of the camera module 1. The wiring substrate 2c has a plurality (48 pieces in the example of
As illustrated in
The wiring substrate 2c has a plurality of through-holes 31, called “boss holes”, in the vicinity of each product region 30. These through-holes 31 are used for alignment of the lens-barrel 4 and wiring substrate 2c. As will be described later, the lens-barrel 4 can be bonded to the wiring plate 2c while aligning the relative planar positions of the lens-barrel 4 and wiring substrate 2c, by inserting a positioning pin, called a “boss pin”, that is disposed on the lens-barrel 4, into the through-holes 31 of the wiring substrate 2c. These through-holes 31 are disposed outside the product region 30. In one product region 30, two through-holes 31 are disposed diagonally so as to sandwich the product region 30 therebetween. Similar to the through-holes of the conventional printed circuit board, the inner circumference surface of the through-holes 31 and the vicinity of its opening are covered with a conductor made of the same material as that used for the wiring material.
In the vicinity of the four sides of each of the surface 2a and the back surface 2b of the wiring substrate 2c, a plurality of conductor patterns 32, for example, in having a planar rectangular shape, are formed. In the vicinity of one side of the back surface 2b of the wiring substrate 2c, for example, a plurality of conductor patterns 33 having a planar rectangular shape are arranged at regular intervals. These conductor patterns 33 are disposed so as to facilitate peeling and removal of a resin (sealing material) cured in a runner from the wiring substrate 2c upon formation of the sealing resin 10. A sealing group is divided by a line with this conductor pattern 33. The conductor patterns 32 and 33 are made of, for example, copper, and they have a surface plated with, for example, nickel and gold. At diagonal corners of the wiring substrate 2c, through-holes 34 for alignment of the wiring substrate 2c and the manufacturing apparatus are formed.
After preparation of the wiring substrates 2c as illustrated in
In this Embodiment, Pb-free solder is preferably employed as the bonding material 15 in the mounting step of the passive part 9. Use of a Sn—Ag solder (for example, Sn—Ag—Cu solder) having a relatively low melting point is more preferred.
When a Sn—Sb solder having a high melting point is used as the bonding material 15, the solder reflow temperature becomes high (for example, about 290° C.) and the solder scattered during this solder reflow step may adhere onto the terminal portions 24 of the wiring substrate 2c. This may cause a short-circuit between the terminal portions 24, lower the reliability of the camera module thus manufactured and reduce the production yield of the camera module.
In this Embodiment, it is possible to prevent adhesion of the scattered solder onto the terminal portions 24 of the wiring substrate 2c by using, as the bonding material 15 for mounting the passive part therewith, a Sn—Ag solder having a relatively low melting point and carrying out reflow at a relatively low temperature (for example, about 230° C.). This results in an improvement of the reliability and production yield of the camera module.
In each product region 30, as illustrated in
The logic chip 7 and memory chip 8 (electrode pads 7a and 8a thereof) of each product region 30 are then electrically connected to the back surface 2b (electrode 14 thereof) of the wiring substrate 2c via a bonding wire 13 in the wire bonding step.
By a molding step (for example, transfer molding step) with a sealing mold, the sealing resin 10 is formed over the back surface 2b of the wiring substrate 2 so as to cover the logic chip 7, memory chip 8, passive part 9 and bonding wire 13 with the resin. The sealing resin 10 is made of, for example, a thermosetting resin and may contain a filler. A material having a low cure shrinkage (shrinkage upon curing) is preferably used for the sealing resin 10. Use of a dicycloepoxy resin is more preferred.
As the sealing method, a batch sealing method in which system parts (logic chip 7, memory chip 8 and passive part 9) of a plurality of product regions 30 are sealed in a batch manner is adopted. In this embodiment, however, the plurality of product regions 30 over the wiring substrate 2c are divided into a plurality of groups and system parts of the plurality of the product region 30 of each group are sealed in a batch manner. Over the back surface 2b of the wiring substrate 2c, the system parts of the plurality of product regions 30, which are disposed along the second direction Y of
In addition, the sealing resin 10 is provided in a separated form over the back surface 2b of the wiring substrate 2c, so that, compared with the entire sealing of the system parts of all the product regions 30 over the back surface 2b of the wiring substrate 2c, a stress to the wiring substrate 2c resulting from shrinkage of the sealing resin 10 can be relaxed, and, therefore, warpage or distortion of the wiring substrate 2c due to such stress can be reduced. Moreover, in order to partially narrow the width at the center in the longitudinal direction of each sealing resin 10 over the back surface 2b of the wiring substrate 2c, recesses 35 are formed to extend from the two long sides of the sealing resin 10 toward the center of its short side. These recesses 35 are formed symmetrically in two long sides of the sealing resin 10. It is also formed in an extra region outside the product region 30. When the sealing resin 10 has a strip planar shape without having the recess 35, there is a fear of the wiring substrate 2c warping toward the center of the longitudinal direction of the sealing resin 10 owing to stress upon shrinkage of the sealing resin 10; however, by narrowing the width at the center in the longitudinal direction of the sealing resin 10 formed over the back surface 2b of the wiring substrate 2c, such stress to the wiring substrate 2c due to the shrinkage of the sealing resin 10 can be relaxed further, and warpage or distortion of the wiring substrate 2c attributable to stress can be reduced further.
In this embodiment, a material having a low cure shrinkage (shrinkage upon curing) is used for the sealing resin 10. Use of a dicycloepoxy resin is more preferred. This makes it possible to reduce the shrinkage of the sealing resin 10 upon curing and to relax the stress to the wiring substrate 2c owing to the shrinkage of the sealing resin 10, leading to reduction in the warpage or distortion of the wiring substrate 2c, which will otherwise occur owing to the stress.
Formation of a groove in the sealing resin 10 by half dicing of the sealing resin 10 and wiring substrate 2c is possible as a measure for effecting relaxation of the stress applied to the wiring substrate 2c. According to the investigation by the present inventors, the stress to the wiring substrate 2c can be relaxed fully by not forming a groove in the sealing resin 10, but, as in this embodiment, by forming the sealing resin 10 in a separated form over the back surface 2b of the wiring substrate 2c, forming the recess 35 in the sealing resin 10 and using a material having a low cure shrinkage (shrinkage upon curing), preferably a dicycloepoxy resin, as the material of the sealing resin 10. By omitting half dicing of the sealing resin 10 and wiring substrate 2c, a step capable of generating foreign materials (dust) can be omitted, and the number of manufacturing steps can be reduced.
In this embodiment, warpage or distortion of the wiring substrate 2c can be reduced in the above-described manner, leading to the planarization of the wiring substrate 2c. Existence of warpage or distortion in the wiring substrate 2c may disturb smooth bonding of the bonding wire 11 in a bonding step of the bonding wire 11 after the sensor chip 3 is mounted over the surface (surface over which optical parts are to be mounted) 2a of the wiring substrate 2c. In this embodiment, on the other hand, the wiring substrate 2c can be planarized by reducing the warpage or distortion so that bondability of the bonding wire 11 can be improved. This leads to improvement in the production yield of the camera module. In addition, by planarizing the wiring substrate 2c, formation of a gap between the lens-barrel 4 and the wiring substrate 2c can be prevented upon adhesion of the lens-barrel 4 to the wiring substrate 2c, as will be described later. It also prevents invasion of foreign materials into the lens-barrel 4 from the gap between the wiring substrate 2c (wiring substrate 2) and the lens-barrel 4. As a result, adhesion of foreign materials to the sensor chip 3 or IR filter 16 can be suppressed or prevented, and, in turn, the production yield of the camera module can be improved.
FIGS. 12 to 14 are fragmentary side views of the camera module 1 during the manufacturing step following that of
After formation of the sealing resin 10 as described above, the surface (the surface over which the optical parts are to be mounted) 2a of the wiring substrate 2c, which is a main surface on the side opposite to the back surface (the surface over which the system parts are to be mounted) 2b, is subjected to plasma washing (plasma processing) 41, as illustrated in
As illustrated in
When foreign materials exist on the surface of the sensor chip 3 and the die bonding material 42 is baked at high temperature (about 150° C.), these foreign materials may be burnt into the surface of the sensor chip 3 during this baking treatment. Any foreign materials which have attached to the surface of the sensor chip 3 by burning cannot be removed easily, and they generate black spots in the image taken and displayed by the camera module.
In this embodiment, the die bonding material 42 is baked at a relatively low temperature, for example, at about 60 to 70° C. A baking temperature of the die bonding material 42 at 80° C. or less is preferred. This means that a bonding material (low-temperature setting type thermosetting bonding material) which sets by baking (heat treatment) at a relatively low temperature (for example, about 60 to 70° C.) is used as the die bonding material 42. This makes it possible to bake the die bonding material 42 at a relatively low temperature; and, even if foreign materials attach to the surface of the sensor chip 3, burning of them into the surface of the sensor chip 3 can be suppressed or prevented during baking of the die bonding material 42. Failures, such as black spots, can therefore be suppressed or prevented, which leads to improvement in the production yield of the camera module. The baking of the die bonding material 42 can be carried out at a relatively low temperature, whereby outgassing from the die bonding material 42 upon baking can be reduced and contamination of the surface of the sensor chip 3 by outgassing can be suppressed or prevented. This results in an improvement of the production yield of the camera module.
If the order of the die bonding and plasma washing 41 in this embodiment is reversed and the die bonding of the sensor chip 3 is followed by the plasma washing 41, the foreign materials which have attached to the surface of the sensor chip 3 during baking of the die bonding material 42 may be burnt into the surface of the sensor chip 3 during baking of the die bonding material 42. The foreign materials which have once been burnt into the surface of the sensor chip 3 cannot be removed easily, and black spots appear in the image taken and displayed by the camera module.
In this Embodiment, on the other hand, the sensor chip 3 is die-bonded after the plasma washing 41, as described above, whereby the sensor chip 3 is mounted over the wiring substrate 2c. The wiring substrate 2c is subjected to the plasma washing 41 without having the sensor chip 3 thereover, so that foreign materials are never burnt in the surface of the sensor chip 3 prior to plasma washing 41. Black spots resulting from the burning of the foreign materials into the surface of the sensor chip 3 can be suppressed or prevented and the production yield of the camera module can be improved. In addition, the surface of the electrode 12 over the surface 2a of the wiring substrate 2c can be cleaned by the plasma washing 41, resulting in the improvement in the bondability of the bonding wire 11 to the electrode 12.
Foreign materials (dust) which have attached to the surface of the sensor chip 3 are removed, for example, by adhering a pressure-sensitive adhesive sheet (pressure-sensitive adhesive tape) to the surface and then peeling it therefrom (Step S4). Foreign materials which have attached to (not burnt in) the surface of the sensor chip 3 after the baking treatment of the die bonding material 42 can be removed by this pressure-sensitive adhesive sheet. In this Embodiment, the baking treatment of the die bonding material 42 is carried out at a relatively low temperature so that, even if burning of foreign materials in the surface of the sensor chip 3 occurs upon baking treatment of the die bonding material 42, the burning-in degree is not so severe and the foreign materials burnt in the surface can be removed by the pressure sensitive adhesive sheet.
Washing (wet washing) with HFE (hydrofluoroether) is then performed (Step S5), by which organic substances which have attached to the surfaces of the electrode 12 and the sensor chip 3 over the surface 2a of the wiring substrate 2 can be removed. Foreign materials (for example, organic substances) which cannot be removed by the pressure-sensitive adhesive sheet can be removed effectively by this wet washing treatment with HFE. In addition, HFE can remove the foreign materials without adversely affecting the sensor chip 3.
The wire bonding step is then performed, as illustrated in
A lens-barrel 4, as illustrated in FIGS. 17 to 20, is then prepared.
In the cylinder of the lens-barrel 4, an IR filter 16 has already been installed. At this stage, at two opposing corners of the lens-barrel 4, when viewed from the top, and at the foot portions 4d of the lens-barrel 4, when viewed laterally, protrusions 51 extending almost horizontally along the surface (surface over which optical parts are to be mounted) 2a of the wiring substrate 2c are integrally formed with the lens-barrel 4. The protrusions 51 are members to be used for relative alignment of the planar position of the lens-barrel 4 and the wiring substrate 2c; and, on the back surface of them, a positioning pin 51a, called a boss pin, extending vertically relative to the surface 2a of the wiring substrate 2c, is formed (see
In each product region 30, as illustrated in FIGS. 23 to 26, the lens-barrel 4 (via the bonding material 53) is mounted over the surface 2a of the wiring substrate 2c so as to cover the sensor chip 3.
In each product region 30, as can be seen from
One example of a method of bonding the lens-barrel 4 to the wiring substrate 2c will be described next.
As illustrated in
The metal mask 63 is made, for example, of a metal material, and it has a mask portion 63a which is a metal plate region, a print region (coating region) 63b which is a region patterned in the mesh form, for example, by etching of the metal plate constituting the mask portion 63a, and a through-hole 63c from which a positioning pin 51a of the lens-barrel 4 protrudes.
The mask portion 63a of the metal mask 63 is a region without an opening portion. In the print region 63b of the metal mask 63, a metal material portion 63d remains in mesh form. Through a number of minute openings existing in the print region 63b, that is, minute gaps (openings) 63e between the metal material portions 63d, a bonding material can be applied (printed) to the adhesive surface 4b of the lens-barrel 4 located below the print region 63b.
After the metal mask 63 is placed over the lens-barrel jig 61, a predetermined amount of the bonding material 53 is applied onto the metal mask 63, as illustrated in
After application of the bonding material 53 to the adhesive surface 4b of the lens-barrel 4, the lens-barrel 4 is bonded to the surface 2a of the wiring substrate 2c over which the sensor chip 3 has been mounted and the bonding wire 11 has been formed.
Upon baking treatment of the bonding material 53, air (gas) in the lens-barrel 4 (housing portion 4e thereof) is expanded by heating. When the hole 52 is not formed in the lens-barrel 4, unlike this embodiment, air that has expanded in the lens-barrel 4 (housing portion 4e thereof) by the baking treatment passes out from between the adhesive surface 4b of the lens-barrel 4 and the surface 2a of the wiring substrate 2c, which may cause scattering of the bonding material 53, whereby and the bonding material 53 is inevitably deposited on the terminal portion 24 disposed in the outside vicinity region of the lens-barrel 4 over the surface 2a of the wiring substrate 2c. Adhesion of the bonding material 53 to the terminal portion 24 causes failure in electrical connection between the flexible substrate 21 and terminal portion 24, resulting in lowering of the production yield of the camera module. When a gap is formed between the adhesive surface 4b of the lens-barrel 4 and the surface 2a of the wiring substrate 2c by the passing of expanded air from the lens-barrel 4, foreign materials may enter from the gap in the subsequent steps and adhere to the sensor chip 3 or IR filter 16. Adhesion of foreign materials to the sensor chip 3 or IR filter 16 causes failure in an image taken and displayed by the camera module and lowers the production yield of the camera module.
In this Embodiment, the hole 52 is formed in the lens-barrel 4 as described above. Even if the air (gas) in the lens-barrel 4 (housing portion 4e thereof) is expanded by heating during the baking treatment of the bonding material 53, the expanded air passes through the hole 52 and is discharged (released) outside of the lens-barrel 4 (housing portion 4e thereof). This makes it possible to prevent air expanded that has in the lens-barrel 4 from passing from between the adhesive surface 4b of the lens-barrel 4 and the surface 2a of the wiring substrate 2c, and it also will prevent the bonding material 53 from attaching to the terminal portion 24 disposed in the outside vicinity region of the lens-barrel 4 over the surface 2a of the wiring substrate 2c. Therefore, the reliability of electric connection between the flexible substrate 21 and the terminal portion 24 can be improved, and the production yield of the camera module can also be improved. Moreover, in this Embodiment, the air which has expanded in the lens-barrel 4 (housing portion 4e thereof) is discharged to the outside of the lens-barrel 4 from the hole 52 so that formation of a gap between the adhesive surface 4b of the lens-barrel 4 and the surface 2a of the wiring substrate 2c can be prevented. Invasion of foreign materials in the lens-barrel 4 and adhesion of them to the sensor chip 3 or IR filter 16 in subsequent manufacturing steps can also be prevented. This leads to improvement in the production yield of the camera module.
After the lens-barrel 4 is fixed to the wiring substrate 2c by baking treatment of the bonding material 53, the hole 52 is filled with a bonding material (adhesive) 71 or the like.
As the bonding material 71 to fill the hole 52 of the lens-barrel 4, use of a cold setting bonding material (adhesive) or UV-curing bonding material (adhesive) is preferred. The hole 52 can be filled with such material without heat treatment, which makes it possible to prevent the passage of the air that has expanded in the lens-barrel 4 (housing portion 4e thereof) which will otherwise occur due to the heating, while filling the hole 52 and hermetically sealing the housing portion 4e of the lens-barrel 4. Since the hole 52 is filled, invasion of foreign materials in the lens-barrel 4 and adhesion of such foreign materials to the sensor chip 3 or IR filter 16 in subsequent manufacturing steps can be prevented, resulting in improvement of the production yield of the camera module. As the bonding material 71, use of a bonding material (for example, acrylic) having a water permeability lower than that of a silicon-based material is more preferred. Examples of the bonding material (adhesive) having a low water permeability include epoxy-based bonding materials (adhesives), as well as acrylic bonding materials (adhesives). Use of an epoxy-based bonding material, however, requires high-temperature heat treatment for setting. This high-temperature heat treatment may cause adhesion of the bonding material 53, which has scattered owing to the passage of the air that has expanded in the lens-barrel 4 (housing portion 4e thereof) due to the high temperature heat treatment, to the terminal portion 24 disposed in the outside vicinity region of the lens-barrel 4 over the surface 2a of the wiring substrate 2c. This suggests that a bonding material which needs heat setting treatment is not preferred, even if it has a low water permeability.
Bonding of the adhesive surface 4b of the lens-barrel 4 to the wiring substrate 2c with a cold setting bonding material (in other words, use of a cold setting bonding material as the bonding material 53) can be considered. Use of a cold setting type bonding material as the bonding material 53 for adhesion of the lens-barrel 4 causes a marked deterioration in the working efficiency in the application of the bonding material to the adhesive surface 4b of the lens-barrel 4, because it should be applied uniformly all over the adhesive surface 4b of the lens-barrel 4 by using a mask or the like. In this embodiment, on the other hand, the adhesive surface 4b of the lens-barrel 4 is bonded to the wiring substrate 2c with the thermosetting bonding material 53, so that the working efficiency in the application of the bonding material 53 to the adhesive surface 4b of the lens-barrel 4 can be improved. Moreover, in this embodiment, the hole 52 in the lens-barrel 4 can be made relatively small, but sufficiently large to permit discharge (exhaust) of a gas (air) therefrom. Therefore, the hole 52 can be filled easily with the bonding material 71; and, even if a cold setting bonding material, a UV-curing bonding material or a bonding material (for example, acrylic) having a lower water permeability than that of a silicon-based material is used, the working efficiency to fill the hole 52 hardly lowers.
If the size (for example, 0.9 mm in diameter) of the hole 52 on the outer surface side of the lens-barrel 4 is made greater than that (for example, 0.3 mm in diameter) of the hole 52 on the inner surface side of the lens-barrel 4, as illustrated in
In this Embodiment, the hole 52 serving as a vent hole (a hole for discharge) is disposed outside of the cylinder (cylindrical portion, head 4a) of the lens-barrel 4, as illustrated in
In the lens-barrel 4 as illustrated in
In this Embodiment, as will be described later, dicing treatment of wiring substrate 2c is carried out after adhesion of a protective film 81 to the head 4a of the lens-barrel 4. Even if the notch portion 52a or hole 52b is formed as a vent hole in the cylinder (in the head 4a) of the lens-barrel 4, as illustrated in FIGS. 34 to 37, foreign materials (dust and the like) do not enter in the lens-barrel 4 (housing portion 4e thereof), passing through the notch portion 52a or hole 52b during the dicing treatment of the wiring substrate 2c. Moreover, in the event that dust enters the cylinder in the head 4a, the notch portion 52a prevents easy arrival of dust onto the surface of the sensor chip 3. By the formation of the notch portion 52a, adhesion of dust to the surface of the sensor chip 3 can be suppressed further. After removal of the protective film 81, lens holder 5 is attached (installed) to the head 4a of the lens-barrel 4, while keeping the inside of the lens-barrel 4 clean. Invasion of foreign materials inside of the lens-barrel 4 can be substantially prevented by the attachment of the lens holder 5. After the lens holder 5 is attached, there is no more than a small possibility of foreign materials (dust) entering into the lens-barrel 4 (housing portion 4e thereof), passing through the notch portion 52a or hole 52b. It becomes sometimes unnecessary to fill the notch portion 52a or hole 52b with the bonding material 71 when the sensor chip 3 has a high durability against moisture (water). In such a case, the lens holder 5 can be installed onto to the head 4a of the lens-barrel 4 without filling the notch portion 52a or hole 52b, in other words, with the notch or hole open. This makes it possible to reduce the number of manufacturing steps.
When the partition plate 4c of the lens-barrel 4 has an extra space to make the hole 52b therein, the hole 52b as illustrated in
After a plurality of lens-barrels 4 are bonded to the surface 2a of the wiring substrate 2c in the above-described manner, a protective film (protective tape) 81 is adhered to the head 4a of the lens-barrel 4, which is to be a portion on which the lens holder 5 is loaded, in order to block the opening portion (upper opening portion) of the head 4a of each lens-barrel 4.
One example of the method of attaching the protective film 81 to the lens-barrel 4 will be described next. FIGS. 40 to 46 are diagrams illustrating the step of attaching the protective film 81 in this embodiment.
By using a protective film attaching jig set as illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
After the evacuation 87a of the vacuum piping system 85a is stopped, the wiring substrate 2c having the lens-barrel 4 bonded thereto is lifted, as illustrated in
Unlike this Embodiment, when the protective film 81 is adhered individually to each of the plurality of lens-barrels 4 bonded to the wiring substrate 2c, the manufacturing time increases and the working efficiency lowers. In this embodiment, on the other hand, the protective film 81 is adhered collectively to the plurality of lens-barrels 4 bonded to the wiring substrate 2c, so that the manufacturing time is reduced and the working efficiency can be improved.
After the protective film 81 is attached to the lens-barrel 4 as described above, the wiring substrate 2c is subjected to full dicing treatment, as illustrated in
Another method which can be considered is the use of an adhesive (bonding material) for fixing the lens-barrel 4 to the lens holder 5. When a one-component cold setting adhesive is used, the binding (adhesive) strength is relatively weak and it is not easy to maintain an adequate torque strength. A two-component cold setting adhesive, on the other hand, has a higher adhesive strength, but a low working efficiency. Further, it deteriorates the working environment by an undesirable odor. In addition, the adhesive sets as soon as two parts are mixed, which disturbs uniform application. When a thermosetting adhesive is used, heat upon setting may deform the lens 6 in the lens holder 5. Deformation of the lens 6 lowers the reliability and the production yield of the camera module.
In this Embodiment, the lens-barrel 4 and lens holder 5 are fixed by thermal welding. This makes it possible to heighten the bonding strength between the lens-barrel 4 and lens holder 5 and, therefore, to maintain a high torque strength. In the case where the lens holder 5 does not fit very well with the lens-barrel 4, they can be fixed firmly. This method has a high working efficiency, facilitates automatic fixing treatment of the lens holder 5 to the lens-barrel 4 and enables reduction in the number of steps and a shortening of the manufacturing time, because the lens-barrel 4 and lens holder 5 can be thermally welded by pressing the metal rod 111 against the lens-barrel. The lens 6 in the lens holder 5 does not change its shape by heating, because the lens-barrel 4 and lens holder 5 are thermally welded by partial heating. This method therefore contributes to an improvement in the reliability of the camera module and an improvement in the production yield. In addition, the working environment can be improved without emission of an odor of the adhesive.
In such a manner, the camera module 1 of this embodiment is manufactured (completed).
The camera module 1b of this Embodiment has a similar constitution to that of the camera module of Embodiment 1, except that the lens-barrel 4 and lens holder 5 are replaced with a lens-barrel 124 and a lens holder 125, respectively. Description on the constitution other than the lens-barrel 124 and lens holder 125 will be omitted.
The lens-barrel 124 and lens holder 125 can be formed by a similar material to that employed for the lens-barrel 4 and lens holder 5 of Embodiment 1, for example, a resin material, such as PBT (polybutylene terephthalate) or plastic material (insulating material). Similar to the lens-barrel 4, the lens-barrel 124 is bonded to the surface 2a of the wiring substrate 2 so as to cover the sensor chip 3, and the adhesive surface 4b which is the bottom surface on the side of the foot 4d of the lens-barrel 124 is bonded (adhered) to the surface 2a of the wiring substrate 2 by a bonding material.
In the lens-barrel 4 of Embodiment 1, the inner wall (inner circumference surface) of the cylindrical head 4a is threaded, while in this Embodiment, the outer wall (outer circumference surface) of the cylindrical head 4a of the lens-barrel 124 is threaded. In short, the head 4a of the lens-barrel 124 has an external thread (male thread) structure. Except for this, the lens-barrel 124 has a similar structure to the lens-barrel 4.
The lens holder 125 is installed to the head 4a of the lens-barrel 124 so as to block the opening of the head 4a of the lens-barrel 124. In Embodiment 1, the outer wall of the lower portion of the lens holder 5 (outer circumference surface of the cylindrical portion) is threaded, while in this Embodiment, the inner wall (inner circumference surface) of the cylindrical portion lens holder 125a of the lens holder 125 is threaded. In short, the lens holder 125 has an internal thread (female thread) structure.
The outer wall (outer circumference surface) of the head 4a of the lens-barrel 124 and inner wall (inner circumference surface) of the cylindrical portion 125a of the lens holder 125 are each threaded. The lens holder 125 is therefore attached to the lens-barrel 124 by turning the lens holder 125 to fit these threads with each other and screwing a portion of the head 4a of the lens-barrel 124 into the opening of the lens holder 125. As in Embodiment 1, the lens-barrel 124 and lens holder 125 are fixed by partially heating the side surface of the cylindrical portion 125a of the lens holder 125 to weld a portion of the cylindrical portion 125a of the lens holder 125 and a portion of the head 4a of the lens-barrel 124.
The lens holder 125 has, inside of the cylindrical portion 125a thereof, another cylindrical portion (cylinder for preventing invasion of foreign materials) 125b. This cylindrical portion 125b is located inside of the head 4a of the lens-barrel 124 with the lens holder 125 being attached thereto. When the lens holder 125 is attached to the lens-barrel 124, the head 4a of the lens-barrel 124 enters between the cylindrical portion 125a of the lens holder 125 and the cylindrical portion 125b inside thereof. A holding member 17 made of, for example, copper is connected to the cylindrical portion 125b, and by use of this holding member 17, the lens 6 is fixed or retained in the lens holder 125 by the holding member 17. Light outside of the camera module 1b is collected by the lens 6, passes through the IR filter 16 and is irradiated to the sensor chip 3.
In focus adjustment, there is a possibility of foreign materials (dust) appearing from the threads (a fitted portion of the threads of the lens-barrel and lens holder) when the lens holder is turned. These foreign materials fall inside of the lens-barrel, adhere to the IR filter 16, and become a cause for stain failure (failure such as dim stain) in the image taken and displayed by the camera module.
In this Embodiment, the outer wall of the head 4a of the lens-barrel 124 and the inner wall of the cylindrical portion 125a of the lens holder 125 are each threaded and the lens holder 125 is fitted in the lens-barrel 124. In other words, the head 4a of the lens-barrel 124 has an external thread (male thread) structure. Even if foreign materials appear from the threads of the lens-barrel 124 and lens holder 125, they do not fall inside of the lens-barrel 124, but fall outside thereof. It is therefore possible to suppress or prevent the foreign materials from attaching to the IR filter 16, and to prevent generation of stain failure in the image taken and displayed by the camera module. In addition, the production yield of the camera module can be improved.
Also in this Embodiment, after the lens holder 125 is installed in the lens-barrel 124 and focusing is performed, the lens holder 125 is fixed to the lens-barrel 124 by thermal welding similar to Embodiment 1 as described above. For example, by pressing a hot metal rod 111, as described in conjunction with Embodiment 1, against the side surface of the cylindrical portion 125a of the lens holder 125, the lens holder 125 and the lens-barrel 124 are thermally welded and the lens holder 125 is fixed to the lens-barrel 124.
In this Embodiment, invasion of foreign materials (dust) into the lens-barrel 124 can be prevented completely, because the cylindrical portion 125b is disposed in the lens holder 125 so as to be located inward of the head 4a of the lens-barrel 124. Upon fixing of the lens holder 125 to the lens-barrel 124 by thermal welding, heat is shielded by the cylindrical portion 125b so that conduction of heat to the lens 6 can be inhibited. Heat conduction to the lens 6 may occur via the holding member 17; however, in this Embodiment, the holding member 17 is connected not to the outside cylindrical portion 125a which is to be thermally welded, but to the inner cylindrical portion 125b, so that heating of the lens 6 can be prevented. Thermal damage to the lens 6 can therefore be reduced and deformation of the lens 6 can be prevented more severely, resulting in further improvement in the production yield of the camera module.
A solid state image sensing device of this third Embodiment, for example, a camera module 1c, is obtained by covering the camera module 1 of Embodiment 1 with metal covers (conductor covers) 131 and 132.
The camera module 1 is covered with the metal covers 131 and 132 after the lens holder 5 is fixed to the lens-barrel 4. As illustrated in
The metal cover 131 has a clamp 131a which has been hooked on the side surface of the metal cover with a steel plate, while the metal cover 132 has, on the side surface thereof, an opening portion 132a. When the camera module 1 is covered with the metal covers 131 and 132, the clamp 131a of the metal cover 131 is fitted in the opening portion 132a of the metal cover 132, whereby the metal cover 131 and metal cover 132 can be fixed together.
The metal cover 131 has, on the top thereof, an opening portion 131c, and the lens holder 5 (and the head 4a of the lens-barrel 4) can protrude from this opening 131c when the metal cover 131 is placed over the camera module 1. In addition, the metal cover 131 has a thin-plate (foil) portion 131b, and this thin plate portion 131b of the metal cover 131 extends over the flexible substrate 21 protruding from the metal covers 131 and 132 when the camera module 1 is covered with the metal covers 131 and 132. After the camera module 1 is covered with the metal covers 131 and 132, the thin plate portion 131b is electrically connected to the GND wiring pattern (wiring pattern to be connected to a ground potential, not illustrated) of the flexible substrate 21 with solder 133 or the like, whereby the metal covers 131 and 132 are electrically connected to the GND wiring pattern of the flexible substrate 21. In the above-described manner, the camera module 1c of this Embodiment is available. As another embodiment, the camera module 1 may be covered with a metal tape.
In the camera module 1c according to this Embodiment, its circumference (surface), except for a portion constituted by the lens holder 5 and a portion of the flexible substrate 21, is covered with a conductor, here by metal covers 131 and 132. In other words, the wiring substrate 2, lens-barrel 4 and the exposed surface of the sealing resin 10, and the upper surface (a portion) of the flexible substrate 21 are covered with the metal covers 131 and 132. These metal covers 131 and 132 are electrically connected to the GND wiring pattern of the flexible substrate 21. When using the camera module 1c mounted on an electronic apparatus (such as cellular phone), the metal covers 131 and 132 can be used, for example, as a ground potential. They can therefore prevent the high frequency wave (noise) in the camera module 1c from adversely affecting the peripheral devices outside of the camera module 1c and can also prevent the high frequency wave (noise) of the peripheral devices outside of the camera module 1c from adversely affecting the internal circuit of the camera module 1c. Therefore, camera module 1c having such covers has an improved performance.
FIGS. 65 to 67 are views illustrating one example of the mounting of the camera module 1c of this Embodiment on a substrate (mounting substrate, external substrate, wiring substrate) 141.
As illustrated in FIGS. 65 to 68, the substrate 141 has a metal case 142 mounted thereon. The metal case 142 is made of a conductor material, such as metal, and has a shape permitting insertion therein of the camera module 1c from the direction of the arrow 140. When the camera module 1c is inserted into the metal case 142, the lens holder 5 protrudes from the notch portion 142a disposed on the upper surface of the metal case 142, whereby the position of the camera module 1c is determined. The metal case 142 has a protrusion 144 made of a conductor material (for example, a conductor material similar to that used for the metal case 142) and this protrusion 144 is electrically connected to the ground pattern (not illustrated) of the substrate 141 via a conductive bonding material 145, such as solder. The metal case 142 is therefore electrically connected to the ground pattern of the substrate 141. Into the metal case 142 mounted (bonded) onto the substrate 141 via the bonding material 145, the camera module 1c is inserted from the direction of an arrow 140, and a connector 150 (corresponding to the connector 25) disposed on the flexible substrate 21 is connected to a connector 143 disposed on the substrate 141. For example, the connector 150 is inserted into the connector 143 to connect the connector 150 and the connector 143. The connector 143 is electrically connected to a wiring pattern (not illustrated) formed over the substrate 141. The connector 150, serving as an external terminal of the camera module 1c, is electrically connected to the wiring pattern of the substrate 141 via the connector 143.
The metal covers 131 and 132 of the camera module 1c are electrically connected to the GND wiring pattern of the flexible substrate 21 and are electrically connected to the ground pattern over the substrate 141 via the connector 150 and connector 143. By inserting the camera module 1c into the metal case 142 that is electrically connected to the ground pattern of the substrate 141, the metal covers 131 and 132 are electrically connected to the ground pattern of the substrate 141 via the metal case 142 and bonding material 145. This therefore makes it possible to connect the metal covers 131 and 132 covering the camera module to the ground potential and, moreover, to shorten the wiring length from the metal covers 131 and 132 to the ground pattern of the substrate 141. Accordingly, it is possible to appropriately prevent high frequency wave (noise) in the camera module 1c from adversely affecting the peripheral devices outside the camera module 1c and to accurately prevent the high frequency wave (noise) of peripheral devices outside the camera module 1c from adversely affecting the internal circuit of the camera module 1c. Thus, the camera module 1c is able to have an improved performance.
This Embodiment can be applied to Embodiment 2, and the camera module 1b can be covered with the metal covers 131 and 132. In this case, similar advantages to those described above are available.
The invention made by the present inventors has been described specifically based on its embodiments. It should, however, be born in mind that the present invention is not limited to these embodiments, and it is needless to say that the invention can be modified within a range not departing from the scope of the invention.
In the above description, the invention made by the present inventors was applied to a camera module using a CMOS image sensor. However, the present invention is not limited to the application, but can be applied to other camera modules, such as camera modules using a CCD (Charge Coupled Device) image sensor.
The present invention is effective when applied to a solid state image sensing device of the type used for mobile communication devices, such as cellular phones, and to the manufacturing techniques thereof.
Number | Date | Country | Kind |
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2003-329700 | Sep 2003 | JP | national |