Method for manufacturing semiconductor device and semiconductor device

A method for manufacturing a semiconductor device includes: a fixing step in which semiconductor chips are mounted on and fixed to predetermined positions on an upper surface of a single starting substrate to form individual substrates; a connection step in which electrodes of the semiconductor chips and of the starting substrate are connected by wires; a sealing step in which on the upper surface of the starting substrate, the resin is potted among the semiconductor chips to seal an entire lateral circumference of each of the semiconductor chip; a bonding step in which a single starting protective cover to form individual protective covers is bonded to a surface of the resin so as to extend the semiconductor chips; and a cutting step in which an assembly of the semiconductor devices formed by bonding the starting protective cover to the starting substrate via the resin is cut to the semiconductor devices.

TECHNICAL FIELD

The present invention relates to a method for manufacturing a semiconductor device and a semiconductor device.

BACKGROUND ART

Conventional methods for manufacturing an electronic package component by sealing a semiconductor element in a material, for instance, ceramic to form a hollow construction include a method that involves preparing a substrate having a plurality of concave portions, placing a semiconductor element in each of the concave portions, sealing the respective concave portions with a plate-like sealing member over the entire substrate, and cutting the resultant structure at portions in between any two adjacent concave portions to manufacture individual semiconductor devices (see, for instance, PTL 1).

Also, a method for manufacturing a semiconductor device by mounting semiconductor elements on a flat plate-like substrate and sealing them with a lid member having formed concave portions to produce semiconductor devices with respective hollow constructions (see, for instance, PTL 2).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

Forming concave portions at a substrate or a lid member for semiconductor devices as in the conventional technology is more expensive than using a flat plate-like substrate. In addition, a mound which the lid member for sealing sticks to is necessary, making the final semiconductor device larger.

Solution to Problem

According to the 1st aspect of the present invention, a method for manufacturing a semiconductor device including a substrate; a semiconductor chip mounted on the substrate having a functional element; a resin that seals a circumference of the semiconductor chip; and a flat plate-like protective cover bonded to an upper surface of the resin, comprises: a fixing step in which a plurality of semiconductor chips each corresponding to the semiconductor chip in the semiconductor device are mounted on and fixed to predetermined positions on an upper surface of a single starting substrate that is to form individual pieces each corresponding to the substrate in the semiconductor device; a connection step in which electrodes of the plurality of semiconductor chips and corresponding electrodes of the starting substrate are connected by wires, respectively; a sealing step in which on the upper surface of the starting substrate, the resin is provided by potting among the plurality of semiconductor chips to seal the semiconductor chips with the resin over an entire lateral circumference of each of the semiconductor chip; a bonding step in which a single starting protective cover that is to form individual pieces each corresponding to the protective cover is bonded to a surface of the resin so as to extend over the plurality of semiconductor chips; and a cutting step in which an assembly of the semiconductor devices formed by bonding the starting protective cover to the starting substrate via the resin is cut to pieces each corresponding to the semiconductor device, wherein in the bonding step, the starting protective cover is bonded to the upper surface of the resin that seals the entire lateral circumference of each semiconductor chip so that a space in which each of the wires is partially exposed is formed between an upper surface of each semiconductor chip and an inner surface of the starting protective cover.

According to the 2nd aspect of the present invention, it is preferred that in the method for manufacturing a semiconductor device according to the 1st aspect, the resin is provided by potting around each semiconductor chip to a height higher than a height of a highest position of the wires in the sealing step; the bonding step includes a pressing step in which the starting protective cover is pressed against the upper surface of the resin that is in an uncured state or in a semi-cured state; and a sum of a thickness of the starting protective cover and a thickness of the resin that is cured is made larger than a distance from the upper surface of the starting substrate to the highest position of the wire.

According to the 3rd aspect of the present invention, it is preferred that in the method for manufacturing a semiconductor device according to the 1st aspect, the resin is provided by potting to a height larger than the height of the highest position of the wires around each semiconductor chip in the sealing step; and the method comprises a curing step to cure the resin, and a coating step in which an adhesive is coated on the surface of the cured resin; wherein in the bonding process, the starting protective cover is bonded to the surface of the resin with an adhesive.

According to the 4th aspect of the present invention, it is preferred that in the method for manufacturing a semiconductor device according to the 1st aspect, the resin is provided by potting to a height larger than the height of the highest position of the wires around each semiconductor chip in the sealing step; and the bonding step in the method comprises: a coating step in which a resin layer that is to form individual pieces each corresponding to the protective cover is coated on a support sheet; a pressing step in which the support sheet is pressed against an upper surface of the resin in a semi-cured state or in an uncured state via the resin layer; and a peeling/forming step in which after the resin layer and the resin are cured, the support sheet is peeled off and a resin layer that is to form individual pieces each corresponding to the protective cover is bonded to an upper surface of the resin from which the support sheet is peeled off, wherein a sum of a thickness of the resin layer and a thickness of the resin after the peeling/forming step is made larger than a distance from an upper surface of the starting substrate to a highest position of the wire.

According to the 5th aspect of the present invention, it is preferred that in the method for manufacturing a semiconductor device according to the 1st aspect, the resin is provided by potting around each semiconductor chip to a height of the substantially upper surface of the semiconductor chip in the sealing step; the starting protective cover has an opening large enough to surround the wires connected to the electrodes of the starting substrate, and a sum of a thickness of the starting protective cover and a thickness of the resin is made larger than a distance from the upper surface of the starting substrate to a highest position of the wires; and the starting protective cover is pressed against the resin while the resin is in an uncured state or in a semi-cured state to bond the starting protective cover to the resin.

According to the 6th aspect of the present invention, it is preferred that in the method for manufacturing a semiconductor device according to the 1st aspect, the resin is provided by potting around each semiconductor chip to a height of the substantially upper surface of the semiconductor chip in the sealing step; the starting protective cover has an opening large enough to surround the wires connected to the electrodes of the starting substrate, and a sum of a thickness of the starting protective cover and a thickness of the resin is made larger than a distance from the upper surface of the starting substrate to a highest position of the wires; and the starting protective cover is bonded to the cured resin with an adhesive.

According to the 7th aspect of the present invention, a semiconductor device comprises: a substrate; a semiconductor chip that has a functional element and is mounted on the substrate, with electrodes of the functional element and corresponding electrodes of the substrate being connected to each other by wires, respectively; a resin that is provided around the semiconductor chip to a position higher than height of a highest position of the wires to seal semiconductor chip; and a flat plate-like protective cover bonded to a surface of the resin, wherein the protective cover is bonded to an upper surface of the resin that seals an entire circumference of the semiconductor chip so as to form a space in which the wires are partially exposed between the upper surface of the semiconductor chip and an inner surface of the protective cover.

Advantageous Effects of Invention

According to the present invention, semiconductor devices with respective hollow constructions can be manufactured without using any substrate or lid member that is provided with concave portions in the semiconductor devices. In addition, no mound for sticking the lid member is necessary, which makes the semiconductor device smaller.

DESCRIPTION OF EMBODIMENTS

With reference toFIGS. 1 to 16, embodiments of the semiconductor device and of the method for manufacturing the semiconductor device according to the present invention are explained.

FIG. 1is an exploded perspective view showing a semiconductor device according to Embodiment 1 andFIG. 2is a cross-sectional view along the line II-II inFIG. 1.

A semiconductor device10according to Embodiment 1 includes a semiconductor chip1installed on an upper surface of a substrate2, a resin4that seals the circumference of the semiconductor chip1on the substrate2, and a protective cover5that covers the sealing resin4. The sealing resin4has an opening4A. As can be seen formFIGS. 2 and 3, a marginal part of the opening4A actually forms a smooth slope.

The semiconductor chip1is used in devices that need to be sealed, for instance, acceleration sensors and gyro sensors. The cover5is a sheet-like flat plate made of a resin. To the upper surface of the resin4that seals the entire lateral circumference of the semiconductor chip1is bonded a protective cover5so that a space SP, in which a wire3is partially exposed, can be formed between the upper surface of the semiconductor chip1and the inner surface of the protective cover5.

FIGS. 3(a) to (d)are diagrams illustrating the method for manufacturing the semiconductor device10according to Embodiment 1 shown inFIG. 1.

A plurality of semiconductor chips1, a large starting substrate2A, and a protective cover (starting protective cover)5A made of an opaque resin are provided. The starting substrate2A is an insulation substrate, on upper surface of which an electrode pattern or a wiring pattern is formed. The starting substrate2A is fabricated by using, for instance, a glass-epoxy resin, ceramic, or a lead frame. As will be described later, the starting substrate2A is cut to produce each substrate2.

A plurality of semiconductor chips1are arranged and fixed, i.e., installed at predetermined positions on an upper surface of the starting substrate2A. Electrode pads on an upper surface of each semiconductor chip1are connected to corresponding electrode pads on the starting substrate2A via respective bonding wires3(FIG. 3(a)). An interim product inFIG. 3 (a)is indicated with a reference sign10A.

Between any two adjacent members of the semiconductor chips1in the interim product10A shown inFIG. 3 (a)a thermosetting resin4that is flowable is provided by potting. The thermosetting resin4is potted to a height larger than the height of each semiconductor chip1and larger than the height of each bonding wire3. The potted resin4, due to its surface tension and viscosity, rises obliquely at the uppermost edge of the side of the semiconductor chip1to form a nearly trapezoid form in cross-section (seeFIG. 3 (b)). The thermosetting resin4is a light-shielding opaque resin, such as epoxy resin.

The potted thermosetting resin4is heated at a temperature equal to or higher than the curing-start temperature for a predetermined time to bring it into a semi-cured state. If the curing temperature of the resin4is 150° C., the resin4is heated at a heating temperature of about 100° C. to render it semi-cured. This interim product is indicated with a reference sign10B inFIGS. 3(b) and (c). The term “semi-cured state” means a cured state of the resin4such that when the protective cover5A is pressed against the resin4in the bonding step described later, the semi-cured resin4is tacky and deformable but is non-flowable.

The resin4in the interim product10B shown inFIGS. 3(b) and (c)is in a semi-cured state and the surface of the resin4is tacky. A sheet of protective cover5A made of a resin is pressed onto the upper surface of the resin4(FIG. 3 (c)). The pressing force exerted on the cover5A is set so that the semiconductor device1has a predetermined size in height. The pressing force depends on the viscosity of the resin in a semi-cured state. Thus, the heating temperature and heating time for rendering the resin semi-cured, that is, the heating temperature and heating time for obtaining predetermined viscosity of the resin may be determined as appropriate depending on the resin to be used.

The resin4is cured either with or without predetermined pressing force being exerted on the protective cover5A. Reheating is performed at a temperature, for instance, not lower than 150° C. for a predetermined time. After the resin4is completely cured with the protective cover5A being bonded to the resin4, the single starting substrate2A on which the plurality of semiconductor devices10arranged in the form of a matrix is cut into individual pieces to separate the semiconductor devices10(FIG. 3 (d)) to obtain the semiconductor device10shown inFIG. 1.

InFIGS. 3(a) to (d), three semiconductor chips1are shown to be installed on the starting substrate2A. Actually, on the order of several tens to a thousand of semiconductor chips1are mounted in the form of a matrix on the starting substrate2A. Accordingly,FIGS. 3(a) to (d)illustrate each by an example respective portions of the starting substrate2A, the semiconductor chips1mounted on the starting substrate2A, and the sheet-resin-made protective cover5A. The same applies to the figures relating to respective embodiments described hereinbelow.

The semiconductor device10according to Embodiment 1 includes the substrate2, the semiconductor chip1such as an acceleration sensor or a gyro sensor mounted on the substrate2, the resin4that seals the circumference of the semiconductor chip1, and the flat plate-like protective cover5bonded to the surface of the resin4. The semiconductor device10is manufactured by the following manufacturing method. That is, the method includes a fixing step in which a plurality of semiconductor chips1are mounted on and fixed to predetermined positions on the upper surface of the starting substrate2A. The method also includes a connection step in which electrodes of the semiconductor chips1and corresponding electrodes of the starting substrate2A are connected to each other by the wires3, respectively. The method further includes a sealing process in which the entire lateral circumference of each semiconductor chip1is sealed with a resin by means of resin potting among the semiconductor chips1on the upper surface of the starting substrate2A. The method includes a bonding step in which a sheet of the protective cover5A is bonded to the upper surface of the resin4so that the protective cover5A extends over the plurality of the semiconductor chips1. The method further includes a cutting step in which the assembly of the semiconductor devices, which is obtained by bonding the protective cover5A to the starting substrate2A with the resin4therebetween, is cut to separate semiconductor devices10. The protective cover5is bonded to the upper surface of the resin4that seals the entire lateral circumference of the semiconductor chip1so that a space SP, in which a portion of the wire3is exposed, is formed between the upper surface of the semiconductor chip1and the inner surface of the protective cover5A.

The bonding step includes a pressing step. In the pressing step, the protective cover5A is pressed against the upper surface of the resin4in a semi-cured state. In this case, the sum of the thickness of the protective cover5A and the thickness of the resin4after curing is set greater than the distance from the upper surface of the starting substrate2A to the highest position of the wire3.

According to the method for manufacturing a semiconductor device and the semiconductor device according to Embodiment 1 have the following operations and advantageous effects as described below.

(1) Semiconductor devices having a hollow construction can be fabricated without preparing any substrate or lid member that is provided with concave portions. This enables a reduction in cost.

(2) Because it is unnecessary to form any mound portion in the substrate or the lid member, which is provided with the concave portions, the semiconductor device can be made much smaller than ever.

The semiconductor device according to the above-described Embodiment 1 may be modified as follows.

(1) The semiconductor device10may fabricated by using an optical element for the semiconductor chip and using a transparent resin or glass instead of the protective cover5to form an optical semiconductor device.

(2) In Embodiment 1 above, the protective cover5A is pressed against the resin4in a semi-cured state. However, if the resin4has moderate viscosity from the start, the cover5A may be bonded to the resin4before the resin4is semi-cured, that is, subsequent to potting of the resin4. The resin4in a semi-cured state has consistency and adhesion that vary depending on the heating temperature and heating time from the uncured state of the resin and further the resin to be used. The pressing force exerted to the cover5A upon bonding is set as appropriate depending on the consistency of the resin4and so as to disallow the pressed cover5A to contact the bonding wire3to deform or damage it, or to disallow the pressed uncured resin4to migrate onto the semiconductor chip1.

(3) If the curing of the resin4proceeds to cause a reduction in the adhesion of the surface of the resin4, further heating upon pressing the protective cover5A enables the surface of the resin4to soften so as to provide some adhesion unless the resin4is cured completely. The adhesion of the surface of the resin depends on the characteristics of and the cured state of the resin to be used. Accordingly, the pressing force and temperature at the time of attachment of the protective cover5A are set in accordance with the resin and its cured state.

As explained above, the cover5A is bonded making use of the adhesion of the resin4in a semi-cured state. In addition, semi-curing of the resin4has the following effects.

Semi-curing of the resin4enables the resin4to have a shape stabilized to some extent, so that it can be treated with ease.

The resin4may sometimes discharge gas containing an organic component or components. Heating the resin4to some extent for semi-curing it promotes the discharge of the gas. Bonding the cover5A after the gas is sufficiently discharged by the heating eliminates breakage of the cover caused by an increase in pressure as a result of accumulation of the gas discharged from the resin4in the sealed hollow portion (space SP).

The discharged gas contains an organic component or components. If the organic component or components attach to a sensor mounted on the semiconductor chip1, the characteristics of the sensor may be influenced depending on the type of sensor. However, bonding the cover5A to the resin4in a semi-cured state after the gas is sufficiently discharged eliminates influences of the discharged gas to the sensor.

In case the resin discharges a relatively small amount of gas depending on the type of the resin or in case the protective cover5is provided with an opening as in Embodiments 4 to 11 described later, the discharge gas from the resin causes no problem.

FIG. 4is a cross-sectional view of the semiconductor device100according to Embodiment 2.FIG. 4is a diagram corresponding to the cross-section along the line II-II inFIG. 1. In Embodiment 1, the protective cover5A is bonded to the surface of the resin4by pressing the protective cover5A against the surface of the resin4in a semi-cured state and then curing the resin4. In contrast, in Embodiment 2, the protective cover5A is bonded to the surface of the resin4that is in a completely cured state with the adhesive6. The adhesive6may be an epoxy-based adhesive. However, it is not limited to a particular one as far as it can bond the resin4and the protective cover5A made of a thin-film resin to each other.

FIGS. 5(a) and (b)show the method for manufacturing a semiconductor device according to Embodiment 2 of the present invention.

FIG. 5 (a)shows an interim product10D obtained by curing the resin4in a semi-cured state of the interim product10B shown inFIG. 3 (c). The adhesive6is coated to the surface of the resin4of the interim product10D and then the protective cover5A is bonded to the surface of the resin4(FIG. 5 (a)). After the adhesive6is completely cured and the protective cover5A is bonded to the resin4, a plurality of semiconductor devices10arranged in the form of a matrix on the starting substrate2A are cut into separate semiconductor devices10(FIG. 5 (b)) to obtain the semiconductor device10shown inFIG. 4.

In the method for manufacturing a semiconductor device according to Embodiment 2, the sealing step includes potting the resin4to a height that is larger than the height of the highest position of the wires3around the semiconductor chip1. The manufacturing method includes a curing step in which the resin4is cured and a coating step in which the adhesive6is coated on the surface of the cured resin4. In the bonding step, the protective cover5is bonded to the surface of the cured resin4with the adhesive6.

Embodiment 2 also exhibits the same operations and advantageous effects as those obtained in Embodiment 1.

FIGS. 6(a) to (c)illustrate the method for manufacturing a semiconductor device according to Embodiment 3 of the present invention. The semiconductor device10fabricated according to Embodiment 3 is the one shown inFIGS. 1 and 2.

FIG. 6(a)shows the interim product10B shown inFIG. 3 (c), which includes the resin4in a semi-cured state. The thermosetting resin is applied to a flexible support sheet8made of, for instance, metal to form a resin layer7A. While the resin layer7A is in a semi-cured state, the support sheet8with the resin layer7A being down side is attached to the resin4of the interim product10B from above through the resin layer7A as shown inFIGS. 6 (a) and (b).

After the resin layer7A is bonded and completely cured, the support sheet8is peeled off (FIG. 6 (c)). As a result, the interim product10C, which is similar to that shown inFIG. 3 (d), is obtained. The obtained interim product10C is cut to fabricate separate semiconductor devices10.

The support sheet8used has a surface irregularity on the order of 10 μm or less. The reason for this is as follows. That is, the flatter the surface of the support sheet8is, the more easily is released the resin layer7A.

In the method for manufacturing a semiconductor device according to Embodiment 3, the sealing step is achieved by potting the resin4to a height that is larger than the height of the highest position of the wires3around the semiconductor chip1. This method further includes a coating step in which the resin layer7A, which forms the protective cover5, is coated to the support sheet8; a pressing step in which the support sheet8is pressed onto the upper surface of the resin4in a semi-cured state via the resin layer7A; and a peeling/forming step in which after the resin layer7A and the resin4are cured, the support sheet8is peeled off to form a protective cover on the upper surface of the resin layer7A. The sum of the thickness of the protective cover and the thickness of the resin4after the peeling/forming step is set to be larger than the distance from the upper surface of the starting substrate2A to the highest position of the wire3. Thereafter, the assembly of the semiconductor devices is cut to separate semiconductor devices.

Embodiment 3 can exhibit the same operations and advantageous effects as those exhibited in Embodiment 1. By the method according to Embodiment 3, both the resin4and the resin layer7A are bonded to each other while they are in a semi-cured state. This enables the interface between the resin4and the resin layer7A to become a relatively uniform layer. The advantage of the interface between the resin4and the resin layer7A being a relatively uniform layer is that use of the same material provides strong bonding and higher moisture resistance than the bonding achieved by use of different materials.

Variation Example 1 of Embodiment 3

In Embodiment 3, the resin layer7A that is in a semi-cured state is pressed against the surface of the resin4being in a semi-cured state. However, the resin layer7A in a semi-cured state may be attached to the resin4in a cured state.

Variation Example 2 of Embodiment 3

In Embodiment 3, the resin layer7A in a semi-cured state is pressed against the resin4of the interim product10B. However, due to, for instance, the viscosity of the resin layer7A, sufficiently decreased pressing force enables the resin layer7A to be bonded as it is in an uncured state. Further, as explained about Embodiment 1, it is possible to achieve bonding even if the resin4is in an uncured state.

If the resin layer7A is uncured, any contact with the bonding wire3causes no deformation of the bonding wire3because the resin layer7A is deformed.

FIG. 7is an outline view of the semiconductor device20according to Embodiment 4 andFIG. 8is a cross-sectional view along the line VIII-VIII inFIG. 7. The semiconductor device20includes the semiconductor chip1installed on the upper surface of the substrate2, the resin4that seals the semiconductor chip1, and a cover50that covers the surface of the resin4that seals. The semiconductor chip1is a chip of an optical element such as a photodiode (PD) or a light-emitting diode (LED). The resin4has an opening4A. The cover50is a sheet-like flat plate that has an opening51larger than the planar-view shape of the semiconductor chip1.

FIGS. 9 (a) to (c)illustrate the method for manufacturing a semiconductor device according to Embodiment 4 of the present invention.

In Embodiment 1 to 3 above, the protective cover5that is made of a sheet resin and covers the entire upper surface of the semiconductor chip1is used. In Embodiment 4, the semiconductor device20includes the protective cover50provided with an opening51and a frame52instead of the protective cover5. In Embodiment 4, the semiconductor device20is configured to eliminate covering the opening of the semiconductor chip1by the protective cover50.

In Embodiment 4, a resin9is provided by potting between any adjacent two semiconductor chips1to have a height about the same as the height of the semiconductor chips1. The resin9used is a thermosetting resin, for instance, epoxy resin similarly to Embodiment 1. The potted resin9is heated at a temperature equal to or higher than the curing-start temperature for a predetermined time, which renders the resin semi-cured to obtain an interim product20A shown inFIG. 9(a).

Next, a protective cover50A made of a sheet resin having an opening51larger than the semiconductor chip1is pressed against the resin9from above (FIG. 9 (b)). Thereafter, the resin9is completely cured by heating (FIG. 9 (c)). In this case the heating conditions are the same as those in Embodiments 1 to 3. The thickness of the protective cover50A is set so that the upper surface of a frame52is higher than the height of the highest position of the bonding wire3. The opening51is set to be large enough to eliminate contact by the bonding wires3.

FIG. 9(c)shows an interim product20B obtained by completely curing the resin9in a state in which the protective cover50A made of a sheet resin is bonded to it. The interim product20B is cut into individual pieces along cutting lines to obtain the semiconductor device20as shown inFIG. 7andFIG. 8. The semiconductor device20having such a structure can be mounted on, for instance, a larger printed circuit board (PCB) without contacting the bonding wires3.

The PCB on which the semiconductor devices20of this type are mounted is commonly sealed in whole with another cover to protect the semiconductor chips of the semiconductor devices.

In Embodiment 4, the resin9is provided by potting to the height about the same as the height of the semiconductor chip1. However, as can be seen fromFIG. 9(c), if the sum of the height of the resin9and the thickness of the sheet-resin-made cover50A, that is, the thickness of the frame52is larger than the distance from the upper surface of the substrate to the highest position of the bonding wire3, each semiconductor device can be mounted without contacting the bonding wires3. Accordingly, the height of the resin9may be different from the height of the semiconductor chip1.

In the method for manufacturing a semiconductor device according to Embodiment 4, the sealing step is achieved by potting the resin9to the height nearly (substantially) the same as the height of the upper surface of the semiconductor chip1around the semiconductor chip1. The single protective cover50A has an opening51large enough to surround a plurality of wires connected to a plurality of corresponding electrodes of the starting substrate2A. The sum of the thickness of the protective cover50and the thickness of the resin9is set to be larger than the distance from the upper surface of the starting substrate2A to the highest position of the wires3. While the resin9is in a semi-cured state, the protective cover50A is pressed against the resin9to bond it. Thereafter, the resultant structure is individualized to obtain each semiconductor device.

Embodiment 4 also exhibits operations and advantageous effects similar to those in Embodiment 1.

Like the semiconductor device200shown inFIG. 10, the single large protective cover50A (seeFIG. 9 (b)) for fabricating the sheet-resin-made cover50described in Embodiment 5 may be bonded to the resin9by coating the adhesive6on the resin9in the same manner as that in Embodiment 2 (seeFIG. 4). Since the sheet-resin-made cover50is cured, the bonding may be achieved by coating the adhesive on the side of the sheet-resin-made cover50instead of the resin9and pressing the coated side of the sheet-resin-made cover50against the resin9.

In the method for manufacturing a semiconductor device according to Embodiment 5, the sealing step is achieved by potting the resin9to a height position nearly the same as the height of the upper surface of the semiconductor chip1around the semiconductor chip1. The protective cover50A has an opening51large enough to surround the wires3connected to the corresponding electrodes of the starting substrate2A. The sum of the thickness of the protective cover50A and the thickness of the resin9is set to be larger than the distance from the upper surface of the starting substrate2A to the highest position of the wires3. After the resin9is cured, the protective cover50A is bonded to the resin9with the adhesive6.

Embodiment 5 also exhibits similar operations and advantageous effects to those in Embodiment 1.

FIG. 11is a cross-sectional view of the semiconductor device110according to Embodiment 6.FIG. 11is a diagram corresponding to a cross-sectional view along the lines II-II inFIG. 1. In Embodiment 6, a space SP1is formed by arranging a protective cover500above the semiconductor chip1. In Embodiment 6, the cover500of the semiconductor device110is provided with an opening501. The opening501is a small opening having a size of, for instance, 1 mm or less.

The semiconductor device110having such a structure is suitable for use in such a manner as that in which the semiconductor chip1is exposed to external air. This is the case, for instance, if the semiconductor chip1is equipped with a functional element for detecting, for instance, gas or sound.

The size of the opening501in the protective cover500may be varied as appropriate depending on the specification of the semiconductor device.

Embodiment 6 also exhibits similar operations and advantageous effects to those in Embodiment 1.

FIG. 12is a diagram illustrating method for manufacturing a semiconductor device according to Embodiment 6.

As shown inFIG. 12, a sheet-resin-made protective cover500A provided with the opening501smaller than the opening51in the protective cover50A shown inFIG. 9(b)is pressed against the surface of the resin4in a semi-cured state in the interim product10B shown inFIG. 3(c)to bond it.

Embodiment 6 also exhibits similar operations and advantageous effects to those in Embodiment 1.

FIG. 13is a cross-sectional view showing a semiconductor device120according to Embodiment 7, corresponding to a cross-section along the line VIII-VIII inFIG. 7. The protective cover500with the opening501is bonded onto the upper surface of the cured resin4with the adhesive6.

FIG. 14is a diagram illustrating the method for manufacturing a semiconductor device according to Embodiment 8. According to this embodiment, the protective cover500A, which is provided with the opening501that is smaller than the opening51in the protective cover50inFIG. 9 (b), is bonded to the interim product20B (seeFIG. 9 (c)) according to Embodiment 4. The protective cover500A may be bonded to the frame52with an adhesive.

Alternatively, though not shown, the frame52may further be potted with a resin and while the potted resin is in a semi-cured or uncured state, the protective cover500A may be pressed against the frame52to bond it.

FIG. 15(a)is a cross-sectional view showing a semiconductor device300according to Embodiment 9, corresponding to the cross-section along the line VIII-VIII inFIG. 7.

FIG. 15(b)is a cross-sectional view showing a semiconductor device310according to Embodiment 10, corresponding to a cross-section along the line VIII-VIII inFIG. 7.

The semiconductor devices300and310use a cover550that covers upside of the bonding wires3and is provided with an opening551being large enough to uncover upside of the element mounted in the semiconductor chip1.

The semiconductor device300according to Embodiment 9 shown inFIG. 15 (a)is fabricated by pressing the protective cover550made of a resin sheet to the surface of the resin4in a semi-cured state to bond it.

The semiconductor device310according to Embodiment 10 shown inFIG. 15(b)is fabricated by bonding the protective cover550made of a resin sheet to the upper surface of the cured resin4with the adhesive6.

FIG. 16is a cross-sectional view showing a semiconductor device320according to Embodiment 11, corresponding to the cross-section along the line VIII-VIII inFIG. 7. The semiconductor device320includes, mounted on the upper surface of the substrate2, two semiconductor chips1aand1bhaving different functions from each other. A protective cover560for these semiconductor chips are each provided with an opening561athat opens upside of the functional element or semiconductor chip1aand an opening561bathat opens upside of the functional element or semiconductor chip1b, respectively.

The above explanations relate to exemplary embodiments of the present invention and the present invention is not limited to these embodiments and variation examples. It is possible for a person skilled in the art to combine the embodiments and variation examples in any desired manner without damaging the features of the present invention and practice the present invention in various modified manner.

For instance, the sealed structure in Embodiment 1 can be adopted in semiconductor chips on which one or more optical elements such as a photodiode (PD) and a light-emitting diode (LED) are mounted or in semiconductor chips including an erasable programmable read only memory (EPROM). In this case, naturally a plate made of a transparent resin or a glass plate is used as the cover5A.

In Embodiments 1 to 11 described above, explanation is made taking a thermosetting resin as an example of the resin4used. However, the present invention is not limited to it and materials other than the thermosetting resin may be used as the resin4. For instance, an ultraviolet curable resin may be used as the resin4.

In Embodiments 1 to 11, explanation is made on the example in which after the bonding step to bond the protective cover5A,50A, or500A to the upper surface of the resin4so as to extend over a plurality of semiconductor chips1, the cutting step is performed to cut the starting substrate2A, to which the single protective cover5A,50A, or500A is bonded through the resin4, into separate semiconductor devices. However, the method for manufacturing a semiconductor device according to the present invention is not limited to this. For instance, the starting substrate2obtained by installing a plurality of semiconductor chips1and sealing them with the resin may be individualized by cutting the obtained structure in correspondence to individual semiconductor devices and then bonding the sheet-resin-made protective cover5,50,500,550, or560to the resin4of each of the resultant individual semiconductor devices. Specifically, after the resin4is provided on the starting substrate2by potting, the resultant starting substrate2is cut into pieces in correspondence to the individual semiconductor devices. Thereafter, the protective cover5is bonded onto the surface of the resin4with the adhesive6.

The disclosure of the following priority application is incorporated herein by reference:

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