Image pickup apparatus, semiconductor apparatus, and image pickup unit

An image pickup apparatus includes: an image pickup chip including a light receiving section and electrode pads, on a first main face, and a plurality of connection electrodes, each of which is connected to each of the electrode pads via each of a plurality of through-hole interconnections, on a second main face; a transparent cover glass having a larger plan-view dimension than the image pickup chip; a transparent adhesive layer that bonds the first main face of the image pickup chip and the cover glass; and a sealing member that covers a side face of the image pickup chip and a side face of the adhesive layer, and is made of an insulating material having a same plan-view dimension as the cover glass.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image pickup apparatus, a semiconductor apparatus, and an image pickup unit produced by a WL-CSP method.

2. Description of the Related Art

A chip size package (CSP) method has been used for downsizing semiconductor apparatuses. In the CSP, in a semiconductor chip where a semiconductor circuit section is formed on a first main face, a through-hole interconnection is formed up to a second main face, and an external connection terminal on the second main face is connected to an interconnection board.

Here, in a small image pickup apparatus, a transparent support member that protects a light receiving section that is the semiconductor circuit section is joined to a first main face of an image pickup chip on which the light receiving section is formed. A wafer level chip size package (WL-CSP) method has been used for collectively fabricating a plurality of image pickup apparatuses. In the WL-CSP, an image pickup chip substrate on which a plurality of light receiving sections are formed, and a transparent support substrate are subjected to machining such as formation of through-hole interconnections in a joined wafer state in which the image pickup chip substrate and the transparent support substrate are bonded via an adhesive layer. After that, the joined wafer is individualized into individual image pickup apparatuses.

Note that Japanese Patent Application Laid-Open Publication No. 2011-243596 discloses a method for producing a package component by a CSP method in which semiconductor chips mounted on a mounting face of a silicon wafer are sealed by a sealing resin, and the silicon wafer is then polished or the like from an opposite face to the mounting face, and further individualized into individual package components.

That is, in the above production method, the semiconductor chips are not machined, but the silicon wafer is machined to become an interposer for the semiconductor chips.

Since the image pickup apparatus produced by the WL-CSP method is ultra-small, the image pickup apparatus is particularly suited to be disposed at a distal end portion of an insertion section of an endoscope.

SUMMARY OF THE INVENTION

An image pickup apparatus of an embodiment of the present invention includes: an image pickup chip including a light receiving section and electrode pads formed around the light receiving section, on a first main face, and a plurality of connection electrodes, each of which is connected to each of the electrode pads via each of a plurality of through-hole interconnections, on a second main face; a transparent support substrate section having a larger plan-view dimension than the image pickup chip; a transparent adhesive layer that bonds the first main face of the image pickup chip and the support substrate section; and a sealing member that covers a side face of the image pickup chip and a side face of the adhesive layer, and is made of an insulating material having a same plan-view dimension as the support substrate section.

Also, a semiconductor apparatus of another embodiment includes: a semiconductor chip including a semiconductor circuit section and electrode pads formed around the semiconductor circuit section, on a first main face, and a plurality of connection electrodes, each of which is connected to each of the electrode pads via each of a plurality of through-hole interconnections, on a second main face; a support substrate section having a larger plan-view dimension than the semiconductor chip; an adhesive layer that bonds the first main face of the semiconductor chip and the support substrate section; and a sealing member that covers a side face of the semiconductor chip and a side face of the adhesive layer, and is made of an insulating material having a same plan-view dimension as the support substrate section.

An image pickup unit of yet another embodiment includes: an image pickup apparatus including an image pickup chip including a light receiving section and electrode pads connected to the light receiving section, on a first main face, and a plurality of connection electrodes, each of which is connected to each of the electrode pads via each of a plurality of through-hole interconnections, on a second main face, a transparent support substrate section having a larger plan-view dimension than the image pickup chip, a transparent adhesive layer that bonds the first main face of the image pickup chip and the support substrate section, and a first sealing member that covers a side face of the image pickup chip and a side face of the adhesive layer, and is made of an insulating material having a same plan-view dimension as the support substrate section; a lens unit that forms an object image on the light receiving section; a signal cable that is connected to the connection electrodes via an interconnection board; and a shield case in which the image pickup apparatus and the interconnection board are sealed by a second sealing member and accommodated, and that is made of a metal material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown inFIG. 1, in an image pickup apparatus10that is a semiconductor apparatus, an image pickup chip (imager chip)30, and a cover glass20that is a support substrate section (transparent flat plate section) are bonded via an adhesive layer41made of a transparent resin. A light receiving section31that is a semiconductor circuit section is formed on a first main face30SA of the image pickup chip30, and a plurality of electrode pads32connected to the light receiving section31by an interconnection (not shown) are further formed around the light receiving section31of the first main face30SA. An electrode pad32is connected to an external connection electrode34and an external connection terminal35on a second main face30SB via a through-hole interconnection33. That is, the plurality of electrode pads32supply electricity to the light receiving section31, and transmit and receive input and output signals to and from the light receiving section31. Moreover, outer peripheral portions of the image pickup chip30and outer peripheral portions of the adhesive layer41are covered with a sealing member42with no gap therebetween.

An insulating layer43covers and protects a surface of the sealing member42and the second main face30SB of the image pickup chip30as well as covering a wall face of a through-hole via to effect insulation between silicon as a base material of the image pickup chip30and the through-hole interconnection33. Furthermore, a region of the second main face30SB other than an external connection terminal formation region is covered with the insulating layer43and a protective layer44.

That is, in the image pickup apparatus10, a plan-view dimension (outer dimension) of the cover glass20is larger than a plan-view dimension (outer dimension) of the image pickup chip30. This is because the image pickup apparatus10is fabricated by cutting (individualizing) a joined wafer40W where a plurality of image pickup chips30are bonded to a glass wafer20W, which is a transparent support substrate that becomes the cover glass20, away from each other by a predetermined length via the adhesive layer41as shown inFIG. 2. As described below, on the glass wafer20W, an alignment mark21for arranging each of the image pickup chips30at a predetermined position is formed. That is, since the glass wafer20W is transparent, the alignment mark (first alignment mark)21and an alignment mark (second alignment mark)36(seeFIG. 5) on the image pickup chip30can be aligned with each other from an opposite face to a face where the alignment mark21is formed.

Next, a method for producing the image pickup apparatus10of the embodiment is described in detail based on flowcharts inFIGS. 3A and 3B.

<Step10> Glass Wafer Fabricating Process

As shown inFIG. 4, the alignment marks21for arranging the image pickup chips30at predetermined positions are formed on the glass wafer20W that is the transparent support substrate. Note that an image pickup chip arrangement region30S is indicated by a broken line for the sake of description inFIG. 4. The glass wafer20W that is cut to become the cover glass20only needs to be transparent in a wavelength band of light for image pickup. For example, borosilicate glass, quartz glass, or single crystal sapphire is used.

Note that alignment marks22and alignment marks23are formed at a same time as formation of the alignment marks21. The alignment marks22are used for dicing at a time of individualization, and the alignment marks23are used for machining such as formation of the through-hole interconnection33in the image pickup chip30. The alignment marks21and the like are formed by, for example, performing patterning by photolithography after forming a metal layer of Al or the like on an entire face. It is preferable that two alignment marks are provided for one time of positioning processing for the respective alignment marks so as to perform accurate positioning. Note that the alignment marks21and the like may be also formed by partially etching the glass wafer20W.

Note that a back face of the glass wafer20W (the opposite face to the face where the alignment marks21are formed), which is not machined in following processes, may be covered with a photoresist or the like to be protected.

<Step11> Image Pickup Chip Fabricating Process

The plurality of light receiving sections31that are the semiconductor circuit sections, the plurality of electrode pads32connected to each of the light receiving sections31, and the plurality of alignment marks36are formed on the first main face30SA of a semiconductor wafer such as a silicon wafer by a known semiconductor process, so that an image pickup chip substrate30W (seeFIG. 2) is fabricated. By cutting and individualizing the image pickup chip substrate (semiconductor chip substrate)30W, the plurality of image pickup chips (semiconductor chips)30shown inFIG. 5are fabricated.

Sizes of the image pickup chip substrate and the glass wafer20W are selected according to available production equipment or the like depending on a form and specifications etc. of the image pickup apparatus to be produced. Also, the image pickup chip substrate and the glass wafer20W may be set to different sizes. For example, even when the image pickup chips are formed from a substrate having a large diameter of 12-inch (300-mm)φ, or from a still larger substrate, the individualized image pickup chips30are re-arrayed (bonded) on the glass wafer20W of 8-inch (200-mm)φ, and subjected to machining. Accordingly, it becomes possible to produce the image pickup apparatus by equipment for 8-inch (200-mm)φ without using equipment or the like compatible with a large-diameter wafer. Moreover, a substrate and a wafer of different shapes, for example, the image pickup chip substrate of 8-inch (200-mm)φ and the glass wafer20W of 6-inch (150-mm) squares, may be also used depending on equipment and apparatuses, etc. As described above, since the image pickup chip substrate and the glass wafer20W of suitable sizes or shapes for available production equipment or the like (a production apparatus, a jig and a tool, etc.) can be used, the image pickup apparatus can be produced by effectively utilizing existing equipment or the like.

In following processes, only the image pickup chips30determined as non-defective products in an inspection process are used. That is, “defective chips” other than the non-defective products are not used in the following processes. Thus, even when a yield rate of the image pickup chips30of the image pickup chip substrate30W is low, a decrease in yield rate of the image pickup chips obtained by re-arraying and re-machining the image pickup chips is not caused. Note that it is preferable to perform an inspection for determining defectiveness of the image pickup chips on the image pickup chips30in a state of the substrate30W in view of work efficiency although the inspection may be performed on each of the individual image pickup chips30in an individualized state.

The alignment marks36correspond to the alignment marks21on the glass wafer20W. As shown inFIG. 5, the alignment marks36are preferably formed respectively on outer peripheral portions facing each other with a center of the image pickup chip30therebetween. By previously forming the alignment marks on the glass wafer20W and the image pickup chip30, the image pickup chip30can be automatically placed with high precision by using a mounting apparatus.

Also, a step portion37is formed in the outer peripheral portions of the first main face30SA of the image pickup chip30. The step portion37is fabricated by dicing the image pickup chip substrate30W by step cutting. The image pickup chip30with the step portion37can reduce a length L with an adjacent chip so as to prevent spread (a fillet) of an adhesive41L to an outer side of the image pickup chip30when bonded to the glass wafer20W. A micro lens group may be also disposed on the light receiving section31.

As shown inFIG. 6A, the plurality of image pickup chips30are bonded to the glass wafer20W away from each other by the predetermined length L to fabricate the joined wafer40W. That is, the plurality of image pickup chips30formed on the image pickup chip substrate30W on predetermined array conditions are then re-arrayed on the glass wafer20W after cutting.

The length L needs to be longer than a thickness of a dicing blade used in a dicing process described below. However, if the length L is too long, the number of image pickup apparatuses that can be fabricated from the single glass wafer20W is decreased. At a same time, the sealing member has a larger volume in a sealing member filling process described below, and a curing shrinkage stress becomes larger, so that a crack is easily generated. Therefore, the length L is preferably 15 μm or more and 500 μm or less, which is slightly longer than the thickness of the dicing blade.

Also, by setting the length L to a constant value among all of the image pickup chips30, workability can be improved, and uniform filling of the sealing member is enabled in the sealing member filling process described below. The crack caused by unevenness of the curing shrinkage stress can be thereby prevented.

For example, the adhesive41L in a liquid form is first applied in an appropriate amount to five positions of the image pickup chip arrangement region30S of the glass wafer20W. The image pickup chip arrangement region30S can be grasped by the two alignment marks21arranged on a diagonal line. For example, a dispensing method of pushing out a solution from a distal-end nozzle of a dispenser and applying the solution is used as an application method.

As the adhesive41L, a BCB (benzocyclobutene) resin, an epoxy-based resin, or a silicone-based resin etc., which satisfies such properties that the adhesive has high transparency (for example, a transmittance at visible wavelengths is 90% or more), has high adhesive strength, and is not deteriorated by heat or the like in subsequent processes, is used.

The image pickup chip30is then bonded to the glass wafer20W in a state in which the first alignment marks21on the glass wafer20W and the second alignment marks36on the first main face30SA of the image pickup chip30are aligned with each other by using, for example, a flip chip bonder. The first alignment marks21and the second alignment marks36are set so as to be easily aligned with each other. For example, the first alignment mark21has a cross shape as shown inFIG. 4, and the second alignment mark36is composed of four squares as shown inFIG. 5.

Note that a reference mark may be previously formed on the glass wafer20W without forming the alignment marks exclusive for the respective image pickup chips, and the image pickup chips30may be arranged at a predetermined pitch based on the reference mark. A throughput can be raised by using the above method. Also, alignment may be performed by using a pattern of the electrode pads32or the like formed on the image pickup chip30instead of the second alignment marks36.

The liquid adhesive41L is cured in a state in which the alignment marks are aligned with each other, and becomes the adhesive layer41. By completely curing the liquid adhesive41L while pressing the second main face of the image pickup chip at a predetermined pressure by a wafer-shaped pressing jig, parallelism between the main face of the image pickup chip and the main face of the glass wafer20W is increased.

As a method for curing the adhesive41L, any of a thermal curing method, a UV curing method, the UV curing method+the thermal curing method, the UV curing method+a moisture curing method, and a room temperature curing method etc. may be employed depending on the resin as long as desired properties are satisfied. By using a flip chip bonder including means for curing the adhesive41L, such as a heating section or an UV irradiation section, the arrangement of the image pickup chip30at a predetermined position, and the curing of the adhesive41L can be performed at a same time.

Note that attention needs to be paid when the adhesive41L where voids are easily generated by rapid curing is used although the adhesive41L may be completely cured by the flip chip bonder. In this case, it is preferable that, for example, when the adhesive41L is cured by the flip chip bonder, the adhesive41L is semi-cured to an extent where the image pickup chip30disposed at a predetermined position does not move to cause displacement, and after the plurality of image pickup chips30are disposed on the glass wafer20W, the adhesive41L is completely cured at a time and formed into the adhesive layer41.

<Step S13> Sealing Member Filling Process

As shown inFIG. 6B, a sealing resin42L in a liquid form that is filled into a gap between the plurality of image pickup chips30disposed on the glass wafer20W by, for example, a dispensing method is cured to become the sealing member42. The sealing resin42L may be also poured into the gap instead of the dispensing method.

By setting the arrangement length L between the plurality of image pickup chips30to 15 μm or more and 500 μm or less, the sealing member can be filled into the gap between the plurality of image pickup chips30by a capillary tube phenomenon. Note that a region where vertexes of the plurality of image pickup chips30face each other tends to have a small height (thickness) when filled with the sealing resin42L. Therefore, after the sealing resin is cured once, the sealing resin may be applied again only to the portion where the vertexes of the plurality of image pickup chips30face each other.

The sealing member42preferably has a low moisture vapor transmission rate so as to improve humidity resistance of the image pickup apparatus10, and is difficult to deteriorate by heat or plasma in subsequent processes. For example, a BCB resin or polyimide is used. Note that the sealing member42may be made of a same material as or a different material from the adhesive layer41.

Also, the sealing member42preferably has a function as a light shielding member that prevents entrance of external light into the light receiving section. To this end, even when the sealing member42is made of the same resin as the adhesive layer41, the resin is preferably used by mixing a light shielding material such as a dye or a black pigment therein. Note that a non-conductive material is used when the pigment or the like is used since the sealing member42needs to be an insulator.

A thickness of the sealing member42, namely, a height to be filled only needs to be larger than a thickness of the image pickup chip30after thinning in step S14. That is, it is not necessary to completely fill the space between the plurality of image pickup chips30with the sealing member42before the thinning machining Conversely, the sealing member42may protrude from the space between the image pickup chips30.

Note that it is not preferable to perform rapid heating or rapid cooling in the curing of the sealing resin42L in order to prevent the crack occurrence due to the shrinkage stress when the sealing resin42L is cured. Also, it is preferable that the sealing resin42L is defoamed in vacuum before curing, or is cured in vacuum in order to prevent the occurrence of voids.

Note that the sealing member42is not limited to the cured liquid resin. For example, a sheet-like resin member may be cured after filling the space between the image pickup chips30wile embedding the image pickup chips30by vacuum hot pressing or vacuum laminating

<Step S14> Image Pickup Chip Machining Process

An image pickup chip machining subroutine is shown inFIG. 3B.

As shown inFIG. 6C, the joined wafer40W is thinned, so that an image pickup chip bonded face (the second main face30SB) side is flattened. That is, a back grinding process and a CMP (chemical mechanical polishing) process are performed from the second main face30SB side.

In the back grinding process, a diamond wheel called a back grinding wheel is used. The CMP process is performed for reducing surface roughness of a surface grinded in the back grinding process.

Note that when a surface of the joined wafer40W has large irregularities after being filled with the sealing member, preprocessing by another means is preferably performed before the back grinding process. For example, as the preprocessing, the sealing member42protruding from the gap between the image pickup chips30is shaved by a blade.

Note that dishing, which forms a recess in a center portion of the surface of the sealing member42, may occur by the back grinding process and the CMP process. However, since the recessed portion is removed in the dicing process, there occurs no problem.

The second main face30SB of the image pickup chip30and the surface of the sealing member42on the joined wafer40W after thinning form a flat face. Therefore, a similar process to that of a normal semiconductor wafer can be performed on the thinned joined wafer40W.

That is, as shown inFIG. 6D, a through-hole via33S for forming the through-hole interconnection33that is connected to the electrode pad32formed on the first main face30SA of the image pickup chip30is formed by the normal semiconductor wafer process.

As shown inFIG. 6D, to form the through-hole via, an etching mask39having an opening in a region immediately above each of the electrode pads32is formed on the image pickup chips30and the sealing member42. The etching mask39also serves as a protective layer for protecting the image pickup chips30and the sealing member42from chemicals and plasma used in a subsequent process.

As the etching mask39, an inorganic film such as a silicon oxide film or a silicon nitride film, or an organic film such as a photoresist, polyimide, or BCB is used. When the inorganic film is used as the etching mask39, the inorganic film is formed by using plasma CVD or optical CVD. Since the film formation methods are performed at low temperature, no damage is caused on the semiconductor circuit section (the light receiving section31) or the like formed on the image pickup chip30. As a source gas when the silicon oxide film is formed, tetraethoxysilane (TEOS) or octamethylcyclotetrasiloxane (OMCTS) etc. is used. Also, as a source gas when the silicon nitride film is formed, a mixture gas such as SiH4+NH3, SiH2CL2+NH3, SiH4+N2, or SiH4+NH3+N2is used.

On the other hand, when the organic film is used as the etching mask39, the organic film is formed by spin coating, spray coating, or screen printing, etc.

To strip the etching mask39in a subsequent process, the etching mask39made of a different material from the sealing member42is used. For example, when the sealing member42is made of polyimide, for example, the silicon oxide film or the silicon nitride film is used as the etching mask39. Since the film formation can be performed at low temperature as the method for forming the etching mask39, and no damage is caused on the semiconductor circuit section or the like formed on the image pickup chip30, plasma CVD is preferably used.

Note that the alignment marks23for forming the through-hole interconnection, which are previously formed on the glass wafer20W, are used for alignment of a photo mask used when a patterning mask (not shown) for forming the opening in the etching mask39is formed.

When the silicon oxide film, the silicon nitride film, or a non-photosensitive resin is used as the etching mask39, the mask is etched with a photoresist with an opening pattern to form the opening. In the silicon oxide film or the like, dry etching using a fluorine-based gas such as CF4, CHF3, or C2F6is performed. On the other hand, when a photosensitive resin is used, the etching mask39with the opening can be formed by photolithography patterning.

The through-hole via33S is formed using the etching mask39by the normal semiconductor wafer process.

For example, the through-hole via33S reaching the electrode pad32is formed by wet etching using an alkali solution such as KOH or TMAH, or dry etching by an ICP-RIE method or the like.

The through-hole via33S formed by the wet etching has a tapered shape where an opening size in the first main face30SA is smaller than an opening size in the second main face30SB. This is because when the image pickup chip30is made of single crystal silicon (100), anisotropic etching is caused in which an etching rate in a <100> plane direction is relatively higher than an etching rate in a <111> plane direction.

Furthermore, in the etching of the through-hole via33S, side etching occurs in which the opening size in the second main face30SB becomes larger than an opening size in the etching mask39. Therefore, the opening size in the etching mask39is set to be smaller than a target opening size in the second main face30SB. In the through-hole via forming process, the etching mask39protects the sealing member42from the alkali solution.

Note that the through-hole via33S may be also formed by the dry etching such as ICP-RIE, or a physical machining method such as laser machining.

The etching mask39is stripped. As a stripping method, a removing method with high etch selectivity between the etching mask39and the sealing member42is selected. For example, when the sealing member42is made of polyimide and the etching mask39is the silicon oxide film, a wet stripping method using a fluorine-based solution such as BHF is used.

As shown inFIG. 6E, the insulating layer43is formed in which an opening is patterned in a bottom face of the through-hole via33S such that the electrode pad32is exposed with the second main face30SB of the image pickup chip30, the surface of the sealing member42, and a wall face of the through-hole via33S covered. An insulating material similar to that of the etching mask39is used for the insulating layer43. As a method for forming the insulating layer and a method for patterning the opening, a formation method similar to or different from that of the etching mask39may be employed.

Since the insulating layer43is not stripped in following processes, the insulating layer43protects the sealing member42in the following processes. For example, the insulating layer43protects the sealing member42from chemical treatment or plasma treatment during patterning in a through-hole interconnection forming process in step S25.

As shown inFIG. 6F, the through-hole interconnection33composed of a conductor is formed in an inner portion (the bottom face and the wall face) of the through-hole via33S. The through-hole interconnection33is formed by patterning after forming a conductive film of aluminum or copper etc. using a sputtering method or a deposition method. Note that a plating process may be used in the through-hole interconnection forming process.

<Step S26> External Connection Electrode Forming Process

After the etching mask39is removed, the external connection electrode34connected to the through-hole interconnection33is formed on the second main face30SB of the image pickup chip30. Note that the external connection electrode34may be also formed at a same time as the formation of the through-hole interconnection.

<Step S28> External Connection Terminal Forming Process

The projecting external connection terminal35for effecting electrical connection with outside is disposed on the external connection electrode34. A gold stud bump, or a solder ball etc. is used for the external connection terminal35.

A plurality of image pickup apparatuses10are fabricated from the single joined wafer40W by an individualizing process of cutting the joined wafer40W.

For cutting, a two-stage dicing method shown inFIGS. 6I and 6Jis preferable. That is, after the joined wafer40W is half-cut to about 10 to 200 μm from a surface of the glass wafer20W (an upper side in the drawings), the glass wafer20W is subjected to full-cut dicing, so that a crack occurrence due to a stress and stripping of the sealing member42can be prevented. Moreover, in the two-stage dicing method, a blade type (a bond material, an abrasive grain diameter, a degree of concentration) and machining conditions (a feed speed, a rotation speed) suitable for resin are used for dicing the sealing member42, and a blade type and machining conditions suitable for glass are used for dicing the glass wafer20W. A machining quality (resin burrs, chipping of glass, and delamination of a resin layer) can be thereby improved. Also, step cutting by which a step is formed in end portions of the individualized image pickup chips30may be performed by setting the blade for resin to a larger thickness than the blade for glass.

Also, the glass wafer20W may be subjected to full-cut dicing by blade dicing for glass or laser dicing, and thereby individualized after removing the sealing member42on a dicing line by laser dicing or etching.

In alignment of dicing, the alignment marks22firstly formed on the glass wafer20W are used. Note that, instead of the alignment marks22, an alignment mark for dicing may be formed on the second main face30SB of the image pickup chip30or on the sealing resin between the image pickup chips30in the through-hole interconnection forming process or the like.

In the production method of the embodiment, even when the image pickup chip substrate30W has a low yield rate of image pickup devices, the joined wafer40W is fabricated by using only the non-defective image pickup chips30. Therefore, the defective chip is not produced into the image pickup apparatus, so that the image pickup apparatus10can be produced at low cost, and productivity is high.

Also, in the production method of the embodiment, the image pickup apparatus can be produced by using the joined wafer40W with a predetermined diameter regardless of the diameter of the image pickup chip substrate30W. Since machining equipment compatible with a large diameter is unrequired, productivity is high.

Moreover, since the image pickup chip with a large thickness before being machined is bonded to the glass wafer20W, the image pickup chip is easily handled. That is, the image pickup chip that is thinned for forming the through-hole interconnection is easily damaged, and easily deformed by a stress during bonding or the like. However, in the production method of the embodiment, the image pickup chip in a thick state can be bonded to the glass wafer20W.

Also, since the support substrate is the transparent glass wafer20W, alignment using the alignment marks can be performed from the opposite face to the image pickup chip bonded face as shown inFIG. 2.

Furthermore, when the joined wafer40W is machined from the second main face30SB side by the wafer process, the sealing member42is covered with and protected by the etching mask39or the insulating layer43. Therefore, the sealing member42is not deteriorated, so that the highly-reliable image pickup apparatus can be produced by the production method of the image pickup apparatus of the embodiment.

Also, since the chip arrangement length is set to a constant value, it is easy to fill the sealing resin42L, thereby preventing the crack in the sealing resin42L. Thus, a production yield rate is high.

Moreover, the image pickup chip30and the sealing member42can be treated as a single wafer by the flattening machining for making the outer face of the image pickup chip30and the outer face of the sealing member42flush with each other by the CMP. Thus, the semiconductor wafer process can be performed on a chip-shaped component, and high-precision and high-density machining can be performed.

The image pickup apparatus10includes the image pickup chip30that is the semiconductor chip where the light receiving section31that is the semiconductor circuit section is formed on the first main face30SA, the cover glass20that is the support substrate section having a larger plan-view dimension than the image pickup chip30, the transparent adhesive layer41that bonds the first main face30SA of the image pickup chip30and the cover glass20, and the sealing member42that covers a side face of the image pickup chip30and a side face of the adhesive layer41, and is made of an insulating material having a same outer dimension (plan-view dimension) as the cover glass20.

In an image pickup apparatus fabricated by a conventional W-CSP method, a joined substrate obtained by joining a glass wafer and an image pickup device substrate is cut. Thus, an image pickup chip and a support substrate section have a same plan-view dimension (outer dimension). On the contrary, the side face of the image pickup chip30is covered with the sealing member42, and the image pickup chip30is not exposed outside. Moreover, the second main face30SB of the image pickup chip30is covered with the insulating layer43except for the external connection terminal35. That is, all the surfaces of the image pickup chip30are electrically insulated. Therefore, the image pickup apparatus10has excellent electrical insulating properties and humidity resistance.

Note that a functional member may be further added to the image pickup apparatus10of the above embodiment. For example, an objective lens unit may be joined to the opposite face to the face of the glass wafer20W where the image pickup chip30is bonded in alignment with the image pickup chip30. Also, a digital signal processor (DSP) chip for processing an image pickup signal may be joined to the second main face30SB of the image pickup chip30.

A backside irradiation-type image pickup apparatus may be also produced through processes of bonding an interconnection layer side of the image pickup chip30to the support substrate, filling the sealing resin into the gap between the image pickup chips30, thinning the image pickup chip30to about 3 μm to expose the light receiving section31, thereafter forming a color filter and a micro lens on the light receiving section31, and removing a silicon layer on the electrode to expose the electrode.

Also, the semiconductor chip is not limited to the image pickup chip, and any type, such as general semiconductor chips, various sensors or actuators, may be employed. The semiconductor apparatus to be produced is also not limited to the image pickup apparatus.

Since the image pickup apparatus of the above embodiment and modifications has high reliability while being ultra-small, the image pickup apparatus can be preferably used particularly as an image pickup apparatus disposed at a distal end portion of an electronic endoscope, or disposed in a capsule endoscope.

<Modification of the First Embodiment>

Next, image pickup apparatuses10A to10D of Modifications 1 to 4 of the image pickup apparatus10in the first embodiment of the present invention are described. Since the image pickup apparatuses10A to10D of the modifications are similar to the image pickup apparatus10of the embodiment and have the same effects, same constituent elements are assigned same reference numerals, and description is omitted.

As shown inFIG. 7, in the image pickup apparatus10A of the modification, an image pickup chip30A has a trapezoidal section. The electrode pad32on the first main face30SA and the external connection electrode34on the second main face30SB are connected by a side face interconnection33A formed on the side face of the image pickup chip30A. The side face of the image pickup chip30A is covered with the sealing member42.

It is easier to form the side face interconnection33A than the through silicon via (TSV) and the through-hole interconnection. Therefore, it is easier to produce the image pickup apparatus10A than the image pickup apparatus10.

Next, in the image pickup apparatus10B of Modification 2 shown inFIG. 8, the protective layer44covers the external connection terminal formation region of the second main face30SB of an image pickup chip30B. That is, the protective layer44has an opening where a portion of the external connection electrode34is exposed. The protective layer44may be formed of a material and by a formation method similar to those of the etching mask39or the like, or of a different material and by a different formation method therefrom.

Since it is not necessary to form the insulating layer43, it is easier to produce the image pickup apparatus10B than the image pickup apparatus10.

Of course, the protective layer44may be also formed on the image pickup apparatus10or the image pickup apparatus10A.

Next, the image pickup apparatus10C of Modification34is described. As shown inFIG. 9A, when the image pickup apparatus10C is produced, a frame-like groove26is formed by, for example, a dicing blade in outer peripheral portions around the respective image pickup chip arrangement regions30S of a glass wafer20WC before the bonding process. The groove26may be formed by etching.

As shown inFIGS. 9B and 9C, an image pickup chip30C is heated and pressurized in an aligned state, and bonded to the glass wafer20WC by using, for example, a flip chip bonder. In the image pickup apparatus10C, an excess amount of the adhesive41L flows into the groove26. Therefore, a fillet is not spread horizontally (a main face parallel direction) or vertically (a main face perpendicular direction). Since the fillet is not spread horizontally, more image pickup apparatuses10C can be fabricated from a single joined wafer40WC by reducing the arrangement length L between the image pickup chips30.

Also, as shown inFIGS. 9D to 9F, since the fillet of the adhesive41L is not spread vertically, the sealing member42is surely filled up to the outer peripheral portions of the image pickup chip30in the sealing member filling process in the image pickup apparatus10C. A resin having a higher sealing effect than that of the adhesive layer41can be used for the sealing member42.

Therefore, the image pickup apparatus10C shown inFIG. 10has higher reliability than the image pickup apparatus10or the like where the adhesive layer41is exposed on an outer face.

Moreover, a wall face and a bottom face of the groove26formed by the dicing blade have, for example, a large arithmetic average roughness: Ra (JIS B 0601:2001) of 0.15 μm or more as surface roughness. Therefore, stray light that is light incident in a direction of the groove26is scattered. That is, there is no possibility that the stray light is reflected and enters the light receiving section31as in a groove whose inner face has small surface roughness.

Next, as shown inFIG. 11, in the image pickup apparatus10D of Modification 4, an image pickup chip30D includes micro lenses38on the light receiving section31, and a cavity (air gap portion)46is provided between the light receiving section31and the cover glass20. The micro lenses38are respectively formed corresponding to pixels of the light receiving section31. Sensitivity of the image pickup apparatus10D is improved by increasing light collection efficiency.

Air or an inert gas is injected to an inner portion of the cavity46. When moisture or the like intrudes into the inner portion from outside, condensation occurs on a back face of the cover glass20or a surface of the image pickup chip30D. Thus, an image may become unclear at a time of image pickup. However, in the image pickup apparatus10D, since the cavity46is sealed by the sealing member42, humidity resistance is improved.

Next, an image pickup unit1of a second embodiment of the present invention is described. Since the image pickup unit1includes, for example, the image pickup apparatuses10,10A to10D, same constituent elements are assigned same reference numerals, and description is omitted.

As shown inFIG. 12, in an endoscope2, the image pickup unit1including the image pickup apparatus10, a lens unit50, an interconnection board52, a signal cable53, and a shield case51is disposed at a distal end portion of an insertion section. The lens unit50composed of a frame member50A and an image pickup optical system50B held in the frame member50A forms an object image on the light receiving section of the image pickup apparatus10. The interconnection board52is connected to the external connection terminal of the image pickup apparatus10. The signal cable53is connected to the external connection terminal via the interconnection board52. The image pickup apparatus10and the interconnection board52are accommodated in the shield case51made of a metal material, and a rear portion side of the image pickup apparatus10and the interconnection board52are sealed by a second sealing member55. An electronic component54such as a chip capacitor is mounted on a surface of the interconnection board52.

As shown inFIG. 13, since an outer periphery of the image pickup apparatus10is covered with the sealing member42made of the insulating material in the image pickup unit1, there occurs no problem even when the image pickup apparatus10is in contact with the shield case51made of metal.

The second sealing member55is made of, for example, a resin with high thermal conductivity obtained by mixing a metal oxide into silicone rubber, and fixes the image pickup apparatus10, the interconnection board52, and the signal cable53etc. to an inner portion of the shield case51. The shield case51electrically shields the image pickup apparatus10, and not only mechanically reinforces the image pickup apparatus10, but also significantly reinforces a sealing function of the image pickup apparatus10.

As already described, in the image pickup apparatus fabricated by the conventional W-CSP method, a side face of the image pickup chip composed of a semiconductor is exposed on an outer face. Therefore, when the side face of the image pickup chip comes into contact with the shield case made of metal, a malfunction could be caused. It is thus necessary to electrically insulate the side face of the image pickup chip, so that an outer dimension (plan-view dimension) is increased.

The distal end portion of the endoscope is exposed to high temperature and high humidity in a disinfecting/sterilizing process or the like. Therefore, when a resin having a poor moisture vapor transmission rate is used for a sealing member of the image pickup chip of the image pickup apparatus, it is not easy to secure reliability of the image pickup apparatus. For example, it is assumed that moisture intrudes via the sealing resin. In a case in which a transparent adhesive layer exists between the light receiving section and the transparent support member, the adhesive layer is altered, and becomes locally opaque, which could be reflected in a picked-up image. Also, in a case in which an air gap of air or inert gas exists between the light receiving section and the transparent support member, the moisture intruding into the air gap forms condensation, which could also be reflected in a picked-up image.

On the contrary, in the image pickup apparatus10, the outer face of the image pickup chip30is covered with any of the cover glass20, the sealing member42, and the insulating layer43, and electrically insulated. Also, the insulating layer43has sealing properties for preventing intrusion of moisture or the like into an inner portion as well as insulating properties.

Therefore, since the image pickup apparatus10has high reliability while being ultra-small, the image pickup apparatus10can be preferably used particularly as an image pickup apparatus disposed at the distal end portion of the endoscope2, or disposed in a capsule endoscope.

Moreover, as shown in a sectional view in a direction perpendicular to a longitudinal direction inFIG. 13, in the image pickup unit1, a plan-view dimension of an inner face of the shield case51and a plan-view dimension of the sealing member42of the image pickup apparatus10are equal to each other, and the shield case51covers the entire outer periphery of the image pickup apparatus10closely with no gap therebetween. To accommodate the image pickup apparatus10within the shield case51in a close contact state, for example, the image pickup apparatus10is accommodated in a state in which the shield case51is heated and expanded, or a metal plate is bent along the image pickup apparatus10, and end faces are joined to create the shield case51. Also, a material, such as resin or glass, with a low moisture vapor transmission rate may be interposed between the shield case51and the image pickup apparatus10.

As described above, the image pickup unit1includes the image pickup apparatuses10,10A to10D or the like, and a side face of the sealing member of the image pickup apparatus is covered over the entire periphery with the shield case composed of a metal plate with an extremely low moisture vapor transmission rate in a close contact state with no gap (space), through which moisture possibly intrudes, therebetween.

Since the sealing resin of the image pickup apparatus10is covered with the shield case with no gap therebetween, moisture hardly intrudes via the sealing resin. Even when exposed to high temperature and high humidity, the image pickup unit1(the endoscope2) can keep high reliability.

Next, Modifications 1 to 3 of the second embodiment are described. Since Modifications 1 to 3 are similar to the image pickup unit1(the endoscope2) of the second embodiment, same constituent elements are assigned same reference numerals, and description is omitted.

In an image pickup unit1E (an endoscope2E) of Modification 1 shown inFIG. 14, a shield case51E in which an image pickup apparatus10E is accommodated integrally extends from a frame member50E. The shield case51E also has a function as the frame member50A that holds some lenses of the image pickup optical system50B. Since the frame member50A and the shield case51E are integrated in the image pickup unit1E (the endoscope2E), moisture intrusion from a joint between the frame member50A and the shield case51E does not occur. Thus, the endoscope2E including the image pickup apparatus10E (the image pickup unit1E) has higher reliability.

Also, a sectional shape (plan-view shape) of a face perpendicular to the longitudinal direction of the shield case is not limited to an approximately square shape shown inFIG. 13. For example, corner portions may be largely chamfered as in a shield case51F of an image pickup apparatus10F (an image pickup unit1F, an endoscope2F) of Modification 2 shown inFIG. 15. A circular shape may be also employed as in a shield case51G of an image pickup apparatus10G (an image pickup unit1G, an endoscope2G) of Modification 3 shown inFIG. 15.

In any case, the image pickup chip is insulated by the sealing resin, and the shield case covers the outer periphery of the insulating resin with no gap therebetween. Thus, the image pickup apparatus (the image pickup unit, the endoscope) has high reliability.

The present invention is not limited to the aforementioned embodiments, and various changes, modifications etc. can be made therein without departing from the scope of the present invention.