JP7266036B2 - Temporary fixing substrate, temporary fixing method, and method for manufacturing electronic component - Google Patents

Description

The present invention relates to a temporary fixing substrate for a silicon substrate, a temporary fixing method, and a method for manufacturing an electronic component.

In recent years, there has been an increasing demand for miniaturization and low-profile electronic components, and silicon substrates for manufacturing such components are often used in an extremely thin state. At this time, since the thinned silicon substrate lacks rigidity and cannot withstand processes such as transportation, grinding, and polishing, a method of supporting the silicon substrate using a temporary fixing substrate made of glass or ceramics is known ( Patent documents 1, 2, 3).

In these conventional techniques, a silicon substrate is bonded to a temporary fixing substrate with a thermosetting resin, cooled, and then thinned by grinding and polishing. Next, multilayer wiring is formed on the surface, and then the silicon substrate is peeled off from the temporary fixing substrate and diced into desired dimensions. A peeling layer is provided in advance on the adhesive layer, and a laser beam is applied to the peeling layer from the side of the temporary fixing substrate to separate the silicon substrate from the temporary fixing substrate.

When the silicon substrate is adhered to the temporary fixing substrate with a thermosetting resin, the bonded body warps due to the difference in thermal expansion between the silicon substrate and the temporary fixing substrate. Therefore, in Patent Document 2, an attempt is made to reduce the warpage of the adhesive body by previously curving the support substrate in the direction opposite to the warpage of the adhesive body. The warping of the supporting substrate is adjusted by heat deformation, changing the polishing method, and removing the work-affected layer.

JP 2011-023438 JP 2010-058989

However, due to constraints such as the type of thermosetting resin, the bonding temperature, and the thickness of the temporary fixing substrate and the silicon substrate, the amount of bending of the bonded body after bonding may increase. In this case, it is necessary to increase the initial amount of bending of the temporary fixing substrate toward the opposite side in accordance with the amount of bending of the adhesive body. However, in such a case, handling of the substrates by the bonding equipment becomes difficult during bonding, and the substrates may crack due to the pressure during bonding. Further, when the silicon substrate is thinned by grinding and polishing after obtaining the bonded body, the amount of curvature of the bonded body approaches the initial amount of curvature of the temporary fixing substrate before bonding to the silicon substrate. For this reason, the amount of bending becomes greater than the amount of bending of the bonded body immediately after bonding, making it difficult to carry out subsequent processes.

An object of the present invention is to provide a temporary fixing substrate having a fixing surface for bonding and temporarily fixing a silicon substrate or an electronic component chip and a bottom surface on the opposite side of the fixing surface, wherein the temporary fixing substrate is a silicon substrate or an electronic component chip. To further reduce the amount of bending of an adhesive body after bonding to a chip.

The present invention is a temporary fixing substrate made of ceramics or glass, comprising a fixing surface for bonding and temporarily fixing at least one of a silicon substrate and an electronic component chip, and a bottom surface opposite to the fixing surface. hand,
It has an outer peripheral flat plate portion and a recessed deformed portion surrounded by the outer peripheral flat plate portion, and the fixing surface is a flat surface on the outer peripheral flat plate portion.

Further, the present invention further comprises a step of bonding at least one of the silicon substrate and the electronic component chip to the fixing surface of the temporary fixing substrate to obtain an adhesive body, and a step of separating the silicon layer from the temporary fixing substrate. characterized by having

The present invention also provides a step of bonding the silicon substrate to the fixing surface of the temporary fixing substrate to obtain an adhesive body;
a step of processing the silicon substrate of the adhesive body to thin the silicon substrate and form a silicon layer;
A method for manufacturing an electronic component, comprising the steps of: providing an electronic component chip in or on the silicon layer; and separating the silicon layer and the electronic component chip from the temporary fixing substrate. is.

Further, the present invention is characterized by comprising a step of bonding the electronic component chip to the fixing surface of the temporary fixing substrate to obtain an adhesive body, and a step of separating the electronic component chip from the temporary fixing substrate. , and a method for manufacturing an electronic component.

According to the present invention, the temporary fixing substrate comprising a fixing surface for bonding and temporarily fixing at least one of a silicon substrate and an electronic component chip, and a bottom surface on the opposite side of the fixing surface, is made of ceramics. Even if the initial curvature of the fixing substrate is the same, the amount of bending of the adhesive body after bonding the temporary fixing substrate to the silicon substrate or the electronic component chip can be further reduced. As a result, there is no need to excessively increase the amount of initial curvature of the temporarily fixed substrate, each substrate can be easily handled in the bonding equipment, and cracking due to pressure during bonding can be suppressed. Further, after obtaining the bonded body, for example, after thinning the silicon substrate by grinding and polishing, the amount of bending of the bonded body can be reduced, and the subsequent handling of the bonded body is facilitated.

(a) shows the silicon substrate 2 and the temporary fixing substrate 1 before bonding, (b) shows the bonding body obtained by bonding the silicon substrate 2 and the temporary fixing substrate 1, and (c) shows the silicon substrate of the bonding body. The thinned state of layer 2A is shown. (a) shows a state in which the wiring 6 is provided on the silicon layer 2A, and (b) shows a state in which the temporary fixing substrate 1 is separated from the silicon substrate. (a) is a schematic diagram showing a silicon substrate 12 and a curved temporary fixing substrate 11 (before bonding), and (b) shows a state in which the silicon substrate 12 and the temporary fixing substrate 11 are bonded. , (c) shows the adhesive body 14 . (a) shows the state in which the silicon layer 14A of the adhesive is thinned, (b) shows the adhesive between the silicon layer 14A and the temporary fixing substrate 11A, and (c) shows the silicon layer 12B as the temporary fixing substrate. 11A separated. (a) shows a material 20 before processing, (b) shows a temporary fixing substrate 21 according to an embodiment of the present invention, and (c) is a plan view of the temporary fixing substrate 21. FIG. (a) is a schematic diagram showing the silicon substrate 22 and the temporary fixing substrate 21 (before bonding), (b) shows the state in which the silicon substrate 22 and the temporary fixing substrate 21 are bonded, and (c) ) indicates the adhesive 23 . (a) shows the state in which the silicon substrate 22B of the bonded body is thinned, (b) shows the bonded body between the silicon substrate 22B and the temporary fixing substrate 21A, and (c) shows the silicon substrate 22B as the temporary fixing substrate. 21 is shown separated. FIG. 8 is a schematic diagram showing a rectangular temporary fixing substrate 31 when viewed in plan. (a) shows a state in which the electronic component chip 36 is temporarily fixed by the resin mold 35, and (b) shows a state in which the electronic component 36 and the resin mold 35 are separated from the temporary fixing substrate 1 by light irradiation.

First, referring to FIGS. 1 and 2, a method for temporarily fixing and separating a silicon substrate using a temporary fixing substrate will be described.
First, in the example shown in FIG. 1A, a predetermined conductor 3 is provided on the bonding surface 2a side of the silicon substrate 2. As shown in FIG. Then, an adhesive layer 4 and a peeling layer 5 are provided on the surface 2a of the silicon substrate 2. As shown in FIG. The bonding surface 1a of the temporary fixing substrate 1 is made to face the surface 5a of the release layer 5. As shown in FIG.

Next, as shown in FIG. 1(b), the silicon substrate 2 and the temporary fixing substrate 1 are bonded to obtain an adhesive body. Next, the non-bonding surface 2b of the silicon substrate 2 is processed to thin the silicon layer 2A as shown in FIG. 1(c). 2c is a processing surface. In this example, the conductor 3A penetrates the silicon layer 2A when the silicon layer 2A is thinned.

Next, as shown in FIG. 2A, a predetermined wiring layer 6 is formed on the silicon substrate 2A. Reference numeral 7 denotes a rewiring layer for supplying power to a device chip (electronic component chip) placed on the wiring layer, and is formed by photoprocessing or plating. If necessary, a plurality of device chips are placed on the wiring layer (not shown), then a laser beam having a predetermined wavelength and energy is irradiated from the temporary fixing substrate side, and the temporary fixing substrate 1 is separated from the peeling layer 5. Cause delamination. As a result, as shown in FIG. 2(b), the silicon layer 2A is separated from the temporary fixing substrate together with the adhesive layer 4 and the wiring layer 6, and is subjected to the next processing step.

Here, when the silicon substrate is adhered to the temporary fixing substrate with a thermosetting resin, the bonding body is curved due to the difference in thermal expansion between the silicon substrate and the temporary fixing substrate. Therefore, as shown in FIG. 3A, a method is known in which the temporary fixing substrate 11 is preliminarily curved in a direction opposite to that of the bonding body. That is, the temporary fixing substrate 11 is curved so that the bonding surface 11a of the temporary fixing substrate 11 is recessed and the joint surface 11b is bulging. 12a is a bonding surface and 12b is a non-bonding surface. Here, L is a virtual surface when the temporary fixing substrate 11 is not curved, and W is the amount of curvature. is a plus sign.

Next, as shown in FIG. 3(b), the temporary fixing substrate 11 and the silicon substrate 12 are sandwiched between jigs 13, and heated while being pressurized as indicated by arrow A. Next, as shown in FIG. Preferably, a thermosetting adhesive (not shown) is interposed between the temporary fixing substrate 11 and the silicon substrate 12, and is effective to bond the temporary fixing substrate 11 and the silicon substrate. At this point, both the temporary fixing substrate 11 and the silicon substrate 12 are flattened by heating and pressing.

When the bonding is completed, as shown in FIG. 3(c), an adhesive body 14 of the temporary fixing substrate 11A and the silicon substrate 12A is obtained. However, in the adhesive body, the temporary fixing substrate 11A warps in the opposite direction from the initial state. This is because the temporary fixing substrate 11A has a larger coefficient of thermal expansion than silicon, so it shrinks in the direction of arrow B when cooled, and as a result, the entire bonding body 14 curves toward the opposite side. The amount of curvature W becomes a plus sign.

Next, as shown in FIG. 4(a), the bonded body 14A is placed on the flat surface 15a of the jig 15, and pressure is applied in the direction of arrow C to flatten the bonded body. As a result, the silicon substrate is thinned to form a thin silicon layer 12B, and the silicon layer and the temporary fixing substrate 11A are flattened. Next, when the bonded body 14A is removed from the jig 15, the bonded body 14A is curved again as shown in FIG. 4(b). However, the amount of curvature W of the adhesive body 14A is smaller than the amount of curvature W before thin plate processing as shown in FIG. a)).

Next, as shown in FIG. 4(c), the silicon layer is separated from the temporary fixing substrate. At this time, the shape of the temporary fixing substrate 11A tends to return to the initial shape. On the other hand, since the silicon layer is thinned, it is almost flat.

Here, by setting the initial amount of curvature W of the temporary fixing substrate 11 in FIG. plus sign opposite to the initial) can be decreased. However, due to constraints such as the type of thermosetting resin, the bonding temperature, and the thickness of the temporary fixing substrate and the silicon substrate, the amount of bending of the bonded body after bonding may increase (FIG. 3(c)). In this case, it is necessary to increase the initial amount of bending of the temporary fixing substrate toward the opposite side according to the amount of bending of the adhesive (FIG. 3A). However, in such a case, handling of the substrates in the bonding equipment becomes difficult during the bonding shown in FIG. Further, when the silicon substrate is thinned by grinding and polishing after obtaining the bonded body, the amount of curvature of the bonded body approaches the initial amount of curvature of the temporary fixing substrate before bonding to the silicon substrate (FIG. 4(b)). For this reason, the amount of bending becomes greater than the amount of bending of the bonded body immediately after bonding, making it difficult to carry out subsequent processes.

5 to 8 relate to an embodiment of the invention.
FIG. 5(a) shows the material 20 of the temporary fixing substrate. The thickness of the temporary fixing substrate material 20 (the distance between the pair of main surfaces 20a and 20b) is constant.

Next, as shown in FIGS. 5(b) and 5(c), the material 20 is deformed so that the principal surface 20a side is recessed to obtain the temporary fixing substrate 21. Next, as shown in FIG. Here, the thickness of the temporary fixing substrate 21 (the distance between the pair of main surfaces 21a and 21b) is constant. A peripheral flat plate portion 21 c is provided on the peripheral edge portion of the temporary fixing substrate 21 , and a concave deformation portion 21 d is provided inside the temporary fixing substrate 21 . The outer peripheral flat plate portion 21c has a ring-shaped flat plate shape and maintains the shape before processing shown in FIG. 5(a). L is a virtual surface along the main surface 21a (flat surface 21e) of the outer peripheral flat plate portion 21c. On the other hand, the concave deformation portion 21d is deformed downward (toward the main surface 21b) from the imaginary plane L and is concave. In this example, the planar shape of the concave deformation portion 21d is circular. Let the amount of curvature W be the maximum value of the recess from the imaginary plane L of the concave deformation portion 21b.

In the example shown in FIG. 6A, the bonding surface 22a of the silicon substrate 22 and the bonding surface 21a of the temporary fixing substrate 21 are opposed to each other. A predetermined adhesive layer or peeling layer can be further formed on the bonding surface 22a side of the silicon substrate 22. FIG. Next, as shown in FIG. 6(b), the temporarily fixed substrate 21 and the silicon substrate 22 are sandwiched between jigs 13, and heated while being pressurized as indicated by arrow A. Next, as shown in FIG. A thermosetting adhesive (not shown) is interposed between the temporary fixing substrate 21 and the silicon substrate 22, and is effective to bond the temporary fixing substrate 21 and the silicon substrate 22 together. At this point, both the temporary fixing substrate 21 and the silicon substrate 22 are flattened by heating and pressing.

When the bonding is completed, as shown in FIG. 6(c), an adhesive body 23 of the temporary fixing substrate 21A and the silicon substrate 22A is obtained. However, in the bonded body, the temporary fixing substrate 21A is along the side opposite to the initial one. This is because the temporary fixing substrate 21A has a larger coefficient of thermal expansion than silicon, so it shrinks in the direction of arrow B when cooled, and as a result, the entire bonding body 23 curves toward the opposite side.

Next, as shown in FIG. 7(a), the bonded body 23 is placed on the flat surface 15a of the jig 15, and pressure is applied in the direction of arrow C to flatten the bonded body. As a result, the silicon substrate 22A is thinned to form a thin silicon layer 22B, and the silicon layer and the temporary fixing substrate are flattened. 22c is a processing surface. Next, when the bonded body 23A is removed from the jig 15, the bonded body 23A is curved again as shown in FIG. 7(b). However, the temporary fixing substrate is close to the initial shape. That is, the amount of curvature W of the adhesive body 23A is smaller than the amount of curvature W before thin plate processing as shown in FIG. 6C, and approaches the shape of the temporary fixing substrate before bonding.

Next, as shown in FIG. 7C, the silicon layer 22B is separated from the temporary fixing substrate. At this time, the shape of the temporary fixing substrate 21 tends to return to the initial shape. On the other hand, since the silicon substrate is thinned, it is almost flat.

Here, in the present invention, as shown in FIG. 6(a), even if the amount of initial curvature of the temporary fixing substrate is the same, when the temporary fixing substrate is bonded to the silicon substrate (FIG. 6(b)) ), the outer peripheral flat plate portion 21 c is not deformed, and only the concave deformation portion 21 d is flattened by the jig 13 . Since the outer peripheral flat plate portion is ring-shaped and surrounds the concave deformation portion, it acts as an anchor to prevent the shape of the temporarily fixed substrate from being greatly deformed. As a result, it is possible to reduce the amount of bending after the bonded body 23 is removed from the jig 13 (see FIG. 6(c)).

As a result, even if the initial amount of bending of the temporarily fixed substrate is the same, the amount of bending after removing the bonding body 23 from the jig 13 can be reduced. In addition, when the amount of bending after removing the adhesive body 23 from the jig 13 is the same, the amount of initial bending of the temporarily fixed substrate can be reduced. Therefore, each substrate can be easily handled in bonding equipment, and cracking due to pressure during bonding can be suppressed. In addition, after obtaining the bonded body and thinning the silicon substrate by grinding and polishing (see FIG. 7(b)), the amount of bending of the bonded body 23A can be reduced, and the subsequent handling of the bonded body is facilitated. .

Embodiments in which the temporary fixing substrate of the present invention is used for bonding electronic component chips will be described below.
First, an electronic component is adhered to the fixing surface of the temporary fixing substrate and temporarily fixed by resin molding. For example, as shown in FIG. 9A, an adhesive layer is provided on the fixing surface 1a of the temporary fixing substrate 1. As shown in FIG. Examples of such adhesives include double-sided tapes and hot-melt adhesives. Various methods such as roll coating, spray coating, screen printing, and spin coating can be employed as methods for providing the adhesive layer on the temporary fixing substrate.

Next, a large number of electronic components 36 are placed on the temporary fixing substrate 1 and the adhesive layer is cured to form the adhesive layer 34 . This curing step is carried out according to the properties of the adhesive, and heating and ultraviolet irradiation can be exemplified.

Next, a liquid resin molding agent is poured and cured. As a result, the electronic component 36 is fixed inside the resin mold 35, as shown in FIG. 9(a). However, 35b is a resin that fills the gap 37 of the electronic component, and 35a is a resin that covers the electronic component.
Examples of molding resins include epoxy resins, polyimide resins, polyurethane resins, and urethane resins.

Next, as indicated by arrow A, the electronic component 36 and the resin mold 35 are separated from the temporary fixing substrate 1 by irradiating light from the bottom surface 1b side of the temporary fixing substrate 1 (see FIG. 9B).
The wavelength of the light irradiated from the bottom side of the temporary fixing substrate can be appropriately changed depending on the type of electronic component or resin mold, and can be, for example, 200 nm to 400 nm.

Each component of the present invention will be further described below.
The material of the temporary fixing substrate is preferably ceramics in terms of mechanical strength and durability against chemicals, and particularly preferably alumina, aluminum nitride, YAG, sialon, and spinel.

In a preferred embodiment, the material constituting the temporary fixing substrate is translucent alumina. In this case, 100 ppm or more and 300 ppm or less of magnesium oxide powder is added to high-purity alumina powder of preferably 99.9% or more (preferably 99.95% or more) purity. As such a high-purity alumina powder, a high-purity alumina powder manufactured by Taimei Chemical Industry Co., Ltd. can be exemplified. The magnesium oxide powder preferably has a purity of 99.9% or more and an average particle size of 50 μm or less.

In a preferred embodiment, 200 to 800 ppm of zirconia (ZrO ₂ ) and 10 to 30 ppm of yttria (Y ₂ O ₃ ) are preferably added to the alumina powder as sintering aids.

A method for molding the temporary fixing substrate is not particularly limited, and may be any method such as a doctor blade method, an extrusion method, or a mold casting method. Particularly preferably, the base substrate is manufactured using a doctor blade method.

In a preferred embodiment, a slurry containing ceramic powder, a dispersion medium and a binder is prepared, the slurry is formed into a tape shape by a doctor blade method, and the tape is laminated to a desired thickness and punched out. A compact is obtained in this way.

The compact is then dried, preferably calcined in air, and then calcined in hydrogen. The sintering temperature during main firing is preferably 1700 to 1900° C., more preferably 1750 to 1850° C., from the viewpoint of densification of the sintered body. The surface of this sintered body is polished with a dial wrap or the like to adjust the thickness unevenness to a certain level or less, and both surfaces are mirror-finished.

After generating a sufficiently dense sintered body at the time of firing in this way, the amount of curvature can be adjusted with high accuracy by adjusting the thickness unevenness, mirror-finishing the surface, and performing annealing treatment. From the viewpoint of preventing deformation and abnormal grain growth, the annealing temperature is preferably 1700° C. or lower, and more preferably the maximum temperature is 1600° C. or lower. On the other hand, the temperature is preferably 1200° C. or higher, more preferably 1400° C. or higher, in order to sufficiently perform creep deformation of the sintered body and adjust the amount of curvature with high precision. Also, the annealing time is preferably 1 to 6 hours.

Further, the glass constituting the temporary fixing substrate may be silicate-based glass or borosilicate-based glass.

The temporary fixing substrate of the present invention has an outer peripheral flat plate portion and a concave deformed portion surrounded by the outer peripheral flat plate portion, and the fixing surface is a flat surface in the outer peripheral flat plate portion. Here, the width F of the outer peripheral flat plate portion (see FIGS. 5B and 5C) is preferably 4% or more of the width R of the temporary fixing substrate 21, thereby suppressing the amount of bending of the adhesive body. more effective. From this point of view, the width F of the outer peripheral plate portion is more preferably 8% or more of the width R of the temporary fixing substrate 21, and particularly preferably 10% or more.

Further, the width F of the outer peripheral flat plate portion is preferably 60% or less of the width R of the temporary fixing substrate 21, thereby enhancing the effect of suppressing the amount of bending of the adhesive body. From this point of view, the width F of the outer peripheral plate portion is more preferably 40% or less of the width R of the temporary fixing substrate 21, and particularly preferably 30% or less.

Note that the width R of the temporary fixing substrate is the length of a line segment crossing the temporary fixing substrate in plan view. The width F of the outer peripheral flat plate portion is the sum of the lengths of the line segments crossing the outer peripheral flat plate portion among the line segments crossing the temporary fixing substrate in plan view. For example, in the plan view shown in FIG. 5(c), the widths of the two outer peripheral flat plate portions in the width direction of the temporary fixing substrate are each F/2. , (F/2+F/2)=F.

Further, the width R of the temporary fixing substrate and the width F of the peripheral flat plate portion may change depending on the direction of the line segment crossing the temporary fixing substrate. For example, in the example shown in FIG. 8, the planar shape of the temporary fixing substrate 31 is rectangular, and the thickness of the temporary fixing substrate 31 (the distance between the main surface 31a and the opposite main surface) is constant. An outer peripheral flat plate portion 31c is provided on the peripheral edge portion of the temporary fixing substrate 31, and a concave deformation portion 31d is provided inside the outer peripheral flat plate portion 31c. The outer peripheral flat plate portion 31c has a flat plate shape, and the main surface 31a of the outer peripheral flat plate portion 31 forms a flat surface 31e. The concave deformation portion 31d is deformed downward from the imaginary plane and is concave. In this example, the planar shape of the concave deformation portion 31d is a rectangle. For example, when the planar shape of the temporary fixing substrate is rectangular, the width R2 in the vertical direction is different from the width R1 in the horizontal direction, and the width F2 (F2/2+F2/2) of the peripheral flat plate portion in the vertical direction is and the lateral width F1 (F1/2+F1/2) of the outer peripheral plate portion may differ. In this case, it is preferable that (the width of the peripheral flat plate portion/the width of the temporary fixing substrate (F1/R1, F2/R2)) be 4 to 60% in the vertical direction and the horizontal direction.

In the temporarily fixed substrate before bonding, the amount of curvature W of the concave deformation portion is preferably 0.1 mm or more, thereby suppressing the amount of curvature of the adhesive body. From this point of view, the curvature amount W of the concave deformation portion is more preferably 0.3 mm or more, and particularly preferably 0.6 mm or more.

As for the shape of the concave deformed portion, the cross-sectional contour can be arc-shaped, parabolic, conical, or dish-shaped. However, in order to effectively suppress the amount of curvature, it is preferable that the cross-sectional contour of the concave deformation portion is parabolic. Further, by making the boundary portion between the outer peripheral flat portion and the curved portion gentle (increasing the radius of curvature R), it is possible to suppress the occurrence of cracks when bonding to the silicon substrate.

In addition, in the temporarily fixed substrate before bonding, it is preferable that the amount of curvature of the concave deformation portion is 2.5 mm or less. easy. From this point of view, the amount of curvature of the concave deformation portion is preferably 2.0 mm or less, more preferably 1.0 mm or less.

At this time, if the thickness unevenness (so-called TTV) in the entire temporary fixing substrate is large, the thickness unevenness of the adhesive layer occurs when the silicon substrate and the electronic component chip are bonded together, causing deformation after bonding. Thickness unevenness is preferably 10 μm or less. Further, when highly accurate wiring is formed on a bonded silicon substrate or electronic component chip, the thickness unevenness is preferably 5 μm or less, more preferably 3 μm or less.

The amount of curvature of the concave deformed portion is measured as follows. That is, the imaginary surface L is obtained by extending the fixing surface (flat surface) of the outer peripheral plate portion onto the concave deformation portion. Then, the depth of the deepest portion of the concave deformed portion as viewed from the imaginary plane L is defined as the amount of curvature W. As shown in FIG. As a specific measuring device, it is possible to measure the shape of a substrate placed on a flat table with a laser length measuring machine.

The planar shapes and planar dimensions of the temporary fixing substrate and the silicon substrate are not particularly limited. The temporary fixing substrate and the silicon substrate or the like may have the same planar shape and planar dimensions, or may have different planar shapes and planar dimensions. Specifically, for example, each of the temporary fixing substrate, the silicon substrate, and the like may be disk-shaped, rectangular, oval, elliptical, triangular, polygonal, or the like. In particular, it is preferable that the temporary fixing substrate and the silicon substrate are point-symmetrical, such as a disk shape or a regular polygonal shape, and more preferably a disk shape. In this case, thermal contraction occurs evenly in each azimuth around the axis of point symmetry.

When the temporary fixing substrate, the silicon substrate, or the like is disc-shaped, the diameter (width) is preferably 100 to 300 mm. When orientation flats and notches are formed on the silicon substrate, forming similar orientation flats and notches on the temporary fixing substrate facilitates positioning during adhesion and reduces adhesion misalignment. Further, when the temporary fixing substrate and the silicon substrate are square or rectangular, the length of one side is preferably 100 to 1000 mm. In this case, it is preferable to form the corners in an R or C shape from the viewpoint of suppressing the amount of bending after bonding.

The thickness of the temporary fixing substrate is, for example, preferably 0.2 to 5.0 mm, more preferably 0.5 to 2.0 mm. By setting this to 0.2 mm or more, it becomes easy to suppress warpage after bonding, and it becomes easy to prevent breakage of the temporarily fixed substrate. Further, by setting this to 5.0 mm or less, the weight of the substrate can be suppressed and the transportation becomes easier.

When the temporary fixing substrate and the silicon substrate or the like are bonded using a thermosetting resin, the temporary fixing substrate and the silicon substrate or the like are superimposed and pressurized and fixed, and heated to cure the thermosetting adhesive. Thus, an adherent is obtained.

Examples of adhesives for bonding the temporary fixing substrate and the silicon substrate include thermosetting resins, UV (ultraviolet curable) adhesives, double-sided tapes, hot-melt adhesives, and the like. Moreover, various methods such as roll coating, spray coating, screen printing, and spin coating can be employed as the method of providing the adhesive on the temporary fixing substrate.

Moreover, it is preferable to form a release layer between the adhesive layer and the temporary fixing substrate. As such a release layer, in addition to the laser release type in which the release layer is carbonized and peeled off by laser light irradiation, the UV release type in which the release layer is deactivated by UV light irradiation, loses its adhesiveness and peels off, and is heated. It is also possible to employ a heat-peeling type in which the components in the layer are foamed and peeled off.

Various electronic component structures can be fabricated on the silicon substrate of the present invention. For example, when manufacturing a CCD or a CMOS, a wiring layer is formed by bonding a silicon substrate to a temporary fixing substrate, thinning the silicon substrate, and then performing a thin film forming process and a patterning process. At this time, if the bonding body between the temporary fixing substrate and the silicon substrate has a large curvature, it is difficult to pattern a fine wiring structure with high precision in the patterning process, so the present invention is particularly useful.

Also, electronic component chips can be placed on a silicon substrate, and each electronic component chip can be electrically connected to the wiring layer. After the silicon substrate is separated from the temporary fixing substrate, the electronic component chips can be separated by cutting the silicon substrate.

Also, the present invention can be suitably applied to so-called FOWLP technology. In FOWLP technology, electronic component chips are once relocated on a support wafer (temporary fixed substrate), sealed with a resin mold, wiring is formed on the surface of the resin mold, and then the electronic component chips and mold resin are supported. A thin structure can be realized by peeling from the wafer (temporary fixing substrate). Then, after the resin mold and the electronic component chips sealed therewith are separated from the temporary fixing substrate, the resin mold can be cut to separate the respective electronic component chips. Even in this case, when the electronic component chip is resin-sealed and the wiring is formed on the temporary fixing substrate, there is a problem of the bending of the adhesive due to the difference in thermal expansion between the members. can improve this.

Further, when the electronic component to be adhered to the temporary fixing substrate has a large area, there is a problem of bending of the adhesive due to the difference in thermal expansion between the temporary fixing substrate and the electronic component chip. can be improved. In particular, when the area occupied by the electronic component chip exceeds 60% of the area of the temporary fixing substrate, this tendency becomes remarkable, so the present invention is useful.

When forming the peripheral flat plate portion and the concave deformation portion on the temporary fixing substrate, a jig having a flat portion that fits the peripheral flat plate portion and a protrusion that fits the concave deformation portion is prepared, and the temporary fixing substrate is heated. It is plastically deformed by pressing the jig while pressing. Alternatively, by placing a flat plate in a mold having similar flat portions and protrusions and pressing the mold while heating, the outer peripheral flat plate portion and the recessed deformation portion can be formed.

A grinder can be used when thinning the silicon substrate by processing. That is, a desired thickness can be obtained by fixing the temporarily fixed substrate side of the bonded body of the temporarily fixed substrate and the silicon substrate with a vacuum chuck or the like and processing the silicon substrate side with a grinding wheel.

(Examples 1 to 7)
A slurry was prepared by mixing the following ingredients.
(Raw material powder)
・ 100 parts by mass of α-alumina powder with a purity of 99.99% ・ MgO (magnesia) 250 ppm
・ZrO2 (zirconia) 400 ppm
・Y2O3 (yttria) 15 ppm
(dispersion medium)
・ 45 parts by mass of 2-ethylhexanol (binder)
・PVB resin 4 parts by mass (dispersant)
・ Polymeric surfactant 3 parts by mass (plasticizer)
・DOP 0.1 part by mass

This slurry was formed into a tape shape using a doctor blade method so that the thickness after firing was 0.7 mm, and the tape was cut to have a size of φ300 mm after firing. After calcining (pre-firing) the obtained powder compact at 1240° C. in the atmosphere, the substrate was placed on a molybdenum plate and held at 1800° C. for 2.5 hours in an atmosphere of hydrogen 3:nitrogen 1. , was fired. Thereafter, grinding with a grinder, lapping with diamond abrasive grains, and polishing with CMP liquid were performed in order to obtain a temporary fixing substrate material 20 having a thickness of 0.6 mm (FIG. 5(a)).

Next, the material 20 was sandwiched between jigs of a predetermined shape, heat-treated at a temperature of 1600° C., and deformed to obtain a temporary fixing substrate 21 (see FIGS. 5B and 5C).

The resulting temporarily fixed substrate and a silicon substrate having the same diameter were bonded with a thermosetting resin, and the presence or absence of crack generation at that time and the amount of bending after bonding were measured. However, a heat peeling adhesive was used for the peeling layer. Next, the silicon substrate was ground to a thickness of 0.1 mm, and the amount of curvature of the bonded body after grinding was measured.

However, the diameter (width) of the temporarily fixed substrate, the width of the peripheral flat plate portion, and the amount of curvature W were variously changed as shown in Table 1 by changing the molding conditions and the shape of the jig.

For each example, the presence or absence of cracks during bonding (visual observation), the amount of bending of the bonded body after bonding, and the amount of bending of the bonded body after grinding the silicon substrate were measured. Table 1 shows the measurement results.

(Comparative Examples 1 to 3)
An experiment similar to that of Example 1 was performed. However, in this example, the shape of the jig during the heat treatment was adjusted, and the temporary fixing substrate was not provided with the peripheral flat plate portion. Further, by changing the molding conditions and the shape of the jig, the diameter φ and the amount of curvature W of the temporarily fixed substrate were variously changed as shown in Table 2. The width of the outer peripheral plate portion is 0 mm.

For each example, the presence or absence of cracks during bonding (visual observation), the amount of bending of the bonded body after bonding, and the amount of bending of the bonded body after grinding the silicon substrate were measured. Table 2 shows the measurement results.

In the case of using the temporary fixing substrate of the comparative example having no peripheral flat plate portion, the amount of bending of the adhesive body is relatively large, and the amount of bending of the silicon substrate after polishing is also large.

When the temporary fixing substrate of the present invention is used, even if the amount of bending of the temporary fixing substrate is the same as that of the comparative example, the amount of bending of the adhesive body is small. Further, by setting the ratio of the width of the outer peripheral plate portion to 4 to 60%, the effect of the present invention became even more remarkable.

Further, each of the temporary fixing substrates of Examples 1 to 7 was produced, an electronic component chip was adhered thereto, and the substrate was sealed with a resin mold. Otherwise, the electronic component chip and the resin mold were separated from the temporary fixing substrate in the same manner as in Examples 1-7. Then, the resin mold was cut to obtain each electronic component chip. The presence or absence of cracks during bonding (visual observation) and the amount of bending of the bonded body after bonding were measured, and the same results as in Examples 1 to 7 were obtained.

Claims (13)

A temporary fixing substrate made of ceramics or glass, comprising a fixing surface for bonding and temporarily fixing at least one of a silicon substrate and an electronic component chip, and a bottom surface opposite to the fixing surface,
A temporary fixing substrate comprising an outer peripheral flat plate portion and a recessed deformation portion surrounded by the outer peripheral flat plate portion, wherein the fixing surface is a flat surface in the outer peripheral flat plate portion. 2. The temporary fixing substrate according to claim 1, wherein said ceramics is translucent alumina. 3. The temporary fixing substrate according to claim 1, wherein the width of said peripheral flat plate portion is 4 to 60% of the width of said temporary fixing substrate. The temporary fixing substrate according to any one of claims 1 to 3, characterized in that the amount of curvature of the concave deformation portion is 0.1 to 2.5 mm. A method comprising a step of bonding at least one of the silicon substrate and the electronic component chip to the fixing surface of the temporary fixing substrate according to any one of claims 1 to 4 to obtain an adhesive body. Temporary fixation method. 6. The method according to claim 5, further comprising a step of processing the silicon substrate of the adhesive body to thin the silicon substrate to form a silicon layer, and a step of separating the silicon layer from the temporary fixing substrate. Method. 7. The method of claim 6, comprising the step of providing an electronic component structure in said silicon layer. 6. The method according to claim 5, further comprising a step of covering the electronic component chip with a resin mold after bonding the electronic component chip to the fixing surface of the temporary fixing substrate. A step of bonding the silicon substrate to the fixing surface of the temporary fixing substrate according to any one of claims 1 to 4 to obtain an adhesive body;
a step of processing the silicon substrate of the adhesive body to thin the silicon substrate and form a silicon layer;
A method of manufacturing an electronic component, comprising: providing an electronic component chip in or on the silicon layer; and separating the silicon layer and the electronic component chip from the temporary fixing substrate. 10. The method of claim 9, further comprising dividing the silicon layer after separating the silicon layer from the temporary fixing substrate. 11. A method according to claim 9 or 10, characterized by the step of providing wiring in said silicon layer and connecting said wiring with said electronic component chip. A step of bonding the electronic component chip to the fixing surface of the temporary fixing substrate according to any one of claims 1 to 4 to obtain an adherent, and separating the electronic component chip from the temporary fixing substrate. A method for manufacturing an electronic component, comprising: 13. The method according to claim 12, further comprising a step of covering the electronic component chip with a resin mold after bonding the electronic component chip to the fixing surface of the temporary fixing substrate.

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