Patent Application
20240043722
The present disclosure relates to a film-shaped adhesive, a dicing-die bonding integrated film, a semiconductor device, and a method for manufacturing the semiconductor device.
Conventionally, a semiconductor device is manufactured through the following steps. First, a semiconductor wafer is stuck to an adhesive sheet for dicing, and while in that state, the semiconductor wafer is singulated into semiconductor chips (dicing step). Subsequently, a pickup step, a pressure-bonding step, a die bonding step, and the like are carried out. In Patent Literature 1, an adhesive film (dicing-die bonding integrated film) combining a function of fixing a semiconductor wafer in a dicing step and a function of adhering semiconductor chips to a substrate in a die bonding step, is disclosed. An adhesive piece-attached semiconductor chip can be obtained by singulating a semiconductor wafer and a bonding adhesive layer in the dicing step.
In recent years, devices called power semiconductor devices that perform control of electric power and the like have been popularized. Power semiconductor devices are likely to generate heat due to the electric current supplied thereto and are required to have excellent heat dissipation properties. In Patent Literature 2, a film-shaped adhesive having higher heat dissipation properties after curing compared with the heat dissipation properties before curing is disclosed.
Meanwhile, with regard to the manufacture of a semiconductor device, a film-shaped adhesive is required to have level difference embedding properties of following fine level differences (surface unevenness) on a substrate and embedding those level differences. However, since conventional film-shaped adhesives contain many metal particles in order to improve heat dissipation properties, the level difference embedding properties are not sufficient, and there is still room for improvement.
Thus, it is an object of the present disclosure to provide a film-shaped adhesive that enables manufacture of a semiconductor device having excellent heat dissipation properties and has excellent level difference embedding properties.
In order that the inventors of the present disclosure can solve the above-described problems, the inventors paid attention to the correlation between various parameters and the level difference embedding properties under the conditions of containing metal particles and conducted an investigation, and the inventors found that the parameters of shear viscosity and loss modulus at 110° C. are highly correlated with the quality of the level difference embedding properties, thus completing the invention of the present disclosure.
An aspect of the present disclosure relates to a film-shaped adhesive.
An embodiment of the film-shaped adhesive contains metal particles and has a shear viscosity at 110° C. of 30000 Pa·s or less. The film-shaped adhesive may have a loss modulus at 110° C. of 200 kPa or less.
Another embodiment of the film-shaped adhesive contains metal particles and has a loss modulus at 110° C. of 200 kPa or less.
These film-shaped adhesives may further contain a thermosetting resin, a curing agent, and an elastomer. In this case, a content of the metal particles may be 70.0% by mass or more or 20.0% by volume or more, based on a total amount of the metal particles, the thermosetting resin, the curing agent, and the elastomer.
Another embodiment of the film-shaped adhesive contains metal particles, a thermosetting resin, a curing agent, and an elastomer. A content of the metal particles is 70.0% by mass or more based on the total amount of the metal particles, the thermosetting resin, the curing agent, and the elastomer, and a total content of the thermosetting resin and the curing agent is 13.0% by mass or more.
The metal particles may be conductive particles and may be silver particles.
According to the film-shaped adhesive of an aspect of the present disclosure, a semiconductor device having excellent heat dissipation properties can be manufactured, and at the same time, the film-shaped adhesive has excellent level difference embedding properties.
Another aspect of the present disclosure relates to a dicing-die bonding integrated film. This dicing-die bonding integrated film includes a base material layer, a pressure-sensitive adhesive layer, and a bonding adhesive layer formed from the above-described film-shaped adhesive, in this order.
Another aspect of the present disclosure relates to a semiconductor device. This semiconductor device includes: a semiconductor chip; a support member having the semiconductor chip mounted thereon; and a bonding adhesive member provided between the semiconductor chip and the support member and adhering the semiconductor chip and the support member. The bonding adhesive member is a cured product of the above-described film-shaped adhesive.
Another aspect of the present disclosure relates to a method for manufacturing a semiconductor device. This method for manufacturing a semiconductor device includes: sticking a semiconductor wafer to a bonding adhesive layer of the above-described dicing-die bonding integrated film; producing a plurality of singulated adhesive piece-attached semiconductor chips by dicing the semiconductor wafer with the bonding adhesive layer stuck thereto; and adhering the adhesive piece-attached semiconductor chips to a support member, with the adhesive piece interposed therebetween.
According to the present disclosure, there is provided a film-shaped adhesive that enables manufacture of a semiconductor device having excellent heat dissipation properties and also has excellent level difference embedding properties. Furthermore, according to the present disclosure, there is provided a dicing-die bonding integrated film that uses such a film-shaped adhesive. In addition, according to the present disclosure, there are provided a semiconductor device that uses such a film-shaped adhesive or such a dicing-die bonding integrated film, and a method for manufacturing the semiconductor device.
Hereinafter, embodiments of the present disclosure will be described with appropriate reference to the drawings. However, the present disclosure is not intended to be limited to the following embodiments. In the following embodiments, the constituent elements thereof (also including steps and the like) are not essential unless particularly stated otherwise. The sizes of constituent elements in each drawing are conceptual, and the relative relationship between the sizes of the constituent elements is not limited to that shown in each drawing.
In the present specification, a numerical value range indicated by using the term “to” represents a range including the numerical values described before and after the term “to” as the minimum value and the maximum value, respectively. With regard to a numerical value range described stepwise in the present specification, the upper limit value or lower limit value of a numerical value range of a certain stage may be replaced with the upper limit value or the lower limit value of a numerical value range of another stage. Furthermore, with regard to a numerical value range described in the present specification, the upper limit value or the lower limit value of the numerical value range may be replaced with a value shown in Examples. Furthermore, separately described upper limit values and lower limit values can be arbitrarily combined. Furthermore, in the present specification, the term “(meth)acrylate” means at least one of acrylate and methacrylate corresponding thereto. The same also applies to other similar expressions such as “(meth)acryloyl”. Furthermore, the term “(poly)” means both a case with the prefix “poly” and a case without the prefix “poly”. Furthermore, the expression “A or B” may include any one of A and B or may include both of them. Furthermore, unless particularly stated otherwise, the materials mentioned below as examples may be used singly, or two or more kinds thereof may be used in combination. Regarding the content of each component in a composition, in a case where a plurality of substances corresponding to each component are present in a composition, unless particularly stated otherwise, the content means the total amount of the plurality of substances present in the composition.
The support film 20 is not particularly limited, and examples thereof include films of polytetrafluoroethylene, polyethylene, polypropylene, polymethylpentene, polyethylene terephthalate, polyimide, and the like. The support film may be subjected to a mold release treatment. The thickness of the support film 20 may be, for example, 10 to 200 μm or 20 to 170 μm.
An embodiment of the film-shaped adhesive 10A contains metal particles (may be referred to as “component (A)”) and satisfies either the following condition (i) or the following condition (ii). At this time, this film-shaped adhesive may satisfy both the condition (i) and the condition (ii).
According to an investigation of the inventors of the present disclosure, it was found that in a case where a film-shaped adhesive contains component (A), the parameters of shear viscosity and loss modulus at 110° C. of the film-shaped adhesive are highly correlated with the quality of the level difference embedding properties. Therefore, a film-shaped adhesive that satisfies the above-described conditions enables manufacture of a semiconductor device having excellent heat dissipation properties and has excellent level difference embedding properties.
The shear viscosity at 110° C. of the film-shaped adhesive is 30000 Pa·s or less and may be 28000 Pa·s or less, 26000 Pa·s or less, 25000 Pa·s or less, 24000 Pa·s or less, 22000 Pa·s or less, 20000 Pa·s or less, 18000 Pa·s or less, or 15000 Pa·s or less. The lower limit of the shear viscosity at 110° C. of the film-shaped adhesive is not particularly limited; however, for example, the lower limit may be 3000 Pa·s or higher, 5000 Pa·s or higher, 6000 Pa·s or higher, or 7000 Pa·s or higher.
The shear viscosity at 110° C. can be measured by, for example, the following method. First, a film-shaped adhesive having a thickness of 25 μm is cut into a predetermined size to prepare twelve sheets of film pieces. Next, the twelve sheets of the film pieces are laminated on a hot plate at by using a rubber roll, and a laminated body having a thickness of 300 μm is prepared. Next, the laminated body is punched out using a punch of ϕ9 mm to produce a sample, and for the produced sample, the shear viscosity is measured by using a rotary viscoelasticity measuring apparatus (manufactured by TA Instruments Japan Inc., trade name: ARES-RDA) under the following measurement conditions. At this time, the measured value of shear viscosity at 110° C. is the shear viscosity at 110° C. Incidentally, when setting a gap, the gap is regulated such that the load exerted on the sample is 10 to 15 g.
(Measurement Conditions)
The loss modulus at 110° C. of the film-shaped adhesive is 200 kPa or less and may be 190 kPa or less, 180 kPa or less, 170 kPa or less, 165 kPa or less, 160 kPa or less, 155 kPa or less, 150 kPa or less, 145 kPa or less, 140 kPa or less, 135 kPa or less, 130 kPa or less, 125 kPa or less, or 120 kPa or less. The lower limit of the loss modulus at 110° C. of the film-shaped adhesive is not particularly limited; however, the low limit may be, for example, 10 kPa or more, 20 kPa or more, 30 kPa or more, 40 kPa or more, or 50 kPa or more.
The loss modulus at 110° C. can be obtained by using a rotary viscoelasticity measuring apparatus, in the same manner as in the above-described method of measuring the shear viscosity at 110° C.
The shear viscosity and loss modulus at 110° C. can be reduced by, for example, methods of reducing the content of the component (A) (increasing the contents of components other than the component (A)); increasing the proportion of the total amount of a thermosetting resin and a curing agent, with respect to the total amount of the component (A), the thermosetting resin that will be described below, the curing agent that will be described below, and an elastomer that will be described below; applying a thermosetting resin or curing agent having a softening point of 90° C. or lower; and applying an elastomer having a small molecular weight.
The film-shaped adhesive 10A may further contain a thermosetting resin (hereinafter, may be referred to as “component (B)”), a curing agent (hereinafter, may be referred to as “component (C)”), and an elastomer (hereinafter, may be referred to as “component (D)”). The film-shaped adhesive 10A may further contain a coupling agent (hereinafter, may be referred to as “component (E)”), a curing accelerator (hereinafter, may be referred to as “component (F)”), and the like.
Component (A): Metal Particles
Metal particles as the component (A) constitute a component for increasing the heat dissipation properties when the film-shaped adhesive is applied to a semiconductor device.
Examples of the component (A) include particles including metals such as aluminum, nickel, tin, bismuth, indium, zinc, iron, copper, silver, gold, palladium, and platinum. The component (A) may be metal particles composed of one kind of metal or may be metal particles composed of two or more kinds of metals. The metal particles composed of two or more kinds of metals may be metal-coated metal particles in which the surface of metal particles is coated with a metal other than the metal particles. The component (A) may be, for example, conductive particles.
The conductive particles may be, for example, metal particles composed of a metal having an electrical conductivity (0° C.) of 40×106 S/m or higher. By using such conductive particles, the heat dissipation properties can be further improved. Examples of the metal having an electrical conductivity (0° C.) of 40×106 S/m or higher include gold (49×106 S/m), silver (67×106 S/m), and copper (65×106 S/m). The electrical conductivity (0° C.) may be 45×106 S/m or higher or 50×106 S/m or higher. That is, it is preferable that the conductive particles (or metal particles as the component (A)) are metal particles composed of silver and/or copper.
The conductive particles may be, for example, metal particles composed of a metal having a thermal conductivity (20° C.) of 250 W/m·K or higher. By using such conductive particles, the heat dissipation properties can be further improved. Examples of the metal having a thermal conductivity (20° C.) of 250 W/m·K or higher include gold (295 W/m·K), silver (418 W/m·K), and copper (372 W/m·K). The thermal conductivity (20° C.) may be 300 W/m·K or higher or 350 W/m·K or higher. That is, it is preferable that the conductive particles (or metal particles as the component (A)) are metal particles composed of silver and/or copper.
The component (A) may be silver particles from the viewpoint of being excellent in terms of the electrical conductivity and thermal conductivity and being less likely to be oxidized. The silver particles may be, for example, particles composed of silver (particles composed of silver alone) or silver-coated metal particles in which the surface of metal particles (copper particles or the like) is coated with silver. Examples of the silver-coated metal particles include silver-coated copper particles. The component (A) may be particles composed of silver.
The silver particles as the component (A) are not particularly limited; however, the silver particles may be, for example, silver particles manufactured by a reduction method (silver particles manufactured by a liquid phase (wet type) reduction method using a reducing agent), silver particles manufactured by an atomization method, and the like. The silver particles as the component (A) may be silver particles manufactured by a reduction method.
With regard to the liquid phase (wet type) reduction method using a reducing agent, a surface treatment agent (lubricating agent) is usually added from the viewpoint of controlling the particle size and preventing aggregation and fusion, and silver particles manufactured by the liquid phase (wet type) reduction method using a reducing agent have the surface coated by the surface treatment agent (lubricating agent). For that reason, the silver particles manufactured by a reduction method may be considered as silver particles that are surface-treated with a surface treatment agent. Examples of the surface treatment agent include fatty acid compounds such as oleic acid (melting point: 13.4° C.), myristic acid (melting point: 54.4° C.), palmitic acid (melting point: 62.9° C.), and stearic acid (melting point: 69.9° C.); fatty acid amide compounds such as oleic acid amide (melting point: 76° C.) and stearic acid amide (melting point: 100° C.); aliphatic alcohol compounds such as pentanol (melting point: −78° C.), hexanol (melting point: −51.6° C.), oleyl alcohol (melting point: 16° C.), and stearyl alcohol (melting point: 59.4° C.); and aliphatic nitrile compounds such as oleanitrile (melting point: −1° C.). The surface treatment agent may be a surface treatment agent having a low melting point (for example, a melting point of 100° C. or lower) and high solubility in organic solvents.
The shape of the component (A) is not particularly limited and may be, for example, a flake shape, a resin shape, a spherical shape, or the like and the component (A) may have a spherical shape. When the shape of the component (A) is a spherical shape, the surface roughness (Ra) of the film-shaped adhesive tends to be easily ameliorated.
The component (A) may be metal particles having an average particle size of 0.01 to 10 μm (preferably, conductive particles, and more preferably, silver particles). When the average particle size of the metal particles is 0.01 μm or more, effects such as that an increase in viscosity at the time of producing an adhesive varnish can be prevented, that a desired quantity of metal particles can be incorporated into the film-shaped adhesive, and that more satisfactory adhesiveness can be exhibited by securing the wettability of the film-shaped adhesive on an adherend, tend to be provided. When the average particle size of the metal particles is 10 μm or less, there is a tendency that the film molding properties are more excellent, and the heat dissipation properties brought by addition of metal particles can be further improved. Furthermore, as the average particle size of the metal particles is 10 μm or less, there is a tendency that the thickness of the film-shaped adhesive can be made thinner, semiconductor chips can be more highly laminated, and at the same time, the generation of cracks in semiconductor chips caused by protrusion of metal particles from the film-shaped adhesive can be prevented. The average particle size of the metal particles as the component (A) may be 0.1 μm or more, 0.3 μm or more, or 0.5 μm or more and may be 8.0 μm or less, 7.0 μm or less, 6.0 μm or less, 5.0 μm or less, 4.0 μm or less, or 3.0 μm or less.
Incidentally, according to the present specification, the average particle size of the metal particles as the component (A) means the particle size (laser 50% particle size (D50)) when the ratio (volume ratio) of the metal particles as the component (A) with respect to the total volume of metal particles is 50%. The average particle size (D50) can be determined by measuring a suspension obtained by suspending metal particles in water by a laser scattering method using a laser scattering type particle size measuring apparatus (for example, MicroTrac).
The content of the component (A) may be 70.0% by mass or more based on the total amount of the component (A), component (B), component (C), and component (D), and the content may be 71.0% by mass or more, 72.0% by mass or more, 73.0% by mass or more, 74.0% by mass or more, 74.5% by mass or more, 75.0% by mass or more, or 75.5% by mass or more. When the content of the component (A) is 70.0% by mass or more based on the total amount of the component (A), component (B), component (C), and component (D), there is a tendency that the thermal conductivity of the film-shaped adhesive can be improved, and the heat dissipation properties of the semiconductor can be further improved. The content of the component (A) may be, for example, 85.0% by mass or less, 82.0% by mass or less, 81.0% by mass or less, or 80.0% by mass or less, based on the total amount of the component (A), component (B), component (C), and component (D). When the content of the component (A) is 85.0% by mass or less based on the total amount of the component (A), component (B), component (C), and component (D), other components can be more sufficiently incorporated into the film-shaped adhesive. As a result, there is a tendency that the shear viscosity and loss modulus at 110° C. of the film-shaped adhesive can be easily adjusted to predetermined ranges, and the film-shaped adhesive has more excellent level difference embedding properties.
The content of the component (A) may be 20.0% by volume or more based on the total amount of the component (A), component (B), component (C), and component (D), and the content may be 21.0% by volume or more, 22.0% by volume or more, 22.5% by volume or more, 23.0% by volume or more, 23.5% by volume or more, 24.0% by volume or more, 24.5% by volume or more, 24.8% by volume or more, or 25.0% by volume or more. When the content of the component (A) is 20.0% by volume or more based on the total amount of the component (A), component (B), component (C), and component (D), there is a tendency that the thermal conductivity of the film-shaped adhesive can be improved, and the heat dissipation properties of a semiconductor device can be further improved. When the content of the component (A) may be, for example, 33.0% by volume or less, 31.0% by volume or less, 30.0% by volume or less, or 29.0% by volume or less, based on the total amount of the component (A), component (B), component (C), and component (D). When the content of the component (A) is 33.0% by volume or less based on the total amount of the component (A), component (B), component (C), and component (D), other components can be more sufficiently incorporated into the film-shaped adhesive. As a result, there is a tendency that the shear viscosity and loss modulus at 110° C. of the film-shaped adhesive can be easily adjusted to predetermined ranges, and the film-shaped adhesive has more excellent level difference embedding properties.
The content (% by volume) of the component (A) can be calculated from the following Formula (I), for example, when the density of the film-shaped adhesive is designated as x (g/cm3), the density of the component (A) is designated as y (g/cm3), and the mass proportion of the component (A) in the film-shaped adhesive is designated as z (% by mass). Incidentally, the mass proportion of the component (A) in the film-shaped adhesive can be determined by, for example, performing a thermogravimetric analysis using a thermogravimetric differential thermal analysis apparatus (TG-DTA). Furthermore, the densities of the film-shaped adhesive and the component (A) can be determined by measuring masses and specific gravities using a gravimeter.
Content of component (A) (% by volume)=(x/y)×z (I)
Component (B): Thermosetting Resin
Component (B) is a component having a property of forming three-dimensional bonds between molecules and curing as a result of heating or the like and is a component exhibiting an adhesive action after curing. The component (B) may be an epoxy resin. Regarding the epoxy resin, any resin having epoxy groups in the molecule can be used without particular limitation. The epoxy resin may be a resin having two or more epoxy groups in the molecule.
Examples of the epoxy resin include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a bisphenol A novolac type epoxy resin, a bisphenol F novolac type epoxy resin, a stilbene type epoxy resin, a triazine skeleton-containing epoxy resin, a fluorene skeleton-containing epoxy resin, a triphenolmethane type epoxy resin, a biphenyl type epoxy resin, a xylylene type epoxy resin, a biphenylaralkyl type epoxy resin, a naphthalene type epoxy resin, a dicyclopentadiene type epoxy resin, a polyfunctional phenol, and a diglycidyl ether compound of a polycyclic aromatic compound such as anthracene.
The epoxy resin may include an epoxy resin having a softening point of 90° C. or lower. By including an epoxy resin having a softening point of or lower, the epoxy resin is sufficiently liquefied at 110° C., and thus the shear viscosity and loss modulus at 110° C. of the film-shaped adhesive tend to be easily adjustable to predetermined ranges.
Incidentally, in the present specification, the softening point means a value that is measured by a ring and ball method according to JIS K7234.
The epoxy resin may include an epoxy resin that is liquid at 25° C. There is a tendency that by including such an epoxy resin as the epoxy resin, the surface roughness (Ra) of the film-shaped adhesive is likely to be ameliorated. Examples of a commercially available product of the epoxy resin that is liquid at 25° C. include EXA-830CRP (trade name, manufactured by DIC Corporation) and YDF-8170 (trade name, NIPPON STEEL Chemical & Material Co., Ltd.).
The epoxy equivalent of the epoxy resin is not particularly limited and may be 90 to 300 g/eq or 110 to 290 g/eq. When the epoxy equivalent of the epoxy resin is in such a range, there is a tendency that the fluidity of an adhesive varnish when forming a film-shaped adhesive is easily secured while maintaining the bulk strength of the film-shaped adhesive.
The content of the component (B) may be 1.0% by mass or more, 3.0% by mass or more, 5.0% by mass or more, or 7.0% by mass or more, and may be 15.0% by mass or less, 14.0% by mass or less, 13.0% by mass or less, 12.0% by mass or less, or 11.0% by mass or less, based on the total amount of the component (A), component (B), component (C), and component (D).
Component (C): Curing Agent
Component (C) is a component acting as a curing agent of the component (B). When the component (B) is an epoxy resin, the component (C) may be an epoxy resin curing agent. Examples of the component (C) include a phenol resin (phenol-based curing agent), an acid anhydride-based curing agent, an amine-based curing agent, an imidazole-based curing agent, a phosphine-based curing agent, an azo compound, and an organic peroxide. When the component (B) is an epoxy resin, the component (C) may be a phenol resin from the viewpoints of handleability, storage stability, and curability.
Regarding the phenol resin, any resin having phenolic hydroxyl groups in the molecule can be used without particular limitation. Examples of the phenol resin include a novolac type phenol resin obtainable by condensing or co-condensing a phenol such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, or aminophenol, and/or a naphthol such as α-naphthol, β-naphthol, or dihydroxynaphthalene, with a compound having an aldehyde group, such as formaldehyde, in the presence of an acidic catalyst; a phenol aralkyl resin synthesized from a phenol and/or a naphthol, such as allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolac, or phenol, and dimethoxy-para-xylene or bis(methoxymethyl)biphenyl; a naphthol aralkyl resin, a biphenyl aralkyl type phenol resin, and a phenyl aralkyl type phenol resin.
The phenol resin may include a phenol resin having a softening point of 90° C. or lower. When a phenol resin having a softening point of 90° C. or lower is included, since a phenol resin is sufficiently liquefied at 110° C. there is a tendency that the shear viscosity and loss modulus at 110° C. of the film-shaped adhesive are easily adjusted to predetermined ranges.
The hydroxyl group equivalent of the phenol resin may be 40 to 300 g/eq, 70 to 290 g/eq, or 100 to 280 g/eq. When the hydroxyl group equivalent of the phenol resin is 40 g/eq or more, the storage modulus of the film-shaped adhesive tends to be further improved, and when the hydroxyl group equivalent is 300 g/eq or less, it is possible to prevent defects caused by foaming, occurrence of outgassing, and the like.
The ratio of the epoxy equivalent of the epoxy resin as the component (B) and the hydroxyl group equivalent of the phenol resin as the component (C) (epoxy equivalent of epoxy resin as component (B)/hydroxyl group equivalent of phenol resin as component (C)) may be to 0.70/0.30, 0.35/0.65 to 0.65/0.35, 0.40/0.60 to 0.60/0.40, or 0.45/0.55 to 0.55/0.45, from the viewpoint of curability. When this equivalent ratio is 0.30/0.70 or more, more sufficient curability tends to be obtained. When this equivalent ratio is 0.70/0.30 or less, an excessive increase of viscosity can be prevented, and more sufficient fluidity can be obtained.
The content of the component (C) may be 1.0% by mass or more, 3.0% by mass or more, 4.0% by mass or more, or 5.0% by mass or more, and 15.0% by mass or less, 12.0% by mass or less, 10.0% by mass or less, or 9.0% by mass or less, based on the total amount of the component (A), component (B), component (C), and component (D).
The total content of the component (B) and component (C) may be 13.0% by mass or more based on the total amount of the component (A), component (B), component (C), and component (D). When the total content of the component (B) and component (C) is 13.0% by mass or more based on the total amount of the component (A), component (B), component (C), and component (D), the shear viscosity and loss modulus at 110° C. of the film-shaped adhesive are easily adjusted to predetermined ranges, and the film-shaped adhesive tends to have more excellent level difference embedding properties. The total content of the component (B) and component (C) may be 13.2% by mass or more, 13.5% by mass or more, 14.0% by mass or more, 14.5% by mass or more, 15.0% by mass or more, or 15.5% by mass or more, based on the total amount of the component (A), component (B), component (C), and component (D). The total content of the component (B) and component (C) may be 30.0% by mass or less, 25.0% by mass or less, 23.0% by mass or less, 22.0% by mass or less, 21.0% by mass or less, 20.0% by mass or less, or 18.0% by mass or less, based on the total amount of the component (A), component (B), component (C), and component (D).
Component (D): Elastomer
Examples of component (D) include a polyimide resin, an acrylic resin, a urethane resin, a polyphenylene ether resin, a polyetherimide resin, a phenoxy resin, and a modified polyphenylene ether resin. The component (D) may be one of these resins while being a resin having a crosslinkable functional group or may be an acrylic resin having a crosslinkable functional group. Here, the acrylic resin means a (meth)acrylic (co)polymer including a constituent unit derived from (meth)acrylate ((meth)acrylic acid ester). The acrylic resin may be a (meth)acrylic (co)polymer including a constituent unit derived from a (meth)acrylate having a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxy group. Furthermore, the acrylic resin may be an acrylic rubber such as a copolymer of (meth)acrylate and acrylonitrile. These elastomers may be used singly or in combination of two or more kinds thereof.
Examples of a commercially available product of the acrylic resin include SG-P3, SG-70L, SG-708-6, WS-023 EK30, SG-280 EK23, HTR-860P-3, HTR-860P-3CSP, and HTR-860P-3CSP-3DB (all manufactured by Nagase ChemteX Corporation).
The glass transition temperature (Tg) of the elastomer as the component (D) may be −50° C. to 50° C. or −30° C. to 20° C. When Tg is −50° C. or higher, since tackiness of the film-shaped adhesive is lowered, handleability tends to be further improved. When Tg is 50° C. or lower, there is a tendency that fluidity of an adhesive varnish when forming the film-shaped adhesive can be more sufficiently secured. Here, the Tg of the elastomer as the component (D) means a value measured by using a DSC (thermal differential scanning calorimeter) (for example, manufactured by Rigaku Corporation, trade name: Thermo Plus 2).
The weight average molecular weight (Mw) of the elastomer as the component (D) may be 50000 to 1600000, 100000 to 1400000, or 300000 to 1200000. When the glass transition temperature of the elastomer as the component (D) is 50000 or more, the film-forming properties tend to be more excellent. When the weight average molecular weight of the component (D) is 1600000 or less, fluidity of an adhesive varnish when forming the film-shaped adhesive tends to be more excellent. Here, the Mw of the elastomer as the component (D) means a value measured by gel permeation chromatography (GPC) and converted by using a calibration curve based on polystyrene standards.
The measuring apparatus, measurement conditions, and the like for the Mw of the elastomer as the component (D) are, for example, as follows.
The content of the component (D) may be 15.0% by mass or less, 12.0% by mass or less, 10.0% by mass or less, or 9.0% by mass or less, based on the total amount of the component (A), component (B), component (C), and component (D). When the content of the component (D) is 15.0% by mass or less based on the total amount of the component (A), component (B), component (C), and component (D), an excessive increase in viscosity causing deterioration in the level difference embedding properties can be prevented. From the viewpoint of film processability, the lower limit of the content of the component (D) may be 1.0% by mass or more, 1.5% by mass or more, 2.0% by mass or more, 2.5% by mass or more, or 2.8% by mass or more, based on the total amount of the component (A), component (B), component (C), and component (D).
Component (E): Coupling Agent
Component (E) may be a silane coupling agent. Examples of the silane coupling agent include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane.
Component (F): Curing Accelerator
Examples of component (F) include an imidazole and derivatives thereof, an organophosphorus-based compound, a secondary amine, a tertiary amine, and a quaternary ammonium salt. Among these, from the viewpoint of reactivity, the component (F) may be an imidazole and derivatives thereof.
Examples of the imidazole include 2-methylimidazole, 1-benzyl-2-methylimidayole, 1-cyanoethyl-2-phenylimidayole, and 1-cyanoethyl-2-methylimidazole. These may be used singly or in combination of two or more kinds thereof.
The film-shaped adhesive may further contain other components. Examples of the other components include a pigment, an ion scavenger, and an oxidation inhibitor.
The total content of the component (E), component (F), and other components may be 0.005% to 10% by mass based on the total mass of the film-shaped adhesive.
Another embodiment of the film-shaped adhesive contains component (A), component (B), component (C), and component (D). The content of the component (A) based on the total amount of the component (A), component (B), component (C), and component (D) is 74.5% by mass or more, and the total content of the component (B) and component (C) is 13.0% by mass or more. With regard to the film-shaped adhesive of the present embodiment, the type, content, and the like of each component are similar to the type, content, and the like of each component mentioned as an example in the above-described embodiment. Furthermore, with regard to the film-shaped adhesive of the present embodiment, the preferred ranges of the shear viscosity and loss modulus at 110° C. are also similar to the preferred ranges of the shear viscosity and loss modulus at 110° C. mentioned as an example in the above-described embodiment.
[Method for Manufacturing Film-Shaped Adhesive]
A method for manufacturing the film-shaped adhesive 10A shown in
(Mixing Step)
The mixing step is mixing a raw material varnish containing component (A) and an organic varnish and preparing an adhesive varnish containing component (A), an organic solvent, component (B), and component (C).
The organic solvent is not particularly limited as long as it can dissolve the components other than the component (A). Examples of the organic solvent include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; aliphatic hydrocarbons such as hexane and heptane; cyclic alkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, γ-butyrolactone, butyl carbitol acetate, and ethyl carbitol acetate; carbonic acid esters such as ethylene carbonate and propylene carbonate; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; and alcohols such as butyl carbitol and ethyl carbitol. These may be used singly or in combination of two or more kinds thereof. Among these, from the viewpoints of the solubility of surface treatment agents and the boiling point, the organic solvent may be N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, butyl carbitol, ethyl carbitol, butyl carbitol acetate, ethyl carbitol acetate, or cyclohexanone. The solid component concentration in the raw material varnish may be 10% to 80% by mass based on the total mass of the raw material varnish.
The raw material varnish can be obtained by, for example, adding each component into a container that is used with a stirrer. In this case, the order of addition of each component is not particularly limited and can be appropriately set according to the properties of each component. Mixing can be performed by appropriately combining conventional
stirrers such as a homodisper, a three-one motor, a mixing rotor, a planetary, and a Raikai mixer. The stirrers may include a heating facility such as a heater unit capable of managing the temperature conditions for the raw material varnish or the adhesive varnish. When a homodisper is used for mixing, the speed of rotation of the homodisper may be 4000 rotations/min or higher.
The mixing temperature of the mixing step is not particularly limited but may be 50° C. or higher. Regarding the mixing temperature of the mixing step, heating may be performed using a heating facility or the like as necessary. According to an investigation of the inventors of the present disclosure, it was found that when the mixing temperature of the mixing step is 50° C. or higher, for example, in the case of using silver particles (preferably, silver particles manufactured by a reduction method), the film-shaped adhesive thus obtained may include a sintered body of silver particles in the C-stage state. Such a phenomenon is exhibited more notably when silver particles manufactured by a reduction method are used as the component (A). The reason why such a phenomenon is exhibited is not necessarily obvious; however, the inventors of the present disclosure presume the reason as follows. Silver particles (manufactured by a liquid phase (wet type) reduction method using a reducing agent) as the component (A) usually have the surface coated with a surface treatment agent (lubricating agent). Here, it is speculated that when the mixing temperature of the mixing step is 50° C. or higher, the surface treatment agent covering the silver particles is dissociated (being in a reduced state), and the silver surface is likely to be exposed. In addition, since such silver particles with exposed silver surface are likely to come into direct contact with each other, it is speculated that when the silver particles are heated under the conditions that cure the film-shaped adhesive, the silver particles are sintered together and easily form a sintered body of the silver particles. As a result, it is conceived that the film-shaped adhesive includes a sintered body of silver particles in the C-stage state. In addition, silver particles manufactured by an atomization method are covered with a silver oxide film on the surface of the silver particles due to the characteristics of the manufacturing method therefor. According to an investigation of the inventors of the present disclosure, it was confirmed that in a case where silver particles manufactured by an atomization method are used, even when the mixing temperature of the mixing step is 50° C. or higher, the film-shaped adhesive thus obtained is less likely to include a sintered body of silver particles in the C-stage state. The mixing temperature of the mixing step may be 55° C. or higher, 60° C. or higher, 65° C. or higher, or 70° C. or higher. The upper limit of the mixing temperature of the mixing step may be, for example, 120° C. or lower, 100° C. or lower, or 80° C. or lower. The mixing time of the mixing step may be, for example, 1 minute or more, 5 minutes or more, or minutes or more and may be 60 minutes or less, 40 minutes or less, or 20 minutes or less.
The component (B), component (C), component (D), component (E), component (F), or other components can be incorporated into the adhesive varnish in any stage according to the properties of each component. These components may be incorporated into the adhesive varnish by, for example, adding the components to the raw material varnish before the mixing step or may be incorporated by adding the components to the adhesive varnish after the mixing step. It is preferable that the component (B) and component (C) are incorporated into the adhesive varnish by adding the components to the raw material varnish before the mixing step. The component (D) may be incorporated into the adhesive varnish by adding the component to the raw material varnish before the mixing step or may be incorporated by adding the component to the adhesive varnish after the mixing step. It is preferable that the component (E) and component (F) are incorporated by adding the components to the adhesive varnish after the mixing step. In a case where the components are added to the adhesive varnish after the mixing step, the components may be mixed after addition under, for example, temperature conditions of below 50° C. (for example, room temperature (25° C.)). The conditions in this case may be 0.1 to 48 hours at room temperature (25° C.).
According to an embodiment, the mixing step may be mixing a raw material varnish containing component (A), component (B), component (C), component (D), and an organic solvent preferably at a mixing temperature of 50° C. or higher and preparing an adhesive varnish containing the component (A), the component (B), the component (C), the component (D), and the organic solvent.
In this manner, an adhesive varnish containing the component (A), an organic solvent, the component (B), and the component (C) can be prepared. With regard to the adhesive varnish, gas bubbles in the varnish may be removed by means of vacuum degassing or the like after preparation.
The solid component concentration in the adhesive varnish may be 10% to 80% by mass based on the total mass of the adhesive varnish.
(Formation Step)
The formation step is forming a film-shaped adhesive by using the adhesive varnish. Examples of a method for forming a film-shaped adhesive include a method of applying the adhesive varnish on a support film.
Regarding the method of applying the adhesive varnish on a support film, a known method can be used, and examples include a knife coating method, a roll coating method, a spray coating method, a gravure coating method, a bar coating method, and a curtain coating method.
After the adhesive varnish is applied on the support film, the organic solvent may be heated and dried as necessary. Heating and drying are not particularly limited as long as the processes are carried out under the conditions in which the organic solvent used is sufficiently volatilized; however, for example, the heating and drying temperature may be 50° C. to 200° C., and the heating and drying time may be 0.1 to 30 minutes. Heating and drying may be carried out stepwise at different heating and drying temperatures or heating and drying times.
In this manner, the film-shaped adhesive 10A can be obtained. The thickness of the film-shaped adhesive 10A can be appropriately adjusted according to the use application; however, for example, the thickness may be 3 μm or more, 5 μm or more, or 10 μm or more, and may be 200 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less.
In the C-stage state, the thermal conductivity (25° C.±1° C.) of the film-shaped adhesive 10A may be 1.5 W/m·K or greater. When the thermal conductivity is 1.5 W/m·K or greater, the heat dissipation properties of the semiconductor device tend to be more excellent. The thermal conductivity may be 2.0 W/m·K or greater, 2.5 W/m·K or greater, 3.0 W/m·K or greater, 3.5 W/m·K or greater, 4.0 W/m·K or greater, 4.5 W/m·K or greater, or 5.0 W/m·K or greater. The upper limit of the thermal conductivity (25° C.±1° C.) of the film-shaped adhesive 10A in the C-stage state is not particularly limited; however, the upper limit may be 30 W/m·K or less. Incidentally, according to the present specification, the thermal conductivity means a value calculated by the method described in Examples. Furthermore, the conditions for curing the film-shaped adhesive 10A to be in the C-stage state can be set to, for example, a heating temperature of 170° C. and a heating time of 3 hours.
[Dicing-Die Bonding Integrated Film and Method for Manufacturing the Same]
Examples of the base material layer 40 in the dicing tape 50 include plastic films such as a polytetrafluoroethylene film, a polyethylene terephthalate film, a polyethylene film, a polypropylene film, a polymethylpentene film, and a polyimide film. Furthermore, the base material layer 40 may be subjected to a surface treatment such as primer application, a UV treatment, a corona discharge treatment, a polishing treatment, or an etching treatment, as necessary.
The pressure-sensitive adhesive layer 30 in the dicing tape 50 is not particularly limited as long as the pressure-sensitive adhesive layer has an adhesive strength that is sufficient not to allow scattering of semiconductor chips at the time of dicing and an adhesive strength that is low to the extent that semiconductor chips are not damaged in the subsequent step of picking up the semiconductor chips, and pressure-sensitive adhesive layers which are conventionally known in the field of dicing tapes can be used. The pressure-sensitive adhesive layer 30 may be a non-ultraviolet curable pressure-sensitive adhesive layer formed from a non-ultraviolet curable pressure-sensitive adhesive or may be an ultraviolet curable pressure-sensitive adhesive layer formed from an ultraviolet curable pressure-sensitive adhesive. When the pressure-sensitive adhesive layer is an ultraviolet curable pressure-sensitive adhesive layer formed from an ultraviolet curable pressure-sensitive adhesive, the adhesiveness of the pressure-sensitive adhesive layer can be lowered by irradiating the pressure-sensitive adhesive layer with ultraviolet radiation.
The thickness of the dicing tape 50 (base material layer 40 and adhesive layer 30) may be 60 to 150 μm or 70 to 130 μm from the viewpoints of economic efficiency and film handleability.
The dicing-die bonding integrated film 100 shown in
[Method for Manufacturing Semiconductor Device]
<Wafer Lamination Step>
In the present step, first, the dicing-die bonding integrated film 100 is disposed in a predetermined apparatus. Subsequently, the surface Ws of a semiconductor wafer W is stuck to the bonding adhesive layer 10 of the dicing-die bonding integrated film 100 (see
Examples of the semiconductor wafer W include single crystal silicon, polycrystal silicon, various ceramics, and compound semiconductors such as gallium arsenide.
<Dicing Step>
In the present step, the semiconductor wafer W and the bonding adhesive layer 10 are diced to be singulated (see
<Ultraviolet Irradiation Step>
When the pressure-sensitive adhesive layer 30 is an ultraviolet-curable adhesive layer, the method for manufacturing a semiconductor device may include an ultraviolet irradiation step. In the present step, the pressure-sensitive adhesive layer 30 is irradiated with ultraviolet radiation (through the base material layer 40) (see
<Pickup Step>
In the present step, while the singulated adhesive piece-attached semiconductor chips 60 are separated apart from each other by expanding the base material layer 40, the adhesive piece-attached semiconductor chips that have been thrusted up by a needle 72 from the base material layer 40 side are sucked by a suction collet 74 and picked up from the pressure-sensitive adhesive layer 30a (see
The thrust-up quantity exerted by the needle 72 can be set as appropriate. In addition, from the viewpoint of securing sufficient pickup properties even for an ultrathin wafer, for example, two stages or three stages of thrust-up may be performed. Furthermore, the adhesive piece-attached semiconductor chips 60 may be picked by a method other than the method of using a suction collet 74.
<Semiconductor Chip Adhesion Step>
In the present step, an adhesive piece-attached semiconductor chip thus picked up is adhered to a support member 80 by thermal compression, with the adhesive piece 10a interposed therebetween (see
The heating temperature for the thermal compression may be, for example, 80° C. to 160° C. The load for the thermal compression may be, for example, 5 to 15 N. The heating time for the thermal compression may be, for example, 0.5 to 20 seconds.
<Thermal Curing Step>
In the present step, the adhesive piece 10a in the adhesive piece-attached semiconductor chip 60 adhered to the support member 80 is thermally cured. By (further) thermally curing the adhesive piece 10a adhering the semiconductor chip Wa and the support member 80, or a cured product 10ac of the adhesive piece, stronger adhesive fixation is enabled. Furthermore, when the component (A) is silver particles (preferably, silver particles manufactured by a reduction method), there is a tendency that a sintered body of the silver particles is even more easily obtained by (further) thermally curing the adhesive piece 10a or a cured product 10ac of the adhesive piece. In the case of performing thermal curing, curing may be carried out by simultaneously applying pressure. The heating temperature in the present step can be changed as appropriate depending on the constituent components of the adhesive piece 10a. The heating temperature may be, for example, 60° C. to 200° C. or may be 90° C. to 190° C. or 120° C. to 180° C. The heating time may be 30 minutes to 5 hours or may be 1 to 3 hours or 2 to 3 hours. Incidentally, the heating may be carried out while changing the temperature or pressure stepwise.
The adhesive piece 10a may become a cured product 10ac of the adhesive piece by being cure through the semiconductor chip adhesion step or the thermal curing step. When the component (A) is silver particles (preferably, silver particles manufactured by a reduction method), the cured product 10ac of the adhesive piece may include a sintered body of the silver particles. Therefore, the semiconductor device thus obtained may have excellent heat dissipation properties.
The method for manufacturing a semiconductor device may include, as necessary, electrically connecting a tip of a terminal part (inner lead) of the support member and an electrode pad on a semiconductor element by using a bonding wire (wire bonding step). As the bonding wire, for example, a gold wire, an aluminum wire, a copper wire, and the like are used. The temperature at the time of performing wire bonding may be in the range of 80° C. to 250° C. or 80° C. to 220° C. The heating time may be several seconds to several minutes. Wire bonding may be carried out in a state of being heated within the above-described temperature range, by using the vibration energy of ultrasonic waves and the pressure-bonding energy of applied pressure in combination.
The method for manufacturing a semiconductor device may include, as necessary, encapsulating semiconductor elements by using an encapsulant (encapsulation step). The present step is carried out in order to protect the semiconductor elements or bonding wires mounted on the support member. The present step can be carried out by molding a resin for encapsulation (encapsulation resin) in a mold. The encapsulation resin may be, for example, an epoxy-based resin. Due to the heat and pressure during encapsulation, the support member and residue are embedded, and detachment caused by gas bubbles at the adhesive interface can be prevented.
The method for manufacturing a semiconductor device may include, as necessary, completely curing the encapsulation resin that is insufficiently cured in the encapsulation step (post-curing step). Even in a case where the adhesive piece is not thermally cured in the encapsulation step, the adhesive piece is thermally cured together with curing of the encapsulation resin to enable adhesive fixation in the present step. The heating temperature for the present step can be appropriately set according to the type of the encapsulation resin, and for example, the heating temperature may be in the range of 165° C. to 185° C., while the heating time may be about to 8 hours.
The method for manufacturing a semiconductor device may include, as necessary, heating the adhesive piece-attached semiconductor device adhered to the support member by using a reflow furnace (heating and melting step). In the present step, the resin-encapsulated semiconductor device may be surface-mounted on a support member. Examples of the method for surface mounting include reflow soldering of supplying solder in advance onto a printed wiring board, and then heating and melting solder by means of hot air or the like to perform soldering. Examples of the heating method include hot air reflow and infrared reflow. Furthermore, the heating method may be a method of heating the entirety or may be a method of locally heating. The heating temperature may be, for example, in the range of 240° C. to 280° C.
[Semiconductor Device]
The semiconductor chip Wa (semiconductor element) may be, for example, an IC (integrated circuit). Examples of the support member 80 include lead frames such as an Alloy 42 lead frame and a copper lead frame; plastic films such as a polyimide resin and an epoxy resin; modified plastic films obtained by impregnating a base material such as a glass nonwoven fabric with a plastic such as a polyimide resin or an epoxy resin and curing the plastic; and ceramics such as alumina.
Since the semiconductor device 200 includes a cured product of the above-described film-shaped adhesive as a bonding adhesive member, the semiconductor device 200 has excellent heat dissipation properties.
Hereinafter, the present disclosure will be specifically described based on Examples; however, the present disclosure is not intended to be limited to these.
<Preparation of Adhesive Varnish>
A raw material varnish was prepared by adding cyclohexanone as an organic solvent to component (A), component (B), component (C), and component (D) with the reference symbols and composition ratios (unit: parts by mass) indicated in Table 1 and Table 2. This raw material varnish was stirred for 20 minutes at a rate of 4000 rotations/minute under the mixing temperature conditions of 70° C. by using a homodisper (manufactured by Tajima-K.K., T.K. HOMO MIXER MARK II), and an adhesive varnish was obtained. Next, the adhesive varnish was left to stand until the temperature reached 20° C. to 30° C., subsequently component (E) and component (F) were added to the adhesive varnish, and the mixture was stirred overnight at a rate of 250 rotations/minute by using a three-one motor. In this manner, adhesive varnishes of Examples 1 to 11 and Comparative Examples 1 to 7, in which the total content of the component (A), component (B), component (C), and component (D) was 61% by mass, were prepared.
Incidentally, the reference symbol of each component in Table 1 and Table 2 means the following.
Component (A): Metal Particles
(A-1) Silver particles AG-3-1F (trade name, manufactured by DOWA Electronics Materials Co., Ltd., shape: spherical, average particle size (laser 50% particle size (D50)): 1.5 μm)
(A-2) Silver particles AG-5-1F (trade name, manufactured by DOWA Electronics Materials Co., Ltd., shape: spherical, average particle size (laser 50% particle size (D50)): 2.9 μm)
(A-3) Silver particles AG-2-1C (trade name, manufactured by DOWA Electronics Materials Co., Ltd., shape: spherical, average particle size (laser 50% particle size (D50)): 0.7 μm)
Component (B): Thermosetting Resin
(B-1) N-500P-10 (trade name, manufactured by DIC Corporation, cresol novolac type epoxy resin, epoxy equivalent: 204 g/eq, softening point: 84° C.)
(B-2) EXA-830CRP (trade name, manufactured by DIC Corporation, bisphenol F type epoxy resin, epoxy equivalent: 159 g/eq, liquid at 25° C.)
Component (C): Curing Agent
(C-1) MEH-7800M (trade name, manufactured by Meiwa Kasei Co., Ltd., phenyl aralkyl type phenol resin, hydroxyl group equivalent: 174 g/eq, softening point: 80° C.)
(C-2) PSM-4326 (trade name, manufactured by Gun Ei Chemical Industry Co., Ltd., phenol novolac type phenol resin, hydroxyl group equivalent: 105 g/eq, softening point: 120° C.)
Component (D): Elastomer
(D-1) SG-P3 (trade name, manufactured by Nagase ChemteX Corporation, acrylic rubber, weight average molecular weight: 800000, Tg: −7° C.)
Component (E): Coupling Agent
(E-1) A-1160 (trade name, manufactured by Nippon Unicar Company Limited, γ-ureidopropyltriethoxysilane)
Component (F): Curing Accelerator
(F-1) 2PZ-CN (trade name, manufactured by SHIKOKU CHEMICALS CORPORATION, 1-cyanoethyl-2-phenylimidayole)
<Calculation of Percentage by Volume (% by Volume)>
The content (% by volume) of the component (A) was calculated by the following Formula (I), when the density of the film-shaped adhesive was designated as x (g/cm3), the density of the component (A) was designated as y (g/cm3), and the mass proportion of the component (A) in the film-shaped adhesive was designated as z (% by mass). Incidentally, the mass proportion of the component (A) in the film-shaped adhesive was determined by performing a thermogravimetric analysis by using a thermogravimetric differential thermal analysis (TG-DTA). Furthermore, the densities of the film-shaped adhesive and the component (A) were determined by measuring masses and specific gravities using a gravimeter.
Content (% by volume) of component (A)=(x/y)×z (I)
<Production of Film-Shaped Adhesive>
Film-shaped adhesives were produced by using the adhesive varnishes of Examples 1 to 11 and Comparative Examples 1 to 7. Each adhesive varnish was subjected to vacuum degassing, and the adhesive varnish obtained thereafter was applied on a polyethylene terephthalate (PET) film (thickness: 38 μm) that had been a mold release treatment, which was a support film. The applied adhesive varnish was heated and dried in two stages for 5 minutes at 90° C. and subsequently for 5 minutes at 130° C., and thus, the film-shaped adhesives of Examples 1 to 11 and Comparative Examples 1 to 7, which had a thickness of 25 μm and were in the B-stage state, were obtained on the support film.
<Measurement of Shear Viscosity, Storage Modulus, Loss Modulus, and Tan δ at 110° C. of Film-Shaped Adhesive>
Each of the film-shaped adhesives (thickness: 25 μm) of Examples 1 to 11 and Comparative Examples 1 to 7 was cut into a predetermined size, and twelve sheets of film pieces were prepared. Next, the twelve sheets of the film pieces of film pieces were laminated on a hot plate at 70° C. by using a rubber roll, and a laminated body having a thickness of 300 μm was prepared. Next, the laminated body was punched out using a punch of ϕ9 mm to produce a sample, and for the produced sample, shear viscosity, storage modulus, loss modulus, and tan δ at 110° C. were measured by using a rotary viscoelasticity measuring apparatus (manufactured by TA Instruments Japan Inc., trade name: ARES-RDA) under the following measurement conditions. Incidentally, when setting a gap, the gap was regulated such that the load exerted on the sample was 10 to 15 g. The results are shown in Table 1 and Table 2.
(Measurement Conditions)
<Evaluation of Level Difference Embedding Properties>
(Production of Dicing-Die Bonding Integrated Film)
Dicing-die bonding integrated films of Examples 1 to 11 and Comparative Examples 1 to 7 including a die bonding film and a dicing tape were obtained by preparing a dicing tape including a pressure-sensitive adhesive layer and sticking each of the film-shaped adhesive (thickness: 25 μm) of Examples 1 to 11 and Comparative Examples 1 to 7 to the pressure-sensitive adhesive layer of the dicing tape at 25° C.
(Production of Laminated Body)
The dicing-die bonding integrated films of Examples 1 to 11 and Comparative Examples 1 to 7 were used. A laminated body was obtained by sticking the bonding adhesive layer (film-shaped adhesive) of each of the dicing-die bonding integrated films to a semiconductor wafer (thickness: 100 μm) by using a film laminator (manufactured by Teikoku Taping System Co., Ltd.).
(Production of Sample for Evaluation)
The semiconductor wafer in the obtained laminated body was singulated by dicing into a size of 7.5 mm×7.5 mm, and then singulated adhesive piece-attached semiconductor chips were picked by using a die bonder (manufactured by Besi, Esec2100sD PPP Plus). The pickup conditions were set to an expansion of 3 mm, a thrust-up load of 1 N, a pickup time of 100 ms, and a thrust-up speed of 10 mm/s Next, a stepped substrate having a level difference of 4 μm was prepared, and the adhesive piece-attached semiconductor chips were pressure-bonded to the stepped substrate, with the adhesive piece interposed therebetween, under the conditions including a stage temperature for heating the substrate of 120° C., a pressure-bonding time of 1 second, and a pressure-bonding load of 0.1 MPa. Subsequently, the stepped substrate on which a semiconductor chip was pressure-bonded was subjected to pressurization and heating for one hour under the conditions of a temperature of 110° C. and a pressure of 0.5 MPa and then for 3 hours under the conditions of a temperature of 170° C. and a pressure of 0.5 MPa, and the adhesive piece was thermally cured to obtain a sample for evaluation.
(Evaluation of Level Difference Embedding Properties of Sample for Evaluation)
Evaluation of the level difference embedding properties was carried out by observing the portion between the stepped substrate and the thermally cured adhesive piece by using an ultrasonic imaging apparatus (manufactured by Hitachi Construction Machinery Finetech Co., Ltd., FineSAT series FS2000II). A case in which black shadows as voids between the stepped substrate and the thermally cured adhesive piece were not observed was rated as “A”, and a case in which black shadows as voids were observed was rated as “B”. The results are shown in Table 1 and Table 2.
<Measurement of Thermal Conductivity>
(Production of Film for Thermal Conductivity Measurement)
A plurality of sheets of each of the film-shaped adhesives of Examples 1 to 11 and Comparative Examples 1 to 7 was stuck together using a rubber roll to produce a laminated film having a thickness of 200 μm or more. Next, the laminated film was cut out into a size of 1 cm×1 cm, and the cut laminated film was thermally cured in a clean oven (manufactured by ESPEC CORP.) at 170° C. for 3 hours to obtain a film for thermal conductivity measurement in the C-stage state.
(Calculation of Thermal Conductivity)
The thermal conductivity λ in the thickness direction of the film for thermal conductivity measurement was calculated by the following formula. The results are shown in Table 1 and Table 2.
Thermal conductivity λ (W/m·K)=Thermal diffusivity α (m2/s)×specific heat Cp (J/kg·K)×density ρ (g/cm3)
Incidentally, the thermal diffusivity α, specific heat Cp, and density ρ were measured by the following methods. A higher thermal conductivity λ means that the semiconductor device has more excellent heat dissipation properties.
(Measurement of Thermal Diffusivity α)
A measurement sample was produced by subjecting both surfaces of the film for thermal conductivity measurement to a blackening treatment using a graphite spray. For the measurement sample, the thermal diffusivity α of the film for thermal conductivity measurement was determined by a laser flash method (xenon flash method) under the following conditions by using the following measuring apparatus.
(Measurement of Specific Heat Cp (25° C.))
The specific heat Cp (25° C.) of the film for thermal conductivity measurement was determined by performing differential scanning calorimetry (DSC) under the following conditions by using the following measuring apparatus.
(Measurement of Density ρ)
The density ρ of the film for thermal conductivity measurement was measured by the Archimedes method under the following conditions by using the following measuring apparatus.
As shown in Table 1 and Table 2, the parameters of shear viscosity and loss modulus of the film-shaped adhesives were highly correlated with the quality of the level difference embedding properties, and the film-shaped adhesives of Examples 1 to 11 that contained the component (A) and satisfied either the following condition (i) or condition (ii) had satisfactory thermal conductivity as well as excellent level difference embedding properties, as compared with the film-shaped adhesives of Comparative Examples 1 to 7 that did not satisfy such conditions. On the other hand, it was found that the storage modulus and tan δ (=loss modulus/storage modulus), which are parameters other than the shear viscosity and loss modulus of the film-shaped adhesive, had a low correlation with the quality of the level difference embedding properties.
Furthermore, the film-shaped adhesives of Examples 1 to 11, in which the content of the component (A) based on the total amount of the component (A), component (B), component (C), and component (D) was by mass or more, and the total content of the component (B) and the component (C) was 13.0% by mass or more, had satisfactory thermal conductivity as well as excellent level difference embedding properties, as compared with the film-shaped adhesives of Comparative Examples 1 to 7 that did not satisfy such conditions.
From the above, it was verified that the film-shaped adhesive of the present disclosure enables manufacture of a semiconductor device having excellent heat dissipation properties and has excellent level difference embedding properties.
According to the present disclosure, a film-shaped adhesive that enables manufacture of a semiconductor device having excellent heat dissipation properties and has excellent level difference embedding properties is provided. Furthermore, according to the present disclosure, a dicing-die bonding integrated film that uses such a film-shaped adhesive is provided. In addition, according to the present disclosure, a semiconductor device that uses such a film-shaped adhesive or dicing-die bonding integrated film, and a method for manufacturing the semiconductor device are provided.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/048896 | Dec 2020 | WO | international |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/036499 | 10/1/2021 | WO |
