JP2016086073A - Semiconductor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method which can manufacture a semiconductor device including layered semiconductor elements which are unlikely to leave an air bubble between a semiconductor element and an adhesive layer and in which the semiconductor elements are layered via adhesive layers patterned with high accuracy.SOLUTION: A manufacturing method of a semiconductor device including a chip laminate 200(layered semiconductor elements) comprises: a coating process of forming a coating film on a wafer out of which semiconductor chips 20 (semiconductor elements) are cut; an exposure process of performing exposure processing; a development process of performing a development processing; a heating process of performing a heating treatment; a treatment process of performing etching and an ashing treatment; a back grind process of performing back grinding; a singulation process of performing a singulation process; and a mount process of obtaining the chip laminate 200 by laminating a cut individual piece 21 and a cut individual piece 22. A heat condition in the heating process is a temperature within a range of 80-170°C and a time within a range of 35-120 min.SELECTED DRAWING: Figure 5

Description

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

  The degree of integration of semiconductor devices has been increasing year by year in accordance with what is called Moore's law. However, in recent years, miniaturization of structures formed in semiconductor elements has approached physical limits, and the pace of high integration has slowed. In view of this, a method has been proposed in which the apparent integration degree is increased by stacking a plurality of semiconductor elements instead of increasing the density of one semiconductor element.

  When stacking semiconductor elements, an adhesive film for die bonding is disposed between the semiconductor elements, thereby bonding the elements. On the other hand, a buffer coat is provided between the semiconductor element and the adhesive in consideration of the generation of stress accompanying the curing shrinkage of the adhesive. Thereby, relaxation of stress concentration at the interface between the semiconductor element and the adhesive is achieved.

  In paragraphs 0003, 0078, and 0079 of Patent Document 1, in a stack package in which a plurality of semiconductor elements are stacked, a surface protective layer such as a buffer coat film is formed on a wafer, and this is bonded to a die bonding film (die attach film). Is disclosed.

  Recently, with the widespread use of mobile devices, there is an increasing demand for smaller and thinner semiconductor devices incorporated therein. Therefore, it is necessary to reduce the thickness of a semiconductor device in which a plurality of semiconductor elements are stacked. However, on the other hand, since there is a strong demand for further higher integration, it has been studied to increase the number of stacked semiconductor elements.

JP 2004-051970

  When a large number of semiconductor elements are stacked in this way, two layers of a buffer coat film that protects the surface of the semiconductor elements and a die bonding film that bonds the semiconductor elements to each other are interposed between the semiconductor elements. Therefore, there is a limit to reducing the thickness of the entire semiconductor device. In addition, since the two layers are interposed, the stacking process becomes complicated, and the problem increases as the number of stacked layers increases.

  Therefore, it is necessary to reduce the thickness of the entire semiconductor device and simplify the manufacturing process by reducing the number of members interposed between the semiconductor elements. However, since the element protection function of the buffer coat film and the bonding function of the die bonding film also include mutually contradicting elements, it is still insufficient to exert two functions in one layer.

  An object of the present invention is to provide a semiconductor capable of manufacturing a semiconductor device including a stacked semiconductor element in which bubbles do not easily remain between a semiconductor element and an adhesive layer and are stacked via an adhesive layer patterned with high accuracy. It is to provide a method for manufacturing an apparatus.

Such an object is achieved by the present inventions (1) to (8) below.
(1) A method of manufacturing a semiconductor device including a stacked semiconductor element formed by stacking a first semiconductor element and a second semiconductor element,
An application step of applying a liquid containing a photosensitive adhesive composition to one surface side of the first semiconductor element;
An exposure step of performing an exposure process on the coating film obtained by the coating step;
A development step of performing a development treatment on the coating film subjected to the exposure treatment;
A heating step of heating the coating film subjected to the development treatment;
A processing step of performing an etching process on the first semiconductor element provided with the heated coating film;
A mounting step of stacking the first semiconductor element and the second semiconductor element through the coating film to obtain the stacked semiconductor element;
Have
The method of manufacturing a semiconductor device, wherein heating conditions in the heating step are a temperature of 80 to 170 ° C. and a time of 35 to 120 minutes.

  (2) The method for manufacturing a semiconductor device according to (1), further including a back grinding process for grinding the other surface side of the first semiconductor element.

(3) In the application step, the liquid is applied to one surface side of a semiconductor substrate including the first semiconductor element and the second semiconductor element,
In the back grinding process, the other surface side of the semiconductor substrate is ground,
A dicing process is provided before or after the back grinding process, and the semiconductor substrate is diced to separate the semiconductor substrate, and the first semiconductor element and the second semiconductor element are separated from the semiconductor substrate. Furthermore, the manufacturing method of the semiconductor device according to (2).

(4) The photosensitive adhesive composition is
(A) an alkali-soluble resin;
(B) a photoacid generator;
(C) an epoxy compound;
(D) a phenolic compound;
The manufacturing method of the semiconductor device in any one of said (1) thru | or (3) containing.

  (5) The method for manufacturing a semiconductor device according to (4), wherein the (A) alkali-soluble resin is a cyclic olefin-based resin including a repeating unit having an acidic group.

  (6) The method for manufacturing a semiconductor device according to (5), wherein the cyclic olefin-based resin is a norbornene-based resin.

  (7) The method for manufacturing a semiconductor device according to any one of (4) to (6), wherein the (C) epoxy compound includes two or more glycidyl groups in a molecule.

  (8) The elastic modulus at 25 ° C. of the coating film after the heating step and before the treatment step is X [GPa], and the elastic modulus at 25 ° C. of the coating film after the treatment step is Y [GPa]. ], The method of manufacturing a semiconductor device according to (7), wherein the relationship of 0.7 ≦ X / Y ≦ 1.5 is satisfied.

  According to the method for manufacturing a semiconductor device of the present invention, since semiconductor elements can be bonded to each other while suppressing the remaining of bubbles at the interface between the adhesive layer and the semiconductor element after the development process, a highly reliable stacked semiconductor A semiconductor device including an element can be manufactured.

It is sectional drawing which shows an example of the semiconductor device manufactured by the manufacturing method of the semiconductor device of this invention. It is a figure for demonstrating embodiment of the manufacturing method of the semiconductor device of this invention. It is a figure for demonstrating embodiment of the manufacturing method of the semiconductor device of this invention. It is a figure for demonstrating embodiment of the manufacturing method of the semiconductor device of this invention. It is a figure for demonstrating embodiment of the manufacturing method of the semiconductor device of this invention.

  Hereinafter, a method for manufacturing a semiconductor device according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Semiconductor device>
First, prior to the description of the method for manufacturing a semiconductor device of the present invention, a semiconductor device manufactured by this manufacturing method will be described.

  FIG. 1 is a cross-sectional view showing an example of a semiconductor device manufactured by the method for manufacturing a semiconductor device of the present invention.

  A semiconductor device 10 shown in FIG. 1 is an example having a BGA (Ball Grid Array) type semiconductor package, a plurality of stacked semiconductor chips 20 (semiconductor elements), and an adhesive layer 601 for bonding the semiconductor chips 20 to each other. The package substrate 30 that supports the semiconductor chip 20, the adhesive layer 101 that bonds the semiconductor chip 20 and the package substrate 30, the mold part 50 that seals the semiconductor chip 20, and the solder that is provided below the package substrate 30 And a ball 80. Hereinafter, the configuration of each unit will be described in detail.

  The semiconductor chip 20 may be any kind of element, for example, a NAND (Not AND) flash memory, a memory element such as a DRAM (Dynamic Random Access Memory), an IC (Integrated Circuit), or an LSI (Large Scale Integration). Such an integrated circuit element is mentioned.

  The constituent material of the semiconductor chip 20 is not particularly limited, and examples thereof include single crystal materials such as silicon, silicon carbide, and compound semiconductors, polycrystalline materials, and amorphous materials.

The plurality of semiconductor chips 20 are stacked slightly shifted from each other in the in-plane direction, thereby forming a chip stacked body 200 (stacked semiconductor element). The semiconductor chips 20 are bonded to each other through an adhesive layer 601.
The adhesive layer 601 is also provided on the upper surface of the chip stack 200.

  A package substrate 30 shown in FIG. 1 is a build-up substrate including a core substrate 31, an insulating layer 32, a solder resist layer 33, a wiring 34, and a conductive via 35.

  Of these, the core substrate 31 is a substrate that supports the package substrate 30 and is made of, for example, a composite material in which a glass cloth is filled with a resin material.

  The insulating layer 32 is an interlayer insulating layer that insulates between the wirings 34 and between the wirings 34 and the conductive vias 35, and is made of, for example, a resin material. The solder resist layer 33 is a surface protective layer that protects the wiring formed on the outermost surface of the package substrate 30, and is made of, for example, a resin material.

  The wiring 34 and the conductive via 35 are each an electric signal transmission path, and are made of, for example, a metal material such as a simple substance or an alloy of Au, Ag, Cu, Al, and Ni.

  The solder ball 80 is electrically connected to the wiring 34, and functions as an electrode for connecting the wiring 34 to another electric circuit by being fused to an external electric circuit.

  A chip stack 200 formed by stacking a plurality of semiconductor chips 20 is placed on the upper surface of the package substrate 30. The chip stack 200 and the package substrate 30 are bonded by an adhesive layer 101.

  A part of the wiring 34 of the package substrate 30 is exposed on the upper surface of the package substrate 30, and the exposed portion and the electrode portion of each semiconductor chip 20 are connected by a bonding wire 70.

  The mold unit 50 shown in FIG. 1 is configured to cover the entire top surface of the package substrate 30 while covering the side surface and top surface of the chip stack 200. Thereby, the chip laminated body 200 can be protected from the external environment. Such a mold part 50 is comprised with various resin materials, such as an epoxy resin and a phenol resin, for example.

<Method for Manufacturing Semiconductor Device>
Next, an embodiment of a method for manufacturing a semiconductor device of the present invention will be described.

  2-5 is a figure for demonstrating embodiment of the manufacturing method of the semiconductor device of this invention, respectively. In the following description, for convenience of explanation, the upper part of FIGS. 2 to 5 is referred to as “upper” and the lower part is referred to as “lower”.

  The method for manufacturing a semiconductor device according to the present embodiment includes an application process for applying a liquid containing a photosensitive adhesive composition onto a wafer (semiconductor substrate), an exposure process for exposing the obtained coating film, and a development process. Development process for patterning the film, heating process for heating the coating film, processing process for etching the wafer provided with the heated coating film, back grinding process for grinding the back surface of the wafer, and dicing the wafer A dicing process for dividing the semiconductor chip into a plurality of semiconductor chips, a mounting process for picking up the semiconductor chip and mounting it on the package substrate, and then picking up another semiconductor chip and crimping it onto the semiconductor chip mounted first Have. Hereinafter, each process will be described sequentially.

[1] Application Step First, a wafer 201 (see FIG. 2A) for cutting out the semiconductor chip 20 is prepared, and a liquid containing the photosensitive adhesive composition is applied thereon (one surface side). Thereby, as shown in FIG. 2B, a coating film 601 a is formed on the wafer 201. The wafer 201 is formed with semiconductor circuits, electrode pads, and the like so as to include a plurality of semiconductor chips 20 in advance. That is, the wafer 201 is used for a so-called pre-process of the semiconductor manufacturing process. Therefore, a plurality of semiconductor chips 20 can be cut out by cutting the wafer 201 in steps described later and separating the wafer 201 into individual pieces.

  A coating method is not particularly limited, and examples thereof include a spin coating method, a spray coating method, an ink jet method, a roll coating method, and a printing method.

  If necessary, the applied liquid (liquid film) may be heated and dried. In this case, the heating temperature is preferably 70 to 160 ° C, and more preferably 80 to 150 ° C. Moreover, although heating time is suitably set according to heating temperature, it is preferable that it is 5 seconds-30 minutes, and it is more preferable that it is 10 seconds-15 minutes.

  The liquid containing the photosensitive adhesive composition is prepared by appropriately adding a solvent or the like that dissolves the liquid to the photosensitive adhesive composition. Moreover, it is preferable that the solvent to be used is a solvent that can be volatilized and removed when heated in a process described later. Specifically, toluene, xylene, benzene, dimethylformamide, tetrahydrofuran, ethyl cellosolve, ethyl acetate, N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether , Diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, methyl-1,3-butylene glycol acetate, 1,3 -Butylene glycol-3-monomethyl ether, methyl pyruvate , Ethyl pyruvate, include methyl 3-methoxy propionate or the like, can be used singly or in combination of two or more of them. Among these, a solvent containing any of propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, γ-butyrolactone and cyclohexanone is preferably used because it is highly soluble and easily removed by volatilization.

[2] Exposure Step Next, an exposure process is performed on a desired region of the coating film 601a formed on the wafer 201 (see FIG. 2C). As a result, a photoreaction occurs in the coating film 601a in the exposure region, and patterning is potentially performed (latent image is formed).

  In order to perform an exposure process on a desired region of the coating film 601a, as shown in FIG. 2C, a mask 4 provided so as to be in contact with the coating film 601a can be used.

  As light used for the exposure process, electromagnetic waves and particle beams having various wavelengths are used. For example, ultraviolet rays such as i-rays, visible rays, lasers, X-rays, electron beams, and the like are used. Among these, ultraviolet rays or visible rays having a wavelength of about 200 to 700 μm are preferably used. The exposure process can be performed in, for example, an air atmosphere, an inert gas atmosphere, or a reduced pressure atmosphere.

  In this exposure step, a mask provided separately from the coating film 601a may be used instead of the mask 4 provided in contact with the coating film 601a. Note that the use of a mask can be omitted when a highly directional material such as an X-ray or an electron beam is used.

Although the exposure amount in the exposure process is appropriately set according to the thickness of the coating film 601a, the sensitivity of the photosensitive adhesive composition, and the like, it is preferably about 30 to 3000 mJ / cm ² as an example.

[3] Development Step Next, the coating film 601a subjected to the exposure processing is subjected to development processing. Thereby, the coating film 601a in the exposed portion is removed, and desired patterning is performed as shown in FIG. By such development processing, for example, a pad for connecting the bonding wire 70 to the semiconductor chip 20 can be exposed, or the coating film 601a on the dicing line that is to be cut in a dicing process described later can be removed. .

  In the development process, the developer is brought into contact with the coating film 601a subjected to the exposure process. Thereby, the coating film 601a in the exposed portion is dissolved in the developer and removed. Thereby, the opening part 601b is formed in the coating film 601a. Developers include, for example, alkali metal carbonates, alkali metal hydroxides, alkali developers such as tetraammonium hydroxide, organic developers such as dimethylformamide, N-methyl-2-pyrrolidone, and the like. In particular, an alkali developer is preferably used. Alkali developers have the characteristics that the burden on the environment is small and residues are not easily generated.

  Moreover, as a supply method of a developing solution, systems, such as a spray, a paddle, immersion, and an ultrasonic wave, are mentioned, for example.

  In the present embodiment, the coating film 601a has a so-called positive-type photosensitivity, but the coating film 601a may have a so-called negative-type photosensitivity.

[4] Heating Step Next, the coating film 601a subjected to the development processing is heated (see FIG. 2 (e)). Thereby, predetermined | prescribed hardening reaction arises in the photosensitive adhesive composition which comprises the coating film 601a, and moderate adhesiveness expresses in the coating film 601a.

  The heating temperature of the coating film 601a is 80 to 170 ° C., preferably 120 to 160 ° C. On the other hand, the heating time is appropriately set according to the heating temperature, but is 35 to 120 minutes, preferably 40 to 100 minutes. Thereby, in the mounting process described later, the semiconductor chip 20 is suppressed while the bubbles remain between the adhesive layer 601 formed by separating the coating film 601a and the semiconductor chip 20 formed by separating the wafer 201. They can be bonded together. That is, by performing the heat treatment under the above-described conditions in this step, a reaction occurs in the coating film 601a, and mechanical properties such as elastic modulus are optimized, and sufficient for etching treatment and ashing treatment in the treatment step described later. Tolerance is given. For this reason, when the adhesive layer 601 and the semiconductor chip 20 are brought into close contact with each other in the mounting process, bubbles are hardly left at the interface between the adhesive layer 601 and the semiconductor chip 20, and the adhesive force between the semiconductor chips 20 is enhanced. The semiconductor chips 20 can be bonded more reliably. Therefore, finally, the semiconductor device 10 including the highly reliable chip stack 200 can be obtained.

  In addition, the adhesive layer 601 formed from such a coating film 601a exhibits relatively high solubility in an organic solvent. For this reason, for example, even when it is necessary to remove the coating film 601a after forming the coating film 601a on the wafer 201, the coating film 601a is efficiently dissolved while suppressing the generation of residues (residues). Can be removed. Thus, the wafer 201 can be used again (reworked) without wasting the wafer 201, and the process yield can be improved.

  In addition, since a reaction in the coating film 601a is reduced when the heating temperature is lower than the lower limit value, the elastic modulus is reduced. Or etching tolerance and ashing tolerance fall. For this reason, bubbles are easily left behind at the interface between the adhesive layer 601 and the semiconductor chip 20 in the mounting step, or the adhesion between the adhesive layer 601 and the semiconductor chip 20 is reduced. On the other hand, when the heating temperature exceeds the upper limit, the reaction in the coating film 601a becomes excessive, and the elastic modulus becomes excessive. For this reason, the air bubbles left at the interface between the adhesive layer 601 and the semiconductor chip 20 cannot be expelled (discharged) outside the interface in the mounting process, and as a result, the air bubbles remain, or the adhesive layer 601 and the semiconductor chip 20 Adhesiveness with 20 may decrease. Moreover, the solubility with respect to the organic solvent of the coating film 601a falls, and what is called rework property falls.

[5] Processing Step Next, an etching process is performed on the wafer 201 provided with the heated coating film 601a. Thereby, the coating film 601a provided with the opening 601b functions as an etching mask, and an etching process is selectively performed on a region corresponding to the opening 601b in the surface (upper surface) of the wafer 201. As a result, when a passivation film is formed on the surface of the wafer 201, it can be removed and a pad for connecting the bonding wire 70 can be exposed.

Examples of the etching process include plasma etching (dry etching) in which etching is performed by supplying plasma as shown in FIG. 3 (f), various wet etching processes, and the like. Among these, the plasma etching treatment can be performed under generally known conditions. For example, fluorine compound gas (CF ₄ , CHF ₃ ), fluorine compound gas (CF ₄ , CHF ₃ ) and oxygen Using gas mixture with gas (O ₂ ), mixture gas of fluorine compound gas (CF ₄ , CHF ₃ ) and argon gas (Ar), output is 200 to 2000 W, time is 0.2 to 15 minutes, gas flow rate Can be 50-1000 sccm.

  Thereafter, an ashing process is performed as necessary. Thereby, the process residue etc. which generate | occur | produced by the etching process can be removed, and the coating-film 601a surface and the pad surface can be cleaned. As a result, the adhesive force of the adhesive layer 601 described later can be increased, and the bonding force of the bonding wire 70 to the pad can be increased.

Examples of the ashing treatment include plasma treatment and wet treatment using a chemical. Among these, the conditions for performing the plasma treatment are, for example, oxygen gas (O ₂ ), a mixture gas of oxygen gas (O ₂ ) and argon gas (Ar), or the like as the treatment gas, the output is 200 to 2000 W, and the treatment time. Is 0.2 to 15 minutes, and the gas flow rate is 50 to 1000 sccm.

[6] Back Grinding Step Next, as shown in FIG. 3G, a back grind film 90 is pasted on the coating film 601a. The back grind film 90 supports the wafer 201 during the back grind process, and suppresses occurrence of defects such as chipping and cracking in the wafer 201.

Next, the back surface (the other surface side) of the wafer 201 is ground (back grinding process). Thereby, the broken line portion in FIG. 3H is removed, and the thickness of the wafer 201 can be reduced. As a result of this grinding, the thickness of the wafer 201 is reduced to about 20 to 100 μm although it varies depending on the original thickness.
For this grinding, for example, a device called a back grinding wheel is used.

  In addition, the coating film 601a heated on the above heating conditions can cut out the contact bonding layer 601 which expresses sufficient adhesive force between the semiconductor chips 20. In addition, the coating film 601 a heated under the heating conditions as described above exhibits sufficient adhesive force to the back grind film 90. Therefore, by sticking the back grind film 90 on the coating film 601a, the back grind film 90 can reliably support the coating film 601a and the wafer 201, and the above-described back grinding process can be performed with high accuracy. it can. For this reason, it is possible to realize the semiconductor chip 20 in which the thickness variation is small and the inclination or the like hardly occurs when stacked.

  In the case of this embodiment, the coating film 601a is formed on the wafer 201 subjected to the back grinding process, and the back grinding process is performed in that state. As described above, the coating film 601a has mechanical characteristics that can reliably bond the semiconductor chips 20 to each other. Therefore, the coating film 601a not only intervenes between the wafer 201 and the back grind film 90, but also has a function of mechanically supporting the wafer 201. In addition, since the coating film 601a is formed on the wafer 201 in a liquid state and then cured, the adhesion with the wafer 201 is good. Therefore, by performing the back grinding process on the wafer 201 in a state where the coating film 601a is formed, a more uniform process can be performed.

[7] Dicing Step Next, the wafer 201 is subjected to a dicing process. As a result, the wafer 201 is cut into a plurality of semiconductor chips 20 and separated into individual pieces.

  In the dicing process, the wafer 201 is attached to a dicing die attach film or a dicing film. This dicing die attach film or dicing film fixes the wafer 201 during the dicing process.

  FIGS. 3 (i1) and 3 (i2) are diagrams showing examples in which a dicing film 100a is attached to the back side of the wafer 201 ground in the back grinding process. FIG. 3 (i1) illustrates a wafer 201 and the like for cutting out the semiconductor chip 20 used for the lowermost layer (the layer closest to the package substrate 30) of the chip stack 200, while FIG. i2) illustrates the wafer 201 and the like for cutting out the semiconductor chip 20 used in a portion other than the lowermost layer of the chip stack 200.

  In FIG. 3 (i1), the dicing die attach film 100 which is a laminated body of the dicing film 100a and the die attach film 100b is affixed on the back surface of the wafer 201, while in FIG. The dicing film 100a is affixed on the back surface.

  Next, as shown in FIGS. 4 (j1) and 4 (j2), the back grind film 90 is peeled off from the coating film 601a.

  Next, a dicing process is performed on the wafer 201 provided with the coating film 601a. In the dicing process, as shown in FIGS. 4 (k1) and 4 (k2), the dicing blade 110 reaches the dicing film 100a. As a result, the coating film 601a, the wafer 201, and the die attach film 100b are separated into individual pieces, and the adhesive layer 601, the semiconductor chip 20 (first semiconductor element), and the adhesive layer 101 are laminated as shown in FIG. 4 (k1). The individual piece 21 is cut out. Similarly, the coating film 601a and the wafer 201 are separated into individual pieces, and as shown in FIG. 4 (k2), the individual piece 22 formed by laminating the adhesive layer 601 and the semiconductor chip 20 (second semiconductor element) is cut out.

  In the present embodiment, a case where a wafer 201 (semiconductor substrate) configured to include a plurality of semiconductor chips 20 is diced to cut out the plurality of semiconductor chips 20 is described. The present invention is not limited to such a case. For example, the present invention can also be applied to a case where a plurality of semiconductor chips 20 that are separated into pieces in advance are used. In this case, the dicing process can be omitted. When the wafer 201 and the semiconductor chip 20 are thin from the beginning, the back grinding process can be omitted.

  Further, the process order of the back grinding process and the dicing process is not limited to the order described above, and may be reversed. That is, the back grinding process may be performed after the wafer 201 is subjected to the dicing process.

  In addition, the semiconductor device 10 can be efficiently manufactured by performing the back grinding process and the dicing process on the wafer 201 configured to include the plurality of semiconductor chips 20 in this way.

[8] Mounting Process FIG. 4 (L1) and FIG. 4 (L2) are diagrams showing an example in which the cut piece 21 and the piece 22 are picked up by the collet 121 of the bonding apparatus 120, respectively.

  First, the individual piece 21 is picked up by the collet 121 of the bonding apparatus 120 and is crimped (mounted) on the package substrate 30. At this time, the back surface of the semiconductor chip 20 and the package substrate 30 are bonded via an adhesive layer 101 as shown in FIG. In addition, this contact bonding layer 101 may be comprised with the photosensitive adhesive composition mentioned later, for example besides the piece of the die attach film 100b.

  Then, the piece 22 is crimped | bonded on the piece 21 mounted previously. Thereby, as shown in FIG. 5B, two semiconductor chips 20 can be stacked via the adhesive layer 601. Thereafter, by repeating this step, as shown in FIG. 5C, a chip stack 200 in which a large number of semiconductor chips 20 are stacked is obtained. At this time, by stacking the semiconductor chips 20 while shifting the positions thereof, a region to which the bonding wire 70 is connected (a region corresponding to the opening 601b of the coating film 601a) can be secured.

  Further, when the semiconductor chip 20 is mounted, the adhesive layer 601 is heated. Thereby, sufficient adhesive force is expressed in the adhesive layer 601, and the semiconductor chips 20 can be firmly bonded to each other. In this case, the heating temperature is preferably about 30 to 150 ° C. Moreover, it is preferable that the crimping | compression-bonding load at the time of mounting is about 0.1-100N, and the crimping | compression-bonding time is about 0.1-10 seconds.

  Thereafter, the electrode portion of each semiconductor chip 20 and the exposed portion of the wiring 34 of the package substrate 30 are connected by a bonding wire 70 as shown in FIG.

  And the semiconductor device 10 shown in FIG. 1 is obtained by shape | molding the mold part 50 so that the chip laminated body 200 may be covered.

  The molding of the mold part 50 can be performed by, for example, using a transfer molding machine and injecting a sealing material into the molding die. In that case, it is preferable that the temperature of the mold is about 130 to 250 ° C., the injection pressure is about 3 to 10 MPa, and the holding time after injection is about 10 seconds to 10 minutes.

  After mold release, the molded part 50 and the adhesive layer 601 can be finally cured by heating the molded body as necessary. In this case, the heating temperature is preferably about 130 to 250 ° C., and the heating time is preferably about 10 minutes to 10 hours.

<Photosensitive adhesive composition>
Next, the photosensitive adhesive composition constituting the adhesive layer 601 will be described.

≪Physical properties≫
The adhesive layer 601 that bonds the semiconductor chips 20 to each other is made of a cured product of the photosensitive adhesive composition. Such an adhesive layer 601 is provided with sufficient adhesiveness and stress relaxation properties despite the single layer structure. Therefore, it is possible to obtain a highly reliable chip stack 200 in which stress concentration between layers caused by a difference in thermal expansion and the like is reduced while avoiding a significant increase in the total thickness of the chip stack 200. As a result, a low-profile and highly reliable semiconductor device 10 can be obtained. Such a semiconductor device 10 has a very small internal volume, such as a mobile device, and is particularly useful in an electronic device that is used while being carried. That is, it is useful in that it contributes to the reduction in size, thickness, and weight of the electronic device and that the function of the semiconductor device 10 is hardly impaired even when the electronic device is dropped or swung.

  The cured product of the photosensitive adhesive composition, that is, the elastic modulus of the adhesive layer 601 is preferably 2.0 to 3.5 GPa at 25 ° C. Moreover, it is preferable that the elasticity modulus of the state before hardening of a photosensitive adhesive composition is 70 to 120% of the elasticity modulus in 25 degreeC in 25 degreeC. Moreover, it is preferable that the adhesive force with respect to the semiconductor chip 20 of the photosensitive adhesive composition in the state before the hardening used for the etching process and the ashing process is 20.0-200.0N at 25 degreeC.

  Such a photosensitive adhesive composition has an elastic modulus in a state before curing within a predetermined range with respect to the elastic modulus after curing, for example, the photosensitive adhesive composition before curing is significantly deformed. Or the risk of flowing out is reduced. For this reason, it is possible to improve the alignment accuracy when the semiconductor chips 20 are stacked. Furthermore, since the amount of change in elastic modulus before and after curing is relatively small, the amount of shrinkage associated with photosensitivity can also be reduced, and the stress generated at the interface with the semiconductor chip 20 due to curing shrinkage can be reduced. it can. From this viewpoint, it contributes to improving the reliability of the chip stack 200.

  On the other hand, the photosensitive adhesive composition in a state before being subjected to the etching process and the ashing process has a sufficient adhesion force required for die bonding to the semiconductor chip 20. For this reason, the adhesive layer 601 that bonds the semiconductor chips 20 to each other securely fixes the semiconductor chips 20 to each other and contributes to improving the reliability of the chip stack 200.

  According to the photosensitive adhesive composition that satisfies the above conditions, it is possible to realize the adhesive layer 601 that achieves both sufficient adhesiveness and stress relaxation properties. In other words, since the adhesive layer 601 combines the element protection function (buffer coating function) of the buffer coating film and the bonding function (die bonding function) of the die bonding film with one layer, the reliability is lowered. It is possible to form the chip stacked body 200 without reducing the thickness of the chip stacked body 200 as compared with the conventional structure using two layers. Further, as the chip stack 200 is made thinner, the volume of the mold part 50 can be reduced and the bonding wire 70 can be shortened, thereby contributing to weight reduction and cost reduction.

  The elastic modulus (25 ° C.) of the cured product of the photosensitive adhesive composition is more preferably about 2.2 to 3.2 GPa, and further preferably about 2.4 to 3.0 GPa. If the elastic modulus of the cured product is below the lower limit, depending on the composition of the photosensitive adhesive composition, the adhesive force of the adhesive layer 601 may be reduced, and the interface with the semiconductor chip 20 may be peeled off, or the mold part When a filler is contained in 50, the filler may penetrate the adhesive layer 601 and adversely affect the semiconductor chip 20. On the other hand, when the elastic modulus of the cured product exceeds the upper limit, depending on the composition of the photosensitive adhesive composition, the flexibility of the adhesive layer 601 is reduced, so that the stress relaxation property is reduced. Residual stress caused by the thermal stress and local concentration of the thermal stress due to the difference in thermal expansion between the semiconductor chip 20 and the adhesive layer 601 cannot be alleviated, causing the semiconductor chip 20 to crack or adhere to the semiconductor chip 20. There is a risk of peeling between the layer 601 and the like.

  The elastic modulus of the cured product is, for example, an ultra-micro hardness meter ENT-1000 (manufactured by Elionix Co., Ltd.) with a measurement temperature of 25 ° C., a load of 2 mN, a holding time of 1 second, and a Berkovich indenter (triangular pyramid, It can be obtained by measuring in accordance with ISO14577 using the opposite ridge angle (115 °).

  Moreover, the elasticity modulus of the hardened | cured material of a photosensitive adhesive composition can be calculated | required as an elasticity modulus of the coating film 601a after a mounting process.

The elastic modulus (25 ° C.) of the photosensitive adhesive composition before curing is more preferably 75 to 115% of the elastic modulus at 25 ° C. of the cured product, and further preferably 80 to 110%. The In addition, when the elastic modulus in a state before curing is lower than the lower limit value, although the tackiness is increased, the film of the photosensitive adhesive composition is easily deformed. For example, the semiconductor chip 20 is temporarily disposed via the film. When it does, there exists a possibility that the position may become easy to shift | deviate or a photosensitive adhesive composition may flow out. On the other hand, when the elasticity modulus in the state before hardening exceeds the said upper limit, adhesiveness falls and there exists a possibility that it may become difficult to arrange | position the semiconductor chip 20 temporarily.
In addition, the elasticity modulus of the state before hardening can be measured similarly to the elasticity modulus of hardened | cured material.

  Moreover, the elasticity modulus of the state before hardening of a photosensitive adhesive composition can be calculated | required as an elasticity modulus of the coating film 601a after a process process and before a mounting process.

  On the other hand, the adhesive force (25 ° C.) of the photosensitive adhesive composition to the semiconductor chip 20 in a state before being subjected to etching treatment and ashing treatment is more preferably 30 to 180 N, and further preferably 40 to 160 N. It is said. In addition, when the adhesive force is less than the lower limit value, the reliability of the semiconductor device 10 may be reduced due to, for example, the bonding between the semiconductor chips 20 being released. Moreover, there is a possibility that bubbles may easily enter the interface between the adhesive layer 601 and the semiconductor chip 20. On the other hand, when the adhesive force exceeds the upper limit, if bubbles enter the interface between the adhesive layer 601 and the semiconductor chip 20, it is difficult to remove them, and there is a risk that bubbles may remain at the interface.

  In addition, the adhesive force with respect to the semiconductor chip 20 is obtained by bonding the semiconductor chips 20 to each other through the photosensitive adhesive composition in a state before being subjected to the etching process and the ashing process, and then, for the semiconductor chip stacked body 200. Using a universal bond tester Dage4000 (manufactured by Daisy Japan Co., Ltd.), the semiconductor chip is pushed in the horizontal direction (in-plane direction of the semiconductor chip 20) with the share tool from the side (side surface) of the semiconductor chip 20, and between the semiconductor chips 20 It is calculated | required as intensity | strength (die shear strength) when a joint surface is fractured.

  In addition, the adhesive strength of the photosensitive adhesive composition to the semiconductor chip 20 in the state before being subjected to the etching treatment and the ashing treatment is the coating film after the treatment step after the etching treatment and the ashing treatment and before the mounting step. It can be obtained as the adhesive force of 601a to the semiconductor chip 20.

The etching process is, for example, a process of removing a passivation film on the surface of the semiconductor chip 20 and exposing a pad for connecting the bonding wire 70, and specifically, a fluorine compound gas (CF) as a gas. ₄ ) Using a mixed gas of argon gas (Ar) and oxygen gas (O ₂ ), with an output of 2500 W, a time of 6 minutes, and a CF ₄ flow rate / Ar flow rate / O ₂ flow rate of 200 sccm / 200 sccm / 50 sccm. The etching process to perform is mentioned.

The ashing process is a process for removing, for example, processing residues generated by the etching process and cleaning the surface of the adhesive layer 601 and the pad surface. Specifically, oxygen gas (O ₂ ) is used. The plasma treatment is performed under the conditions that the output is 600 W, the time is 12 minutes, and the O ₂ flow rate is 200 sccm.

  In addition, since such an etching process and an ashing process may accelerate deterioration of an organic material, when the adhesive layer 601 has low etching resistance and ashing resistance, the semiconductor chips 20 may not be sufficiently bonded to each other. There is.

  On the other hand, since the adhesive layer 601 formed using the photosensitive adhesive composition has sufficient etching resistance and ashing resistance, after such etching processing and ashing processing, However, the decrease in the adhesive strength is suppressed, and as a result, the adhesive strength as described above is exhibited. Therefore, such a photosensitive adhesive composition does not need to consider a decrease in adhesiveness in various treatments in the adhesion process, and thus can simplify the manufacturing process and reduce costs. Useful in terms.

  In addition, the elastic modulus of the photosensitive adhesive composition is preferably such that the change before and after the treatment step is within a certain range. In other words, the heating condition in the heating process that is thought to affect the resistance to the processing process (etching resistance and ashing resistance) is a range in which the elastic modulus of the photosensitive adhesive composition changes within a certain range before and after the processing process. It is preferable to set appropriately so as to be within.

  Specifically, the elastic modulus (25 ° C.) after the heating step and before the processing step of the photosensitive adhesive composition is X [GPa], and the elastic modulus (25 ° C.) after the processing step is Y [GPa]. Then, it is preferable to satisfy the relationship of 0.7 ≦ X / Y ≦ 1.5, and it is more preferable to satisfy the relationship of 0.8 ≦ X / Y ≦ 1.3. Since the change in elastic modulus before and after the treatment process satisfies the above relationship, the coating film 601a composed of the photosensitive adhesive composition has sufficient mechanical properties to maintain the patterned shape. The semiconductor chip 20 has sufficient adhesiveness to bond the semiconductor chips 20 together. That is, since the treatment process involves an etching process or an ashing process, the coating film 601a easily deteriorates. However, when the elastic modulus satisfies the above relationship before and after the treatment process, the coating film 601a is patterned. It sufficiently functions as the adhesive layer 601 in the mounting process, while maintaining a sufficient shape. For this reason, when the change in the elastic modulus before and after the treatment process satisfies the above relationship, the coating film 601a composed of such a photosensitive adhesive composition functions as an etching mask and an adhesive layer 601. And can be compatible.

  Note that the processing step in the above-mentioned regulation is an etching process and an ashing process that satisfy the above-described processing conditions.

  Moreover, it is preferable that the minimum melt viscosity in the range of 100-200 degreeC is 20-500 Pa.s in the state before the hardening of the photosensitive adhesive composition. Since such a composition is excellent in wettability with respect to the semiconductor chip 20, it becomes difficult for voids or the like to be generated in the adhesive layer 601. Accordingly, since a uniform adhesive layer 601 with little variation in physical properties can be formed, when the semiconductor chips 20 are bonded to each other via the adhesive layer 601, it is difficult to cause local concentration of stress, and cracks are generated in the semiconductor chip 20. In addition, the occurrence of peeling between the semiconductor chip 20 and the adhesive layer 601 can be suppressed. In addition, the melt viscosity before hardening of a photosensitive adhesive composition can be measured with a rheometer. Moreover, the melt viscosity in the state before hardening of a photosensitive adhesive composition can be calculated | required as a melt viscosity of the coating film 601a after a process process and before a mounting process.

  The minimum melt viscosity before curing is more preferably 25 to 400 Pa · s, and further preferably 30 to 300 Pa · s.

  In addition, the photosensitive adhesive composition has a certain degree of tackiness when in a state before being cured, and the tackiness can be reduced by applying UV irradiation treatment to the photosensitive adhesive composition. . Therefore, it can be said that such a photosensitive adhesive composition can control its tackiness by the presence or absence of UV irradiation treatment.

  Specifically, the photosensitive adhesive composition is in a state before being cured and after being subjected to the etching process and the ashing process described above, the UV peeling type back grind film 90 is Preferably, it exhibits an adhesive strength of 3.0 N / 25 mm or more at 25 ° C. Such a photosensitive adhesive composition is capable of exhibiting sufficient adhesive force to the back grind film 90 even after being subjected to a treatment that promotes deterioration of the organic material such as an etching treatment or an ashing treatment. Therefore, for example, when the back grinding process is performed on the wafer 201 on which the coating film 601a of the photosensitive adhesive composition is formed, the wafer 201 can be securely fixed, and the accuracy of the back grinding process can be further improved. it can.

  The adhesive strength is more preferably 3.5 N / 25 mm or more and 10.0 N / 25 mm or less.

  In addition, the adhesive strength is such that a UV peeling type back grind film 90 (width 25 mm, length 75 mm) is bonded so that the adhesive surface is in contact with the coating film 601a of the photosensitive adhesive composition, and the measurement temperature is 25. And then pulling one end in the longitudinal direction of the back grind film 90 so that the peel angle is 180 °, and the peeling speed is 10.0 ± 0.2 mm / s. When the back grind film 90 is peeled off from the coating film 601a, the average value of the load required for the peeling (180 ° peeling adhesive strength, unit: N / 25 mm, JIS Z 0237 compliant) can be obtained. .

  On the other hand, the photosensitive adhesive composition is in a state before being cured and after being subjected to the UV irradiation treatment, preferably 0 ° C. at 50 ° C. with respect to the UV peeling type back grind film 90. It exhibits an adhesive strength of 5 N / 25 mm or less. Such a photosensitive adhesive composition can sufficiently reduce the adhesive strength to the back grind film 90 by UV irradiation treatment. For example, the back grind film 90 is applied to the coating film 601a of the photosensitive adhesive composition. When the back grind film 90 is peeled off from the coating film 601a of the photosensitive adhesive composition, the back grind film 90 is smoothly peeled without exerting a large load on the coating film 601a. Can do. In addition, since the back grind film 90 can be peeled without impairing the adhesion between the coating film 601a and the semiconductor chip 20, for example, when picking up the separated semiconductor chip 20 after dicing, It is possible to prevent problems such as chipping of the chip 20 from occurring.

  Further, by reducing the adhesive strength of the coating film 601a as described above, for example, the photosensitive adhesive composition adheres to the dicing blade 110 in the dicing process, or the photosensitive adhesive composition adheres to the collet 121 in the mounting process. It can suppress adhering. As a result, it is possible to suppress the occurrence of dicing failure and pickup failure.

  The adhesive strength is more preferably 0.05 N / 25 mm or more and 0.40 N / 25 mm or less.

In addition, the UV irradiation process is a process of irradiating light having a wavelength of 365 nm so that the integrated light amount is 600 mJ / cm ² .

  Further, the UV peeling type back grind film 90 used in the above regulations is made of acrylic resin.

  In addition, the measurement of the adhesive force at 50 degreeC with respect to the back grind film 90 of the state after using for the UV irradiation process of the coating film of the photosensitive adhesive composition was used for the etching process and the ashing process mentioned above. It can carry out by the method similar to the measurement of the adhesive force in 25 degreeC with respect to the back grind film 90 of a back state.

≪Composition≫
The photosensitive adhesive composition may be any composition as long as the composition can change the solubility in an alkaline aqueous solution and / or an organic solvent by light irradiation and can exhibit adhesiveness. As an example, (A) an alkali-soluble resin, (B) a photoacid generator, (C) an epoxy compound, and (D) a phenol compound are included.

Hereinafter, each material constituting the photosensitive adhesive composition will be described in detail.
<(A) Alkali-soluble resin>
(A) The alkali-soluble resin is a material that becomes a base material of the adhesive layer 601. Moreover, the photosensitive adhesive composition can enhance the adhesive force (adhesive force) of the adhesive layer 601 to the semiconductor chip 20 by including (A) an alkali-soluble resin. Therefore, the semiconductor chips 20 can be more firmly bonded to each other by the adhesive layer 601. Furthermore, since (A) the alkali-soluble resin is included, the coating film 601a becomes soluble in an alkali developer, so that it is possible to reduce the environmental load in the development process.

  Specific examples of the (A) alkali-soluble resin include, for example, phenolic resins, acrylic resins, cyclic olefinic resins, polyamide resins, and the like, and one or more of these are used in combination. be able to. Among these, a cyclic olefin resin is particularly preferable. Examples of the cyclic olefin-based resin include norbornene-based resins and benzocyclobutene-based resins. Among these, norbornene-based resins are preferable. By using a photosensitive adhesive composition containing a cyclic olefin-based resin, an adhesive layer 601 that is particularly excellent in adhesive strength to the semiconductor chip 20 can be obtained. In particular, the adhesive force of the adhesive layer 601 to the semiconductor chip 20 can be further increased by using a photosensitive adhesive composition containing a norbornene-based resin. Moreover, since norbornene-type resin has high hydrophobicity, the adhesive layer 601 which cannot produce the dimensional change by water absorption etc. easily can be formed by using the photosensitive adhesive composition containing norbornene-type resin.

  Moreover, when (A) alkali-soluble resin is cyclic olefin resin, it is preferable that cyclic olefin resin has at least one repeating unit (1st repeating unit) which has an acidic group.

  The first repeating unit is a structure in which a substituent having an acidic group is bonded to a structure derived from a cyclic olefin (cyclic olefin monomer) as a main skeleton.

  As structures derived from cyclic olefins, monocyclic compounds such as cyclohexene and cyclooctene, norbornene, norbornadiene, dicyclopentadiene, dihydrodicyclopentadiene, tetracyclododecene, tricyclopentadiene, dihydrotricyclopentadiene, tetracyclopentadiene, Examples include structures derived from polycyclic compounds such as dihydrotetracyclopentadiene. Among these, a structure derived from norbornene is particularly preferable. With the structure derived from norbornene, the adhesive force of the adhesive layer 601 to the semiconductor chip 20 can be further increased. A photosensitive adhesive composition containing (A) an alkali-soluble resin having a structure derived from norbornene is preferable because it is excellent in heat resistance and also excellent in flexibility after curing.

Examples of the substituent having an acidic group include a substituent having a carboxyl group, a phenolic hydroxyl group, —C (OH) — (CF ₃ ) ₂ , —N (H) —S (O) ₂ —CF _{3, and the} like. Among these, a substituent having any of a carboxyl group and —C (OH) — (CF ₃ ) ₂ is preferable. When cyclic olefin resin contains the substituent which has such an acidic group, the solubility with respect to the alkaline developing solution of the photosensitive adhesive composition can be improved. Therefore, in the manufacture of a semiconductor device, the undissolved residue of the photosensitive adhesive composition after development can be reduced, and the patterning property during development can be further improved.

  Therefore, the first repeating unit is particularly preferably at least one selected from the group consisting of the following formula (2) and the following formula (3). By including the first repeating unit having such a structure, the adhesiveness of the adhesive layer 601 to the semiconductor chip 20 can be further increased. Moreover, the solubility with respect to the alkaline developing solution of the photosensitive adhesive composition can be made higher.

  In the above formula (2) and the above formula (3), x and y are each preferably an integer of 0 or more and 10 or less, and more preferably an integer of 1 or more and 5 or less. Thereby, the adhesive layer 601 which can adhere | attach the semiconductor chips 20 more firmly can be obtained.

  The cyclic olefin-based resin may be one having at least one first repeating unit, but preferably has two or more different first repeating units, and the above formula (2) and the above It is more preferable to have both first repeating units of formula (3). Thereby, the adhesiveness of the adhesive layer 601 to the semiconductor chip 20 can be further increased, and the solubility of the photosensitive adhesive composition in the alkaline developer can be further increased.

  The content of the first repeating unit in the cyclic olefin-based resin can be determined in consideration of the solubility of the photosensitive adhesive composition in an alkaline developer, and is, for example, 10 to 80 mol%. It is preferable that it is 20 to 70 mol%. When the content of the first repeating unit is less than the lower limit, it may be difficult to sufficiently develop solubility in an alkaline developer. If the content of the first repeating unit exceeds the upper limit, depending on the type of the first repeating unit, the characteristics of the cyclic olefin resin other than the first repeating unit may be buried. There is.

  The acidic group in the cyclic olefin resin is preferably 0.001 to 0.01 mol per 1 g of the polymer. More preferably, it is 0.0015 to 0.006 mol. Thereby, especially the solubility with respect to the alkaline developing solution of the photosensitive adhesive composition can be improved.

  Furthermore, it is preferable that cyclic olefin resin has a 2nd repeating unit different from the 1st repeating unit mentioned above.

  The second repeating unit is a structure in which a substituent different from the substituent of the first repeating unit is bonded to the structure derived from the cyclic olefin as the main skeleton.

  As the main skeleton of the second repeating unit, those mentioned in the first repeating unit can be used, and among these, in particular, from norbornene from the viewpoint of heat resistance and flexibility after curing. The structure is preferably The main skeletons of the first and second repeating units may be different from each other, but are preferably the same. In particular, the main skeletons of the first and second repeating units are preferably structures derived from norbornene. Thereby, while being able to raise the adhesive force with respect to the semiconductor chip 20 of the contact bonding layer 601, the elasticity modulus of the contact bonding layer 601 can be lowered | hung moderately. Therefore, the semiconductor chip 20 can be more firmly bonded to each other by the adhesive layer 601, and the stress concentration generated at the bonding interface between the semiconductor chips 20 can be reduced by appropriately increasing the flexibility of the adhesive layer 601. Can do.

  As a substituent which a 2nd repeating unit has, it is preferable that it is C2-C30, and it is more preferable that it is a C4-C15 linear substituent. When the carbon number is within the above range, the elastic modulus of the photosensitive adhesive composition after curing can be lowered, and the flexibility of the adhesive layer 601 can be increased. Therefore, the adhesive layer 601 can further suppress cracks generated in the semiconductor chip 20 and the adhesive layer 601 due to stress concentration at the bonding interface between the semiconductor chips 20 and peeling between the semiconductor chip 20 and the adhesive layer 601. In addition, it is possible to suppress the occurrence of damage to the semiconductor chip 20 and the adhesive layer 601 due to external impact.

  The second repeating unit may be a cyclic structure, a branched structure, or the like, but is preferably a linear structure. Thereby, the elasticity modulus after hardening of a photosensitive adhesive composition can be lowered | hung more, and the softness | flexibility of the contact bonding layer 601 can be raised more.

  Examples of the linear substituent having 2 to 30 carbon atoms include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, and a group having an alkyl ether structure. It is preferable that it is group which has. Thereby, the photosensitive adhesive composition becomes more excellent in flexibility after curing.

  The group having an alkyl ether structure is particularly preferably a group represented by the following formula (1). Thereby, the softness | flexibility of the contact bonding layer 601 can be improved more.

  In the above formula (1), z is preferably an integer of 1 or more and 10 or less, and more preferably an integer of 2 or more and 6 or less. Thereby, the flexibility of the adhesive layer 601 can be further improved.

  Therefore, the second repeating unit is particularly preferably the following formula (4). (A) In addition to the first repeating unit described above, the alkali-soluble resin has a second repeating unit represented by the following formula (4), so that the solubility of the first repeating unit in an alkaline developer is sufficiently high. It is possible to favorably achieve both the function of being able to increase and the function of making the elastic modulus after curing of the photosensitive adhesive composition by the second repeating unit appropriate.

  In particular, in the above formula (4), z is preferably an integer of 1 or more and 10 or less, and more preferably an integer of 2 or more and 5 or less. Thereby, the elasticity modulus after hardening of a photosensitive adhesive composition can be made more suitable.

  Moreover, when cyclic olefin resin contains a 2nd repeating unit, it is preferable that the content rate of the 2nd repeating unit in cyclic olefin resin is 20-60 mol%, for example, and it is 25-50 mol%. Is more preferable. If the content of the second repeating unit is less than the lower limit, it is difficult to adjust the elastic modulus after curing of the photosensitive adhesive composition to a desired value depending on the type of the second repeating unit. There is a case. Further, when the content of the second repeating unit exceeds the upper limit, depending on the type of the second repeating unit, the characteristics of the cyclic olefin resin other than the second repeating unit are buried. There is a risk that.

  From the above, as the cyclic olefin-based resin, those represented by the following formula (5) are suitable. The photosensitive adhesive composition includes a cyclic olefin-based resin represented by the formula (5), so that the adhesive layer 601 has the necessary mechanical strength and has more appropriate flexibility (stress relaxation). Become. Further, it is possible to obtain an adhesive layer 601 that exhibits particularly excellent solubility in an alkali developer and, in addition, has particularly excellent adhesive strength to the semiconductor chip 20.

  In the above formula (5), l, m, and n are integers of 1 or more. As described above, x is preferably an integer of 0 or more and 10 or less, y is preferably an integer of 0 or more and 10 or less, and z is an integer of 1 or more and 10 or less. preferable.

  In the formula (5), the degree of polymerization of the second repeating unit relative to the degree of polymerization of the first repeating unit (that is, (l + m) / n) is preferably 0.3 to 2.0, 0 More preferably, it is 4-1.5. Thereby, it is possible to obtain a bonding layer 601 that can particularly alleviate the stress concentration generated at the bonding interface between the semiconductor chips 20 and can more firmly bond the semiconductor chips 20 to each other.

  The weight average molecular weight (Mw) of the cyclic olefin resin is preferably 5,000 to 500,000, more preferably 7,000 to 200,000, and 8,000 to 100,000. Is more preferable. Thereby, it is possible to obtain the adhesive layer 601 that is particularly excellent in the adhesive force to the semiconductor chip 20.

  In addition, the weight average molecular weight (Mw) of cyclic olefin resin can be measured using gel permeation chromatography (GPC) using cyclic olefin resin as a standard based on ASTMDS3536-91. .

  The cyclic olefin resin preferably has a glass transition temperature of 100 to 250 ° C. By using the cyclic olefin resin having such a glass transition temperature, the heat resistance of the photosensitive adhesive composition is further increased, and the reliability of the semiconductor device 10 at a high temperature can be further increased.

  In addition, the glass transition temperature of cyclic olefin resin can be calculated | required as temperature which an exothermic reaction produces, when it heats up from normal temperature by the temperature increase rate of 5 degree-C / min, for example by the differential scanning calorimetry.

<(B) Photoacid generator>
(B) A photo-acid generator has a function which produces | generates an acid by the photoreaction at the time of exposure by energy ray irradiation, and increases the solubility with respect to an alkali developing solution. Thereby, in manufacture of a semiconductor device, it is possible to further reduce the occurrence of undissolved residue after development in an exposed portion that is an exposed portion of the photosensitive adhesive composition (coating film 601a). For this reason, the patterning property at the time of development can be improved. In addition, the photosensitive adhesive composition contains (B) a photoacid generator, so that, in the manufacture of semiconductor devices, (C) an epoxy compound (A) which crosslinks an alkali-soluble resin described later by irradiation with energy rays. Can be promoted.

  (B) Specific examples of the photoacid generator include onium salts, halogenated organic compounds, quinonediazide compounds, α, α-bis (sulfonyl) diazomethane compounds, α-carbonyl-α-sulfonyl-diazomethane compounds. , Sulfone compounds, organic acid ester compounds, organic acid amide compounds, organic acid imide compounds, and the like, and one or more of these can be used in combination. Among these, those having a quinonediazide compound are particularly preferable. Examples of the quinonediazide compound include a compound having a 1,2-benzoquinonediazide or a 1,2-naphthoquinonediazide structure. More specifically, it preferably contains 1,2-naphthoquinone-2-diazide-5-sulfonic acid or an ester compound of 1,2-naphthoquinone-2-diazide-4-sulfonic acid and a phenol compound. Since these generate a carboxyl group by a photoreaction at the time of exposure by energy ray irradiation (particularly, radiation irradiation), it is possible to further increase the solubility of an exposed portion in an alkaline developer. For this reason, the photosensitive adhesive composition can exhibit higher solubility in an alkali developer even at a small exposure amount. As a result, the patterning property during development can be further improved.

  (B) Content of a photo-acid generator is although it does not specifically limit, It is preferable that it is 1-50 mass parts with respect to 100 mass parts of (A) alkali-soluble resin, and it is 5-30 mass parts more. preferable. (B) When the content of the photoacid generator is less than the lower limit, depending on the type of the (B) photoacid generator, the exposure and development characteristics of the photosensitive adhesive composition may be deteriorated. . Further, even if the content of (B) the photoacid generator exceeds the above upper limit, no further increase in effect can be expected, and depending on the type of (B) photoacid generator, in the photosensitive adhesive composition In (B), the characteristics of materials other than the photoacid generator may be buried.

<(C) Epoxy compound>
(C) An epoxy compound has a function which bridge | crosslinks (A) alkali-soluble resin (especially cyclic olefin resin).

  (C) The epoxy compound may be either an aromatic epoxy compound containing an aromatic ring in the molecule or an aliphatic epoxy compound containing no aromatic ring in the molecule, but it is an aliphatic epoxy compound. More preferred. Thereby, the crosslinking density of (A) alkali-soluble resin in a photosensitive adhesive composition can be lowered | hung moderately, and the softness | flexibility of the contact bonding layer 601 can be raised moderately.

  The (C) epoxy compound preferably has a branched structure or a linear structure, and more preferably has a branched structure. By including the epoxy compound (C) having a branched structure in the photosensitive adhesive composition, the crosslinking density of the (A) alkali-soluble resin in the photosensitive adhesive composition can be appropriately reduced, and the adhesive layer The flexibility of 601 can be increased moderately. Thereby, the adhesive layer 601 is excellent in stress relaxation property that relaxes the stress concentration generated at the bonding interface between the semiconductor chips 20 while having the necessary mechanical strength.

  The epoxy compound (C) is preferably a compound containing two or more glycidyl groups in the molecule, and more preferably a compound containing three or more and nine or less glycidyl groups in the molecule. . Thereby, the crosslinking density of (A) alkali-soluble resin in a photosensitive adhesive composition can be lowered | hung moderately, and the adhesive layer 601 excellent in stress relaxation property can be obtained, having required mechanical strength. .

  Examples of such (C) epoxy compounds include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether. Sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, EXA-830CRP, EXA-830VLP, EXA-835LV, EXA-850CRP (manufactured by DIC Corporation), YD-8125G, YDF-8170G, ZX-1059, ZX-1542 ( Nippon Steel & Sumikin Chemical Co., Ltd.), YL980, YL7410, YX7700, YED216D (Mitsubishi Chemical Corporation) ), EP-3300S, EP-3950L, EP-4000L, EP-4010L, EP-4088L (Ltd. ADEKA) and the like, it can be used singly or in combination of two or more of them. Among these, trimethylolpropane triglycidyl ether is particularly preferable. Thereby, the crosslinking reaction of the (A) alkali-soluble resin in the photosensitive adhesive composition can be promoted, and the adhesive layer 601 superior in stress relaxation can be obtained more easily and more reliably.

  (C) Although content of an epoxy compound is not specifically limited, It is preferable that it is 1-100 mass parts with respect to 100 mass parts of (A) alkali-soluble resin, and it is more preferable that it is 5-50 mass parts. When the content of the (C) epoxy compound is less than the lower limit, the stress relaxation property of the adhesive layer 601 may be lowered depending on the type of the (C) epoxy compound. On the other hand, if the content of the epoxy compound (C) exceeds the upper limit, the viscosity of the photosensitive adhesive composition may be unnecessarily high.

<(D) Phenol compound having a melting point of 50 to 150 ° C.>
The photosensitive adhesive composition includes, for example, a coating film 601a by including (D) a phenol compound having a melting point of 50 to 150 ° C. (hereinafter, also simply referred to as “(D) phenol compound”). The generation of bubbles between the adhesive layer 601 and the semiconductor chip 20 can be suppressed when the wafer 201 is etched or when the semiconductor chips 20 are bonded to each other via the adhesive layer 601. Further, even when bubbles are generated between the adhesive layer 601 and the semiconductor chip 20, the generated bubbles can be removed. Thus, since it becomes difficult for bubbles to remain at the interface between the adhesive layer 601 and the semiconductor chip 20, the adhesive force of the adhesive layer 601 to the semiconductor chip 20 can be increased, and thus the semiconductor chips 20 are firmly bonded to each other. be able to. Therefore, finally, a highly reliable chip stack 200 can be obtained.

  Furthermore, (D) By using the photosensitive adhesive composition containing a phenol compound, the adhesive layer 601 exhibits a relatively high solubility in an organic solvent. For this reason, for example, even when it is necessary to remove the coating film 601a after forming the coating film 601a obtained by applying the photosensitive adhesive composition to the wafer 201, generation of a residue (residue) is caused. While being suppressed, the coating film 601a can be efficiently dissolved and removed. Thus, the wafer 201 can be used again (reworked) without wasting the wafer 201, and the process yield can be improved.

  The (D) phenol compound has a melting point of 50 to 150 ° C., preferably a melting point of 60 to 130 ° C., more preferably 70 to 120 ° C. Thereby, the effect by including the (D) phenolic compound in the photosensitive adhesive composition mentioned above can be exhibited more notably.

  The (D) phenol compound preferably has a hydroxyl group equivalent of 150 to 250 g / eq, more preferably a hydroxyl group equivalent of 160 to 240 g / eq, and a hydroxyl group equivalent of 180 to 220 g / eq. Further preferred. When the hydroxyl equivalent is within the above range, the solubility of the photosensitive adhesive composition in an alkaline developer can be optimized. On the other hand, if the hydroxyl group equivalent is less than the lower limit, depending on the type and amount of the (D) phenol compound, the water absorption of the photosensitive adhesive composition may increase and the reliability may decrease. . On the other hand, if the hydroxyl equivalent exceeds the upper limit, the solubility in an alkaline developer is remarkably lowered, and the undissolved portion of the photosensitive adhesive composition may be generated after development.

  In addition, the hydroxyl equivalent in (D) phenolic compound can be measured by the method of titrating the solution which mixed (D) phenolic compound in the standard alkaline solution.

(D) phenolic compounds, alkyl chain - preferably contains a substituent having a n _(-CH 2). Thereby, the solubility with respect to the organic solvent of the contact bonding layer 601 can be improved more. For this reason, even when it is necessary to remove the coating film 601a, the coating film 601a can be dissolved and removed more efficiently, so that rework can be performed more easily.

In the alkyl chain (—CH ₂ —) n, the value of n is preferably 1 to 6, and more preferably 2 to 4. Thereby, the solubility with respect to the organic solvent of the contact bonding layer 601 can further be improved.

  Examples of the substituent having such an alkyl chain include a methylene group, an ethylene group, a trimethylene group, a butyl group, and a 2,2-dimethylbutyl group.

  The (D) phenol compound preferably has a structure derived from benzoic acid. Specifically, it preferably has a structure derived from monohydroxybenzoic acid such as benzoic acid, 2-hydroxybenzoic acid and 3-hydroxybenzoic acid, and dihydroxybenzoic acid such as 2,4-hydroxybenzoic acid.

  Specific examples of such (D) phenolic compounds include 4- (1,1-dimethylpropyl) phenol, 4-cyclohexylphenol, 4- (1,1,3,3-tetramethylbutyl). Phenol, 4- (4-hydroxyphenyl) -2-butanone, 4′-hydroxybutyrophenone, 4′-hydroxyvalerophenone, 4′-hydroxyhexanophenone, 3- (4-hydroxyphenyl) propionic acid, 3-hydroxy Methyl benzoate, ethyl 3-hydroxybenzoate, methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, 4-hydroxybenzoate Isobutyl acid, hexyl 4-hydroxybenzoate, 4- Examples thereof include benzyl droxybenzoate, 1,3-bis [2- (4-hydroxyphenyl) -2-propyl] benzene, BisP-DED (manufactured by Honshu Chemical Industry Co., Ltd.), and one or two of these. A combination of the above can be used. Among these, propyl 4-hydroxybenzoate, methyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, and hexyl 4-hydroxybenzoate are preferable. Thereby, the adhesive force of the adhesive layer 601 to the semiconductor chip 20 can be particularly increased, and the solubility of the adhesive layer 601 in the organic solvent can be further improved.

  (D) It is preferable that content of a phenol compound is 0.5-30 mass parts with respect to 100 mass parts of (A) alkali-soluble resin, and it is more preferable that it is 1-20 mass parts. If the content of the (D) phenol compound is less than the lower limit, the solubility of the photosensitive adhesive composition in the organic solvent may be reduced depending on the type of the (D) phenol compound. (D) Even if the content of the phenol compound exceeds the above upper limit, no further increase in effect can be expected. (D) Depending on the type of the phenol compound, (D) the phenol compound in the photosensitive adhesive composition There is a possibility that the characteristics of other materials may be buried.

  Moreover, it is preferable that a photosensitive adhesive composition contains 2 or more types of the above (D) phenolic compounds. Specifically, it is preferable to include two or more types of (D) phenol compounds having different melting points, and more preferably to include two types. Thereby, the adhesiveness of the photosensitive adhesive composition (adhesive layer 601), stress relaxation property, and the solubility with respect to the organic solvent can be improved more.

  In addition, even when it contains 2 or more types of (D) phenolic compounds, it is preferable that content of (D) phenolic compounds exists in the range mentioned above.

  The photosensitive adhesive composition contains (A) an alkali-soluble resin, (B) a photoacid generator, (C) an epoxy compound, and (D) a phenol compound as described above, thereby manufacturing a semiconductor device. In, for example, when the wafer 201 provided with the coating film 601a is etched or when the semiconductor chips 20 are pressure-bonded via the adhesive layer 601, bubbles are hardly left at the interface between the adhesive layer 601 and the semiconductor chip 20. Become. For this reason, the semiconductor chips 20 can be firmly bonded to each other by the adhesive layer 601, and thus a highly reliable chip stack 200 can be obtained. Moreover, although the adhesive layer 601 has a single-layer structure, it has stress relaxation properties in addition to sufficient adhesiveness. For this reason, it is not necessary to provide two layers of the layer excellent in adhesiveness and the layer excellent in stress relaxation between the semiconductor chips 20, Therefore, the whole thickness of the chip laminated body 200 is remarkably thick. Can be avoided. As a result, it is possible to obtain a highly reliable semiconductor device 10 having a low profile and excellent adhesion and stress relaxation properties. Such a semiconductor device 10 has a very small internal volume, such as a mobile device, and is particularly useful in an electronic device that is used while being carried. That is, it is useful in that it contributes to the reduction in size, thickness, and weight of the electronic device and that the function of the semiconductor device 10 is hardly impaired even when the electronic device is dropped or swung.

  The cured product of the photosensitive adhesive composition containing (A) an alkali-soluble resin, (B) a photoacid generator, (C) an epoxy compound, and (D) a phenol compound is soluble in an organic solvent. It is also excellent in that it is easy to perform rework.

  Moreover, it is preferable that such a photosensitive adhesive composition further includes a phenol compound having a melting point of 100 to 150 ° C. and a phenol compound having a melting point of 150 to 250 ° C. By including these, it is possible to obtain an adhesive layer 601 that is particularly excellent in adhesiveness, stress relaxation, and solubility in organic solvents.

  In addition, the photosensitive adhesive composition may include (D) a phenol compound, a phenol compound having a melting point of 100 to 150 ° C., and a phenol compound other than the phenol compound having a melting point of 150 to 250 ° C. Further, a leveling agent, a flame retardant, a plasticizer, a curing accelerator, an antioxidant, an adhesion assistant, and the like may be further included.

  Examples of the antioxidant include a phenolic antioxidant, an amine antioxidant, a phosphorus antioxidant, and a thioether antioxidant, and one or a combination of two or more of these may be used. Among these, it is preferable to use a combination of a phenolic antioxidant and an amine antioxidant.

  By including such an antioxidant, it is possible to suppress oxidation during curing of the photosensitive adhesive composition and oxidation of the photosensitive adhesive composition (coating film 601a) in the subsequent processes.

  Examples of phenolic antioxidants include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis {2- [3- (3-t -Butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} 2,4,8,10-tetraoxaspiro [5,5] undecane, octadecyl-3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionate, 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl -2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 2,6-di-t-butyl-4-methylphenol, 2,6-di- -Butyl-4-ethylphenol, 2,6-diphenyl-4-octadecyloxyphenol, 2,6-bis [(2-hydroxy-5-methylphenyl) methyl] -4-methylphenol, stearyl (3,5 -Di-t-butyl-4-hydroxyphenyl) propionate, distearyl (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate, thiodiethylene glycol bis [(3,5-di-t-butyl-4 -Hydroxyphenyl) propionate], 4,4'-thiobis (6-tert-butyl-m-cresol), 2-octylthio-4,6-di (3,5-di-tert-butyl-4-hydroxyphenoxy) -S-triazine, 2,2'-methylenebis (4-methyl-6-tert-butyl-6-butylphenol), 2,2'-methylene (4-ethyl-6-tert-butylphenol), bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, 4,4′-butylidenebis (6-t- Butyl-m-cresol), 2,2'-ethylidenebis (4,6-di-t-butylphenol), 2,2'-ethylidenebis (4-s-butyl-6-t-butylphenol), 1,1 , 3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, bis [2-t-butyl-4-methyl-6- (2-hydroxy-3-t-butyl-5-methyl) Benzyl) phenyl] terephthalate, 1.3.5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-t- Butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,3,5-tris [(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, tetrakis [ Methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 2-tert-butyl-4-methyl-6- (2-acryloyloxy-3-tert-butyl-5- Methylbenzyl) phenol, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4-8,10-tetraoxaspiro [5,5] undecane-bis [β- (3-t- Butyl-4-hydroxy-5-methylphenyl) propionate], triethylene glycol bis [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) Propionate], 1,1'-bis (4-hydroxyphenyl) cyclohexane, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-) Butylphenol), 2,2′-methylenebis (6- (1-methylcyclohexyl) -4-methylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis (2 -(3-t-butyl-4-hydroxy-5-methylphenylpropionyloxy) 1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5,5) undecane, 4,4'- Thiobis (3-methyl-6-tert-butylphenol), 4,4′-bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 4,4 ′ -Thiobis (6-tert-butyl-2-methylphenol), 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2-tert-butyl-6- (3-tert-butyl) -2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-dimethyl-6- (1-methylcyclohexyl, styrenated phenol, 2,4-bis ((octylthio) methyl) -5 And methylphenol. Of these, phenolic antioxidants such as 2,6-bis [(2-hydroxy-5-methylphenyl) methyl] -4-methylphenol are preferred.

  Examples of amine-based antioxidants include N, N′-di-sec-butyl-p-phenylenediamine, 4,4′-dimethoxydiphenylamine, 4-isopoloxydiphenylamine, N-isopropyl-N′-phenyl-p-phenylene. Examples include diamine, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, 4,4′-di (α, α-dimethylbenzyl) diphenylamine, and among these, 4,4 Diphenylamine compounds such as' -dimethoxydiphenylamine, 4-isopoloxydiphenylamine, and 4,4'-di (α, α-dimethylbenzyl) diphenylamine are preferred.

  Phosphorus antioxidants include bis- (2,6-di-t-butyl-4-methylphenyl) pentapentaerythritol diphosphite, tris (2,4-di-t-butylphenyl phosphite), tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, bis- (2 , 6-Dicumylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, tris (mixed mono and di-nonylphenyl phosphite), bis ( 2,4-di-t-butylphenyl) pentapentaerythritol-di-phosphite, bis (2,6-di-t-butyl) 4-methoxycarbonyl-ethyl - phenyl) pentaerythritol diphosphite, bis (2,6-di -t- butyl-4-octadecyloxycarbonyl ethyl - phenyl) pentaerythritol diphosphite and the like. Of these, phosphites and phosphates are preferred.

  Thioether antioxidants include dilauryl 3,3′-thiodipropionate, bis (2-methyl-4- (3-n-dodecyl) thiopropionyloxy) -5-tert-butylphenyl) sulfide, distearyl -3,3'-thiodipropionate, pentaerythritol-tetrakis (3-lauryl) thiopropionate, and the like.

  When a photosensitive adhesive composition contains antioxidant, it is preferable that content of antioxidant is 0.1-50 mass parts with respect to 100 mass parts of (A) alkali-soluble resin, 0.5. More preferably, it is -30 mass parts.

  Examples of adhesion assistants include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 5 , 6-epoxyhexyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri Ethoxysilane, 3-acryloxypropyltrimethoxysilane, bis [3- (triethoxysilyl) propyl] tetrasulfide, bis [3- (triethoxysilyl) propyl] disulfide, 3-isocyanatopropyl Riethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, benzoyloxypropyltrimethoxysilane, benzoyloxypropyltriethoxysilane, 1,6-bis (trimethoxysilyl) hexane, norbornenyltrimethoxysilane, nor Bornenyltriethoxysilane, 3- (triethoxysilyl) propylsuccinic anhydride, 6-azidosulfonylhexyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltriethoxysilane, tris (3-trimethoxysilylpropyl) isocyanurate, [2- (3-cyclohexenyl) ethyl] trimethoxysilane, [2- (3-cyclohexenyl) ethyl] triethoxy Silane, (3-cyclopentadienylpropyl) triethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, n-octyltri Ethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, bis (triethoxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ethane, bis (tri Methoxysilyl) hexane, bis (triethoxysilyl) hexane, bis (trimethoxysilyl) octane, bis (triethoxysilyl) octane, bis (trimethoxysilyl) benzene, bis [(3-methyldimethoxy Silyl) propyl] polypropylene oxide, polymethacrylic acid trimethoxysilyl ester, polymethacrylic acid triethoxysilyl ester, trifluoropropyltrimethoxysilane, 1,3-dimethyltetramethoxydisiloxane, and the like. Is not limited to these. These may be used alone or in admixture of two or more. By including such an adhesion assistant, the adhesion force (adhesion force) of the adhesive layer 601 obtained from the photosensitive adhesive composition to the semiconductor chip 20 can be further increased.

  When the photosensitive adhesive composition contains an adhesion assistant, the content of the adhesion assistant is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the (A) alkali-soluble resin, and 0.2 More preferably, it is -20 mass parts.

Next, specific examples of the present invention will be described.
Example 1
[1] (A) Synthesis of Alkali-Soluble Resin (Cyclic Olefin Resin A-1) A plurality of glass devices were prepared, and these were dried at 60 ° C. under 0.1 Torr for 18 hours. Thereafter, all glass equipment was installed in the glow box.

  Next, toluene (992 g), dimethoxyethane (116 g), 1,1-bistrifluoromethyl-2- (bicyclo [2.2.1] hept-2-ene-5 was added to one glass device (glass device X). -Yl) ethyl alcohol (hereinafter, HFANB) (148 g, 0.54 mol), ethyl 3- (bicyclo [2.2.1] hept-2-en-2-yl) propanate (hereinafter, EPEsNB) (20.7 g) 0.107 mol), 5-((2- (2-methoxyethoxy) ethoxy) methyl) bicyclo [2.2.1] hept-2-ene (hereinafter, NBTON) (61.9 g, 0.274 mol). Prepared. Then, purging was performed by flowing nitrogen for 30 minutes while heating these charged monomers at 45 ° C.

  In another glass device (glass device Y), EPEsNB (14.2 g, 0.073 mol) and NBTON (46.7 g, 0.159 mol) were mixed and purged with nitrogen. After the nitrogen purge was completed, bis (toluene) bis (perfluorophenyl) nickel (5.82 g, 0.012 mol) dissolved in 60.5 ml of toluene was put into the glass apparatus Y. At the same time, the monomer mixed in the glass apparatus X described above was added into the glass apparatus Y over 3 hours at such a rate as to keep it at a constant level for polymerization, thereby obtaining a reaction solution.

  Next, the reaction solution was dissolved in about 1 L of methanol / THF (= 4 mol / 5 mol) solution to remove unreacted monomers, and then sodium hydroxide / sodium acetate (= 4) at 60 ° C. for 4 hours. The ester was hydrolyzed with sodium hydroxide solution (.8 mol / 1 mol). Thereafter, methanol (405 g), THF (87 g), acetic acid (67 g), formic acid (67 g) and deionized water (21 g) were added, and the mixture was stirred at 50 ° C. for 15 minutes. When the stirring is stopped, the solution is separated into an aqueous layer and an organic layer. The upper aqueous layer is removed, and the organic layer is washed with a methanol / deionized water (= 390 g / 2376 g) solution three times at 60 ° C. for 15 minutes. did. And the obtained polymer was diluted in the solvent and solvent substitution was carried out. Thus, the polymer (cyclic olefin resin A-1) shown by Formula (7) was obtained.

  The yield of cyclic olefin resin A-1 was 93.1%. The weight average molecular weight (Mw) of the cyclic olefin resin A-1 was 85,900. The molecular weight dispersion (PD) of the cyclic olefin resin A-1 was 2.52.

The composition of the cyclic olefin-based resin A-1 is as follows: ¹ H-NMR, HFANB is 45.0 mol%, 2- (bicyclo [2.2.1] hept-2-en-5-yl) propionic acid (Hereinafter, EPENB) was 15.0 mol%, and NBTON was 40.0 mol%.

（式（７）中、ｌ：ｍ：ｎ＝４５：１５：４０である。）

(In formula (7), l: m: n = 45: 15: 40)

[2] Production of photosensitive adhesive composition (A) Cyclic olefin resin A-1 (22.0 parts by mass) as an alkali-soluble resin obtained in [1], and (B) Photoacid generation Photoacid generator B-1 (4.0 parts by mass) as an agent, (C) Epoxy compound C-1 (5.0 parts by mass) as an epoxy compound, and (D) Phenol compound D as a phenol compound -1 (3.0 parts by mass), antioxidant E-1 (2.0 parts by mass), antioxidant E-2 (3.0 parts by mass), and propylene glycol methyl as a solvent (solvent) Ether acetate (61.0 parts by mass) was mixed to obtain a uniform photosensitive adhesive composition.
The materials used in the photosensitive adhesive composition of Example 1 are shown below.

<Photoacid generator B-1>
A compound represented by the following formula (8) was prepared as the photoacid generator B-1.

<Epoxy compound C-1>
As the epoxy compound C-1, a compound represented by the following formula (9) was prepared.

<Phenol compound D-1>
As phenol compound D-1, the compound 4-hydroxybenzoate butyl represented by following formula (10) was prepared.

  The melting point of the phenol compound D-1 was 70 ° C. The weight average molecular weight (Mw) of the phenol compound D-1 was 194. The hydroxyl equivalent of the phenol compound D-1 was 194 g / eq.

<Antioxidant E-1>
A compound represented by the following formula (11) (4,4′-di (α, α-dimethylbenzyl) diphenylamine) was prepared as the antioxidant E-1.

<Antioxidant E-2>
As the antioxidant E-2, a compound represented by the following formula (12) (2,6-bis [(2-hydroxy-5-methylphenyl) methyl] -4-methylphenol) was prepared.

(Examples 2 to 7)
A photosensitive adhesive composition was obtained in the same manner as in Example 1 except that the materials constituting the photosensitive adhesive composition were changed to those shown in Table 1 and the respective contents were changed to the contents shown in Table 1. It was.

(Examples 8 to 14)
A photosensitive adhesive composition was obtained in the same manner as in Example 1 except that the materials constituting the photosensitive adhesive composition were changed to those shown in Table 2 and the respective contents were changed to those shown in Table 2. It was.

(Comparative Examples 1-10)
A photosensitive adhesive composition was obtained in the same manner as in Example 1 except that the materials constituting the photosensitive adhesive composition were changed to those shown in Table 3 and the respective contents were changed to those shown in Table 3. It was.
In addition, the material used with the photosensitive adhesive composition of each Example and each comparative example is shown below.

<Cyclic olefin resin A-2>
As cyclic olefin resin A-2 ((A) alkali-soluble resin), a compound represented by the following formula (13) was prepared.

（式（１３）中、ｌ：ｍ：ｎ＝２５：１５：６０である。）

(In formula (13), l: m: n = 25: 15: 60)

<Cyclic olefin resin A-3>
As cyclic olefin resin A-3 ((A) alkali-soluble resin), a compound represented by the following formula (14) was prepared.

（式（１４）中、ｌ：ｍ：ｎ＝２５：３５：４０である。）

(In formula (14), l: m: n = 25: 35: 40)

<Phenol compound D-2>
A compound (hexyl 4-hydroxybenzoate) represented by the following formula (15) was prepared as the phenol compound D-2 ((D) phenol compound).

  The melting point of the phenol compound D-2 was 53 ° C. The weight average molecular weight (Mw) of the phenol compound D-2 was 222. The hydroxyl equivalent of the phenol compound D-2 was 222 g / eq.

<Phenol compound D-3>
As phenol compound D-3 ((D) phenol compound), a compound (methyl 4-hydroxybenzoate) represented by the following formula (16) was prepared.

  The melting point of the phenol compound D-3 was 127 ° C. The weight average molecular weight (Mw) of the phenol compound D-3 was 152. The hydroxyl equivalent of the phenol compound D-3 was 152 g / eq.

[3] Preparation of test piece for evaluation First, the photosensitive adhesive composition was applied on a semiconductor chip made of silicon, and prebaked at 120 ° C. for 5 minutes. This obtained the coating film.

  Subsequently, the obtained coating film was heat-treated at the heating temperature and heating time described in Tables 1 to 3.

Next, an etching treatment and an ashing treatment were sequentially performed on the heat-treated coating film. The etching process uses a mixed gas of fluorine compound gas (CF ₄ ), argon gas (Ar) and oxygen gas (O ₂ ), the output is 2500 W, the time is 6 minutes, and the CF ₄ flow rate / Ar flow rate / O ₂ flow rate is The ashing process was performed using O ₂ gas, the output was 600 W, the time was 12 minutes, and the O ₂ flow rate was 200 sccm.

  Next, another semiconductor chip was stacked through the coating film, and was pressed with a load of 10 N for 5 seconds while heating at a temperature of 150 ° C.

  As described above, an evaluation test piece in which two semiconductor chips were bonded via an adhesive layer was produced.

[4] Evaluation of photosensitive adhesive composition or test piece for evaluation [4.1] Evaluation of substrate adhesion (Scotch tape test)
First, the photosensitive adhesive composition was applied onto a silicon wafer, pre-baked at 120 ° C. for 5 minutes, and then heat-treated at the heating temperature and heating time shown in Tables 1 to 3.

Next, the heat-treated coating film was cut using a cutter at intervals of 1 mm in length and width. And the cross cut tape test (JIS K5400) was done with respect to the cut-in coating film using the scotch tape.
Next, the adhesion between the coating film and the silicon wafer was evaluated based on the following evaluation criteria.

<Evaluation criteria>
◎: Coating film peeling rate of less than 5% ○: Coating film peeling rate of 5% or more and less than 10% Δ: Coating film peeling rate of 10% or more and less than 30% ×: Coating film peeling rate Tables 1 to 3 show the evaluation results of 30% or more.

[4.2] Evaluation of reworkability First, the photosensitive adhesive composition used in each example and each comparative example was applied on a silicon wafer, and prebaked at 120 ° C. for 5 minutes. This obtained the coating film.

  Subsequently, the obtained coating film was heat-treated at the heating temperature and heating time described in Tables 1 to 3.

  Next, the heat-treated coating film was immersed in propylene glycol-1-monomethyl ether-2-acetate and allowed to stand for 20 hours.

  Subsequently, the semiconductor chip was taken out from propylene glycol-1-monomethyl ether-2-acetate, and the presence or absence of a coating film residue was visually observed, and based on this, the reworkability was evaluated. The reworkability was evaluated based on the following evaluation criteria.

<Evaluation criteria>
A: No coating film residue is observed.
◯: A slight coating residue is observed.
Δ: Many coating film residues are observed.
X: The coating film is hardly removed.
The above evaluation results are shown in Tables 1-3.

[4.3] Evaluation of Adhesiveness to Semiconductor Chip (Chip Adhesiveness) First, with respect to the test piece for evaluation obtained in [3], a universal bond tester Dage4000 (manufactured by Daisy Japan Co., Ltd.) was used. The semiconductor chip was pushed in the horizontal direction with a shear tool from the side (side surface) of the substrate, and the die shear strength per chip when the joint surface between the chips was broken was measured. The chip size was 4 mm × 4 mm.
And the measured die shear strength was evaluated based on the following evaluation criteria.

<Evaluation criteria>
A: Die shear strength (chip adhesion) is very high.
○: Die shear strength (chip adhesion) is high.
Δ: Die shear strength (chip adhesion) is low.
X: Die shear strength (chip adhesion) is very low.
The above evaluation results are shown in Tables 1-3.

[4.4] Evaluation of Photosensitivity of Photosensitive Adhesive Composition First, the photosensitive adhesive composition used in Examples 1 to 7 was applied on a silicon semiconductor chip and pre-baked at 120 ° C. for 5 minutes. Went. Thereby, a coating film having a thickness of 10 μm was obtained.

Next, the obtained coating film was subjected to an exposure treatment through a line and space pattern mask having a width of 100 μm. In addition, this exposure process was performed by irradiating the light whose wavelength is 365 nm and light intensity is 5 mW / cm < ² > in the air, changing time for every coating film.

Next, development processing was performed on the coating film that had been subjected to exposure processing. The minimum exposure amount (unit: mJ / cm) when the remaining film ratio of the unexposed area defined as follows is 90% or more and the remaining film ratio of the exposed area is 0%. ² ) was obtained.
Residual film ratio = 100 × film thickness after development of unexposed area / film thickness after pre-baking

Table 1 shows the obtained exposure amounts.
In addition, the same exposure treatment and development treatment as described above were applied to the coating films obtained from the photosensitive adhesive compositions used in Examples 8 to 14 and each Comparative Example. Then, the minimum exposure amount when the remaining film ratio of the unexposed portion is 90% or more and the remaining film ratio of the exposed portion is 0% was obtained, and this was evaluated based on the following evaluation criteria. .

<Evaluation criteria>
A: The exposure amount is less than 300 mJ / cm ² .
(Triangle | delta): The exposure amount is 300 mJ / cm < ² > or more and less than 700 mJ / cm < ² >.
X: The exposure amount is 700 mJ / cm ² or more.
The above evaluation results are shown in Tables 2 and 3.

[4.5] Evaluation of change in elastic modulus before and after heating step First, the photosensitive adhesive compositions used in Examples 8 to 14 and each comparative example were applied on a silicon semiconductor chip, and 120 ° C. Pre-baking was performed for 5 minutes.

Next, the obtained coating film was subjected to an exposure treatment through a line and space pattern mask having a width of 100 μm. In addition, this exposure process was performed by irradiating the light whose wavelength is 365 nm and light intensity is 5 mW / cm < ² > in the air, changing time for every coating film.

Next, development processing was performed on the coating film that had been subjected to exposure processing.
Next, the coating film subjected to the development treatment was subjected to a heating treatment at the heating temperature and the heating time described in Tables 2 and 3.

Next, an etching treatment and an ashing treatment were sequentially performed on the heat-treated coating film. The etching process uses a mixed gas of fluorine compound gas (CF ₄ ), argon gas (Ar) and oxygen gas (O ₂ ), the output is 2500 W, the time is 6 minutes, and the CF ₄ flow rate / Ar flow rate / O ₂ flow rate is The ashing process was performed using O ₂ gas, the output was 600 W, the time was 12 minutes, and the O ₂ flow rate was 200 sccm.

And X / Y was calculated | required by making elastic modulus (25 degreeC) before this etching process etc. into X [GPa], and making the elastic modulus (25 degreeC) after etching processes etc. into Y [GPa].
The obtained X / Y is shown in Tables 2 and 3.

  As is apparent from Tables 1 to 3, the coating film used in each example was found to have sufficient adhesion between the underlying silicon wafer and the adhesive layer as a result of the predetermined heat treatment. Moreover, it has sufficient solubility with respect to the organic solvent, and so-called reworkability was good. Furthermore, it is recognized that the test piece for evaluation of each example has sufficient adhesion to the semiconductor chip while suppressing bubbles remaining at the interface with the semiconductor chip as a result of the predetermined heat treatment. It was.

  From the above, according to the present invention, by optimizing the heating conditions in the heating process, the adhesive layer patterned with high accuracy while suppressing the remaining of bubbles between the semiconductor chip and the adhesive layer. It was found that the semiconductor chips can be bonded to each other via the. As a result, it is possible to realize a semiconductor device having a highly reliable chip stack with high adhesion between semiconductor chips.

4 Mask 10 Semiconductor device 20 Semiconductor chip 21 Piece 22 Piece 30 Package substrate 31 Core substrate 32 Insulating layer 33 Solder resist layer 34 Wiring 35 Conductive via 50 Mold part 70 Bonding wire 80 Solder ball 90 Back grind film 100 Dicing die attach Film 100a Dicing film 100b Die attach film 101 Adhesive layer 110 Dicing blade 120 Bonding device 121 Collet 200 Chip laminate 201 Wafer 601 Adhesive layer 601a Paint film 601b Opening

Claims (8)

A method of manufacturing a semiconductor device including a stacked semiconductor element formed by stacking a first semiconductor element and a second semiconductor element,
An application step of applying a liquid containing a photosensitive adhesive composition to one surface side of the first semiconductor element;
An exposure step of performing an exposure process on the coating film obtained by the coating step;
A development step of performing a development treatment on the coating film subjected to the exposure treatment;
A heating step of heating the coating film subjected to the development treatment;
A processing step of performing an etching process on the first semiconductor element provided with the heated coating film;
A mounting step of stacking the first semiconductor element and the second semiconductor element through the coating film to obtain the stacked semiconductor element;
Have
The method of manufacturing a semiconductor device, wherein heating conditions in the heating step are a temperature of 80 to 170 ° C. and a time of 35 to 120 minutes.   The method for manufacturing a semiconductor device according to claim 1, further comprising a back grinding process for grinding the other surface side of the first semiconductor element. In the application step, the liquid is applied to one surface side of a semiconductor substrate including the first semiconductor element and the second semiconductor element,
In the back grinding process, the other surface side of the semiconductor substrate is ground,
A dicing process is provided before or after the back grinding process, and the semiconductor substrate is diced to separate the semiconductor substrate, and the first semiconductor element and the second semiconductor element are separated from the semiconductor substrate. Furthermore, the manufacturing method of the semiconductor device of Claim 2 which has. The photosensitive adhesive composition is
(A) an alkali-soluble resin;
(B) a photoacid generator;
(C) an epoxy compound;
(D) a phenolic compound;
The method for manufacturing a semiconductor device according to claim 1, comprising:   The method of manufacturing a semiconductor device according to claim 4, wherein the (A) alkali-soluble resin is a cyclic olefin-based resin including a repeating unit having an acidic group.   The method for manufacturing a semiconductor device according to claim 5, wherein the cyclic olefin-based resin is a norbornene-based resin.   The method for manufacturing a semiconductor device according to claim 4, wherein the (C) epoxy compound includes two or more glycidyl groups in a molecule.   The elastic modulus at 25 ° C. of the coating film after the heating step and before the treatment step is X [GPa], and the elastic modulus at 25 ° C. of the coating film after the treatment step is Y [GPa]. The method for manufacturing a semiconductor device according to claim 7, wherein the relationship of 0.7 ≦ X / Y ≦ 1.5 is satisfied.

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