JP2017197688A - Insulation film for underfill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation film for underfill exhibiting plasticity and flowability in the initial stage of a process for conjugating a semiconductor tip and a substrate and excellent in long term storage stability even after processing curing sufficiently and further heating in the later stage of the process.SOLUTION: There is provided an insulation film for underfill having melt viscosity at 110°C, η, of 1×10to 5×10Pa s, melt viscosity at 130°C, η, of 5×10to 1×10Pa s and a ratio of melt viscosity ηat 130°C after holding at 40°C for 1 hr. and the η, η/ηof less than 3.SELECTED DRAWING: None

Description

  TECHNICAL FIELD The present invention relates to an underfill insulating film (NCF) used for filling a semiconductor chip in a flip-chip mounting process, chip / chip or chip / circuit board, and more specifically, The present invention relates to an insulating film for underfill that has curing characteristics required in such a mounting process and is excellent in storage stability, and uses thereof.

In the mounting of semiconductor chips such as flip chip (FC) mounting, after connecting the semiconductor chip and the circuit board, filling the space between the semiconductor chip and the circuit board with a liquid underfill material has been widely used. (For example, refer to Patent Document 1). Specifically, for example, in a flip chip BGA, a chip with solder bumps is FC-connected to a package substrate, and a liquid underfill is injected and cured.
However, in recent years, in order to increase the signal amount between semiconductor chips, the number of bumps tends to increase, and the chip area is limited, so that the pitch of bumps is becoming narrower. For example, in the advanced field of processors and memories, chips with ultra-multiple bumps are mounted on the silicon interposer in close proximity, or memory chips with many bumps formed on both sides with silicon through electrodes (TSV) are stacked. It has been put to practical use and is expected to spread due to cost reduction.
In addition, the bump height was large in consideration of the relaxation of thermal stress between the chip and the substrate and underfill filling, but in the case of a silicon interposer that supports high-density bumps or a case of stacking silicon chips Since the same silicon material is used, it is not necessary to consider thermal stress, and the narrowing of the gap is also progressing due to the trend of thermal conduction (heat radiation) and low profile of IC packages.
In the filling method using a liquid underfill material, it has become difficult to fill all the air bubbles between the narrow pitch and narrow gap chips. Underfill is required to have functions such as ensuring insulation between bumps and supporting stress generated in the bumps. However, if the filling property is poor, the reliability is lowered in that respect.
In addition, when FC connecting a large chip to a resin substrate, bump connection near the outer periphery may be broken due to thermal stress during reflow or the like, and the yield may be reduced. There has been a demand for a paste or film-like pre-fill material that forms an underfill that supports bumps simultaneously with FC connection.
On the other hand, a flip-chip connection method via an anisotropic conductive film (ACF) has also been put into practical use in the field of liquid crystal driver ICs. However, since this method adds conductive particles to the film, there is a concern of inducing a short circuit between the bumps in the trend of narrowing the pitch of the bumps. In addition, it has been developed to be mounted on a display having no heat resistance, and cannot withstand the reflow temperature, so that it is difficult to apply it to a general-purpose IC package. Due to reliability and cost, it is difficult to adapt to the connection and process by the mainstream solder bumps in recent years. Further, since the light transmittance is poor due to the addition of the conductive particles, the alignment mark cannot be visually recognized when the ACF is applied to the bump surface of the chip, so that the chip and the substrate cannot be aligned. Therefore, there is also a problem that a bonding film cannot be used as a chip with a bonding material by bonding a bonding film on the bump surface at the wafer level and dividing it into individual pieces.
Also, the paste underfill material (NCP) is placed between the chip and the substrate before bonding, and it is difficult to control the protrusion of the resin, and when stacking chips or placing chips close to each other In addition, it becomes difficult to apply.
As described above, NCF is considered to be a promising bonding material in the field of FC mounting of bump chips with narrow pitches and narrow gaps, IC packages in which the chips are FC mounted close to each other, and FC mounting on resin substrates of large chips. ing.

A resin film is used as an insulating film for underfill, and is disposed between the semiconductor chip and the substrate. Then, when the semiconductor chip and the substrate are FC-bonded by heating / loading, the resin flows and the semiconductor chip A technique for filling a space between substrates has been proposed (see, for example, Patent Document 2).
In the insulating film for underfill, the resin constituting the insulating film fills the narrow space between the semiconductor chip and the circuit board without any gaps, and good conduction between the electrode on the semiconductor chip side and the electrode on the board side It is necessary to show fluidity so as not to disturb. On the other hand, when such a resin having fluidity is rapidly heated to the solder melting temperature, it is required to prevent generation of voids.
Further, as to which side of the chip or substrate the NCF is to be attached, from the viewpoint of bonding the chip and the substrate without voids, the substrate with less unevenness is applied to the chip side where bumps are more prominent. It is more advantageous than sticking first to the side.
In addition, it is preferable from the viewpoint of simplifying the process that the NCF and the chip are singulated into the same size by attaching the NCF to the wafer, rather than attaching the NCF to an appropriate position on the substrate side and further pressing the chip there. . Therefore, there is an attractive method in which NCF is pasted on a wafer, singulated to obtain a chip with NCF, and FC-connected to the substrate.
When FC mounting is performed through a process of obtaining a chip with NCF by dividing into pieces by attaching NCF to a wafer, NCF is attached to a semiconductor wafer for reasons such as switching of brands or schedules of manufacturing equipment. In some cases, it may be stored at room temperature for a relatively long period of about 1 to 2 months. However, according to the study by the present inventors, the NCF that is thermosetting as described above gradually undergoes a curing reaction even at room temperature. There was a risk of poor conduction and poor conduction.
Also, as a method of sticking air to the bump surface of the chip without air entrainment, a method of sticking NCF to the wafer with a vacuum heat sticking machine is excellent. However, in such a device, the set vacuum degree is set in a heated environment. NCF is placed under hypoxia until it reaches. In the radical curing system that is promising as the thermosetting system described above, oxygen inhibits the reaction, so that stability can be ensured. However, when heated in a vacuum, the reaction proceeds and the flowability of NCF is low. It is thought that it will fall.
Thus, there has been a demand for an insulating film for underfill that has a curing characteristic capable of satisfactorily bonding a semiconductor chip and a circuit board and the like and has excellent storage stability.

JP-A-10-158366 JP 2007-107006 A

In view of the above background art, the problem to be solved by the present invention is the problem that voids are generated when soldering NCF is rapidly heated to the vicinity of the solder melting temperature. The problem is that the problem of causing the conduction failure is solved, and adjustment is made so as to cure appropriately by rapid heating within a limited tact time in consideration of productivity and cost.
In the present invention, in the wafer process described above, the process of vacuum heating and bonding to the bump surface of the wafer with bumps, the process of separating the wafer with NCF into individual chips to form chips with NCF, and the FC connection process are performed. Depending on the plan, about one month may elapse. It is another object of the present invention to provide an NCF that maintains good fluidity and curing characteristics at an initial stage even after such processes and storage and enables a good FC connection.

As a result of intensive studies to solve the above problems, the present inventors have focused on the melt viscosity η ^* of the film at a specific temperature, and more specifically, the melt viscosity η ^* ₁ at 110 ° C., 130 ° C. The above problem is effectively solved when the melt viscosity η ^* ₂ at 130 ° C and the melt viscosity η ^* ₃ at 130 ° C after storage at 40 ° C for 1 week are in a specific range and relationship, respectively. As a result, the present invention has been completed.
That is, the present invention and each embodiment thereof are as described in [1] to [15] below.

[1]
The melt viscosity η ^* ₁ at 110 ° C. is 1 × 10 ^{1 to} 5 × 10 ³ Pa · s,
The melt viscosity η ^* ₂ at 130 ° C. is 5 × 10 ² to 1 × 10 ⁵ Pa · s, and
An insulating film for underfill in which the ratio η ^* ₃ / η ^* ₂ of the melt viscosity η ^* ₃ at 130 ° C. after being held at 40 ° C. for 1 week and the above η ^* ₂ is less than 3.
[2]
The insulating film for underfill according to [1], wherein the content of conductive particles is 5% by mass or less.
[3]
It contains a resin for film formation, a thermal radical polymerizable substance, a thermal radical generator, a polymerization inhibitor and a flux, and the content (mass) of the polymerization inhibitor is the amount (mass) of the thermal radical polymerizable substance. On the other hand, the insulating film for underfill according to [1] or [2], which is 600 to 10000 ppm.
[4]
The insulating film for underfill according to [3], wherein the thermal radical generator has a one-minute half-life temperature of 140 to 200 ° C.
[5]
The insulating film for underfill according to [3], wherein the polymerization inhibitor is a quinone.
[6]
The insulating film for underfill according to any one of [3] to [5], further comprising an epoxy resin and a latent curing agent.
[7]
The initial latent curing agent is 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2,4-diamino-6- [2′-methylimidazolyl- ( 1 ′)]-Ethyl-s-triazine isocyanuric acid adduct, The insulating film for underfill according to [6], which is at least one selected from adducts.
[8]
An exothermic curve in the range of 50 to 250 ° C. measured by a differential scanning calorimeter has a maximum value in the range of 130 to 170 ° C., and at least one exothermic peak has a half width of 25 to 60 ° C. [ The insulating film for underfill according to any one of [1] to [7].
[9]
The insulating film for underfill according to any one of [1] to [8], wherein an exothermic curve in a range of 50 to 250 ° C measured with a differential scanning calorimeter has at least two maximum values.
[10]
The insulating film for underfill according to any one of [1] to [9], wherein a semiconductor chip on which a soldered electrode is formed and a circuit board on which a counter electrode facing the soldered electrode is formed. A method of manufacturing a semiconductor device, wherein
a) a step of applying the underfill insulating film on a wafer having a soldered electrode under vacuum;
b) dividing the wafer into individual semiconductor chips with an insulating film for underfill;
c) With the semiconductor chip and the circuit board, the electrode of the semiconductor chip and the counter electrode of the circuit board are respectively substantially abbreviated in a temperature condition where the maximum temperature is equal to or higher than the melting point temperature of the solder mounted on the chip. And a thermocompression bonding step of thermocompression bonding so as to contact on the center line.
[11]
A semiconductor chip on which a soldered electrode is formed, an underfill insulating film according to any one of [1] to [9], and a circuit board on which a counter electrode facing the soldered electrode is formed. A laminated body joined in order,
The laminated body, wherein at least a part of the soldered electrode is in electrical contact with at least a part of the counter electrode.
[12]
In a place where at least a part of the soldered electrode is in electrical contact with at least a part of the counter electrode, the under electrode is interposed between at least a part of the soldered electrode and at least a part of the counter electrode. The laminate according to [11], wherein there is no insulating film for fill.
[13]
The through-hole is formed in the insulating film for underfill at a location where at least a part of the soldered electrode is in electrical contact with at least a part of the counter electrode. Laminated body.
[14]
[11] A semiconductor device comprising the laminate according to any one of [13].
[15]
[14] An electric / electronic apparatus having the semiconductor device according to [14].

According to the present invention, in the initial stage of the process of joining the semiconductor chip and the wiring board, good fluidity is achieved by exhibiting sufficient fluidity, and in the later stage of the process, the curing proceeds sufficiently. Voids are suppressed, and even after pasting the underfill insulating film on a semiconductor wafer, for example, it has excellent storage stability for a long time. In the mounting of a semiconductor chip such as flip chip mounting, it is particularly preferably used when bonding the semiconductor chip and the circuit board.
The method for producing a semiconductor device using the underfill insulating film of the present invention is excellent in productivity and performance of the produced semiconductor device.
By using the underfill insulating film of the present invention, it is possible to manufacture a semiconductor device having excellent performance, intermediate products and applied products thereof with high productivity.

It is sectional drawing which shows typically the semiconductor chip before the process b) in the method which is one Embodiment of this invention, a circuit board, and the insulating film for underfills. It is sectional drawing which shows typically the semiconductor chip, the circuit board, and the insulating film for underfills in the process b) initial stage in the method which is one Embodiment of this invention. It is sectional drawing which shows typically the semiconductor chip, the circuit board, and the insulating film for underfills in the process b) late stage in the method which is one Embodiment of this invention. It is sectional drawing which shows typically the semiconductor chip, the circuit board, and the insulating film for underfills after the process b) in the method which is one Embodiment of this invention.

(Insulating film for underfill)
The underfill insulating film of the present invention is an underfill insulating film suitably used for bonding a semiconductor chip on which a soldered electrode is formed and a circuit board on which a counter electrode facing the soldered electrode is formed. A film,
The melt viscosity η ^* ₁ at 110 ° C. is 1 × 10 ^{1 to} 5 × 10 ³ Pa · s,
The melt viscosity η ^* ₂ at 130 ° C. is 5 × 10 ² to 1 × 10 ⁵ Pa · s, and
The ratio η ^* ₃ / η ^* ₂ the melt viscosity eta ^* ₃ and the eta ^* ₂ at 130 ° C. after held for 1 week at 40 ° C. is less than 3, an insulating film for the underfill.

The melt viscosity η ^* can be measured by using a rheometer (dynamic viscoelasticity measuring device (shear)) and raising the temperature at 10 ° C./min under nitrogen at a frequency of 1 Hz.
The melt viscosity η ^* ₃ at 130 ° C. after being held at 40 ° C. for 1 week was not measured for the melt viscosity η ^* ₁ at 110 ° C. and the melt viscosity η ^* ₂ at 130 ° C. (η ^* ₁ and a sample having no thermal history by measurement of η ^* ₂ . Therefore, in measuring the melt viscosities η ^* ₁ , η ^* ₂ , and η ^* ₃ , it is a sample obtained under the same composition and production conditions, and includes at least one sample for measuring η ^* ₁ and η ^* ₂ A plurality of samples including a sample and at least one sample for η ^* ₃ measurement are prepared.
When the melt viscosity η ^* ₁ at 110 ° C. is 1 × 10 ¹ Pa · s or more, it is preferable from the viewpoint of preventing excessive protrusion and resin creeping. The melt viscosity η ^* ₁ at 110 ° C. is more preferably 1 × 10 ² Pa · s or more, and particularly preferably 5 × 10 ² Pa · s or more.
Further, the melt viscosity η ^* ₁ at 110 ° C. is preferably 5 × 10 ³ Pa · s or less from the viewpoint of suppressing problems such as air entrainment and bump penetration failure due to insufficient fluidity. In the initial stage of the process of joining the semiconductor chip and the circuit board, the resin constituting the insulating film for underfill of the present invention exhibits appropriate fluidity, and there is no gap in the narrow space between the semiconductor chip and the board. It becomes easy to fill, and it is difficult for the resin to be caught between the electrode on the semiconductor chip side and the electrode on the substrate side, and it is easy to ensure good conduction between the two. The melt viscosity η ^* ₁ at 110 ° C. is more preferably 3 × 10 ³ Pa · s or less, further preferably 2 × 10 ³ Pa · s or less, and particularly preferably 1 × 10 ³ Pa · s. s or less.

When the melt viscosity η ^* ₂ at 130 ° C. is 5 × 10 ² Pa · s or more, the resin constituting the NCF is appropriately cured during the temperature rise, so that generation of voids at the time of pressure bonding can be suppressed. . The melt viscosity η ^* ₂ at 130 ° C. is more preferably 1 × 10 ³ Pa · s or more.
Further, by ensuring that the melt viscosity η ^* ₂ at 130 ° C. is 1 × 10 ⁵ Pa · s or less, stable conduction can be ensured at the initial stage of the process of joining the semiconductor chip and the circuit board. Is possible. The melt viscosity η ^* ₂ at 130 ° C. is more preferably 5 × 10 ⁴ Pa · s or less, and further preferably 1 × 10 ⁴ Pa · s or less. This is because if the curing progresses too rapidly, there is a possibility that the bump penetrability is poor and there is a tendency for poor conduction.
The melt viscosities η ^* ₁ and η ^* ₂ at 110 ° C. and 130 ° C., for example, appropriately increase or decrease the content of the filler in the film, the resin for film formation, the curing start temperature of the thermosetting resin, the curing rate, etc. Can be adjusted. The curing start temperature and curing rate of the thermosetting resin can be adjusted by changing the decomposition temperature of the thermal radical generator if it is a thermal radical curing system (when including a thermal radical curable polymerizable substance). If it is an epoxy curing system (when an epoxy resin is included), it can be adjusted by changing the curing agent.

Was measured after holding for one week at 40 ° C., and a melt viscosity eta ^* ₃ at 130 ° C. the eta ^* _{2 and.} Is the ratio η ^* ₃ / η ^* ₂ is that a relationship that it is less than 3, the The storage stability of the underfill insulating film of the invention is good, and it exhibits sufficient fluidity even when stored for a relatively long period of time, such as at room temperature, after the underfill insulating film is attached to a semiconductor wafer. In the process of bonding the semiconductor chip and the circuit board, good bonding can be realized. Also, from the viewpoint of mass production of semiconductor devices, it is desirable that the change in melt viscosity at 130 ° C. of the insulating film for underfill is smaller from the viewpoint of realizing stable bonding. More preferably, the ratio η ^* ₃ / η ^* ₂ is less than ₂ , particularly preferably less than 1.5. Further, the ratio η ^* ₃ / η ^* ₂ is preferably 0.8 or more, and more preferably 1 or more.
The ratio η ^* ₃ / η ^* ₂ of the melt viscosity η ^* ₃ at 130 ° C. and the melt viscosity η ^* ₂ at 130 ° C. measured after holding at 40 ° C. for 1 week is, for example, in a thermal radical curing system Can be adjusted by appropriately increasing or decreasing the content of the polymerization inhibitor in the film.

In the insulating film for underfill of the present invention, the exothermic curve in the range of 50 to 250 ° C. measured by a differential scanning calorimeter preferably has a maximum value in the range of 130 ° C. to 170 ° C. Having the maximum value of the heat generation amount within this range is preferable because it is possible to achieve both suppression of voids and good bonding at a higher level. Further, at least one exothermic peak of the exothermic curve preferably has a half width of 25 ° C. or more, and more preferably has a half width of 30 ° C. or more. Having a half-value width of 25 ° C. or more means that the temperature range where curing occurs has a certain width, and the underfill insulating film does not cure rapidly during heating, and appropriate fluidity over a wide temperature range. It means having. The underfill insulating film having such a form is a so-called easy-to-use underfill insulating film having a wide temperature range in which a process for bonding a semiconductor chip and a substrate can be performed and a high degree of freedom in the process. By using an underfill insulating film with a wide temperature range where the process can be performed in this way, chip size, bump height, bump layout, etc. are different, so even for chips with different flow characteristics required Applicable with wide flexibility.
An insulating film for underfill in which at least one exothermic peak on an exothermic curve in the range of 50 to 250 ° C. measured by a differential scanning calorimeter has a half width of 25 ° C. or more is a plurality of resins having different curing start temperatures For example, it can be realized by using an epoxy resin and (meth) acrylate in combination, or by using different initiators in the same curing system.

In the insulating film for underfill of the present invention, the exothermic curve in the range of 50 to 250 ° C. measured by a differential scanning calorimeter preferably has a maximum value of at least 2. An exothermic curve in the range of 50 to 250 ° C. measured by a differential scanning calorimeter has a maximum value of at least 2 means that the underfill insulating film has appropriate fluidity in a wide temperature range during heating. . The underfill insulating film having such a form is a so-called easy-to-use underfill insulating film having a wide temperature range in which a process for bonding a semiconductor chip and a substrate can be performed and a high degree of freedom in the process. By using an underfill insulating film with a wide temperature range where the process can be performed in this way, chip size, bump height, bump layout, etc. are different, so even for chips with different flow characteristics required Applicable with wide flexibility.
An insulating film for underfill having an exothermic curve in the range of 50 to 250 ° C. measured by a differential scanning calorimeter having at least two peaks is a plurality of resins having different thermal characteristics such as melting point and curing temperature, such as epoxy It can be realized by using a resin and (meth) acrylate together, or by using different initiators in the same curing system.

In the process using the underfill insulating film of the present invention, typically, the soldered electrode formed on the semiconductor chip and the counter electrode formed on the circuit board are in direct contact with each other or bonded to each other, thereby conducting conduction. Secured. In this respect, the insulating film for underfill of the present invention is also used for bonding between a semiconductor chip and a substrate, but a so-called anisotropic conductive film in which conduction between the semiconductor chip and a circuit is obtained through conductive particles. Differentiated from (ACF).
Regarding the characteristics of the resin, since the anisotropic conductive film is usually used when mounting a driver chip of a display, it is required to be cured at a maximum temperature of 200 ° C. or less and about 180 ° C. for a display without heat resistance. . In addition, since the conductive particles are presupposed, the required level for the penetrability of the bumps is low. The inventors found that when the resin prescription used in the anisotropic conductive film is applied to the resin prescription of the insulating film for the under film, it cures quickly, resulting in poor bonding due to poor fluidity during crimping. I found it. Thus, it is difficult to apply the anisotropic conductive film resin formulation directly to the underfilm insulating film.

  The conductive particles contained in the anisotropic conductive film are fine particles having a diameter of several μm to several tens of μm. However, in recent years, with the further miniaturization of semiconductor elements and higher density of mounting, Even if fine conductive particles are used, it is difficult to completely eliminate the risk of an unintended short circuit between electrodes. From this viewpoint, the so-called NCF that does not have conductivity even in the thickness direction is difficult. The underfill insulating film of the present invention corresponding to the above is an underfill film suitable for mounting at a high density of a semiconductor element that is miniaturized as compared with an anisotropic conductive film, and its superiority will become more prominent in the future. It is expected to become something.

In the insulating film for underfill of the present invention, as described above, in order to prevent an unintended short circuit between electrodes, it is preferable that the insulating film does not have conductivity even in the thickness direction. From the viewpoint of preventing short circuit, it is desirable that the insulating film for underfill of the present invention has a low content of conductive particles or substantially does not contain conductive particles, unless there is a technical requirement. . That is, the content of the conductive particles in the insulating film for underfill of the present invention is preferably 5% by mass or less, and particularly preferably 2% by mass or less.
From the viewpoint of short circuit prevention, it is desirable that the underfill insulating film of the present invention has a low metal content or substantially no metal unless there is a technical need. That is, the metal content of the insulating film for underfill of the present invention is preferably 5% by mass or less, and particularly preferably 2% by mass or less.

The insulating film for underfill of the present invention is only required to satisfy the above-mentioned conditions for the melt viscosity η ^* ₁ , η ^* ₂ , and η ^* _{3 at} a specific temperature and thermal history, and the relationship between them. There is no particular limitation on the type and content of the constituent material, but it is preferable to include a polymer resin for film formation, and it is designed for realizing desired curing characteristics including the melt viscosity. From the viewpoint of flexibility and the like, it is more preferable to include a combination of a plurality of thermosetting resins.

(Resin for film formation)
As the resin for film formation, for example, phenoxy resin, polyimide resin, polyamideimide resin, polyamide resin, and acrylic resin are preferable. From the viewpoint of the glass transition point after curing, a phenoxy resin, a polyimide resin, and a polyamideimide resin are more preferable, and a resin that can be dissolved in an organic solvent is preferable from the viewpoint of film production. Preferred solvents are preferably soluble in ethyl acetate, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, dimethylacetamide (DMAC), and N-methyl-2-pyrrolidone (NMP) at low temperatures. It is more preferable that it can be dissolved in a solvent having a boiling point of 150 ° C. or lower from the viewpoint of drying.
As the resin for film formation, one kind may be used alone, or two or more kinds may be used in combination.
Moreover, if the resin for film formation is modified with a functional group that reacts with a thermosetting resin described later, physical properties after curing, such as Tg and thermal expansion coefficient, are improved. On the other hand, since it is necessary to maintain the latent curability before pressure bonding, it is often better to avoid functional groups with high activity.
It is preferable that the compatibility with the thermosetting resin described later is high. This is because if the NCF resin is phase-separated and becomes turbid, the mark visibility on the chip surface deteriorates when it is applied to the bump surface.
Further, as the physical properties after curing of the mounting material, it is required that the glass transition point is high and the coefficient of thermal expansion is low as in the case of the liquid underfill. From such a viewpoint, the following resins are more preferable.

(Phenoxy resin)
As the resin for film formation, a phenoxy resin is particularly preferable from the viewpoint of glass transition point such as solvent solubility, compatibility with thermosetting resin, film forming ability, insulation, and the like.
Preferred phenoxy resins include bisphenol skeleton (bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, etc.), novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, Examples include, but are not limited to, phenoxy resins having one or more skeletons selected from the group consisting of an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton.

  Among these, in the present invention, a phenoxy resin having one or more skeletons selected from the group consisting of a bisphenol skeleton, a biphenyl skeleton, and a fluorene skeleton is preferable, and a group consisting of a bisphenol A skeleton, a bisphenol F skeleton, a biphenyl skeleton, and a fluorene skeleton. A phenoxy resin having one or more skeletons selected from is more preferable.

Especially, the phenoxy resin which has a structure represented by the following general formula (P1) is preferable.

Here, Rx and Ry each independently represents a hydrogen atom or a glycidyl group. L represents a single bond, or —C (Ra) (Rb) —, —O—, —S— or —SO ₂ —. Here, Ra and Rb each independently represent a hydrogen atom or an alkyl group.
R ¹ represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. The alkyl group for R ¹ preferably has 1 to 10 carbon atoms, more preferably 1 to 4, and most preferably 1. Examples include methyl, ethyl, isopropyl, t-butyl, t-pentyl, 2-ethylhexyl, t-octyl, and n-nonyl. Alkoxy group in R ¹ is preferably 1 to 10 carbon atoms, more preferably 1 to 4, 1 being the most preferred. Examples include methoxy, ethoxy, isopropoxy, n-butoxy, 2-ethylhexyloxy, n-octyloxy, and n-nonyloxy. Examples of the halogen atom in R ¹ include a fluorine atom, a chlorine atom, and a bromine atom. R ¹ is particularly preferably a hydrogen atom.
m1 is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.

  As the phenoxy resin having a fluorene skeleton, a phenoxy resin obtained by a reaction of 9,9-bis (4-hydroxyphenyl) fluorene with diglycidyl ether of bisphenol and / or diglycidyl ether of biphenol is preferable. Among them, a phenoxy resin obtained by reaction of biphenol with diglycidyl ether is preferable, and a phenoxy resin obtained by reaction with 2,2 ′, 6,6′-tetramethyl-4,4′-biphenol diglycidyl ether is preferable. Particularly preferred.

  The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or a glycidyl group, but a glycidyl group is preferred from the viewpoint of reactivity with other components. A phenoxy resin may be used alone or in combination of two or more.

  Examples of commercially available phenoxy resins include, for example, trade names of Toto Kasei Co., Ltd., FX280, FX293, FX293S (fluorene skeleton-containing phenoxy resin), trade names of Mitsubishi Chemical Corporation, jER 1256, jER 4250, Trade name, YP-50, YP-50S (all bisphenol A skeleton-containing phenoxy resin) manufactured by Nippon Steel Chemical Co., Ltd., trade name, YX8100 (bisphenol S skeleton-containing phenoxy resin) manufactured by Mitsubishi Chemical Corporation Trade name, YX6954 (bisphenol acetophenone skeleton-containing phenoxy resin) manufactured by Mitsubishi Chemical Corporation, trade names of YX7200, YL7553, YL6794, YL7213, YL7290, YL7482 and the like.

In the present invention, the molecular weight of the phenoxy resin that can be preferably used as the resin for film formation is not particularly limited, but from the viewpoint of film forming ability, a phenoxy resin having a number average molecular weight exceeding 5000 in terms of polystyrene may be used. preferable. The number average molecular weight of the phenoxy resin is more preferably 7000 or more, and particularly preferably 9000 or more. On the other hand, the upper limit of the number average molecular weight of the phenoxy resin is not particularly limited, but is preferably 15000 or less and more preferably 12000 or less. When the number average molecular weight is 15000 or less, solubility in an organic solvent is improved, and productivity can be improved.
The epoxy equivalent of the phenoxy resin is preferably in the range of 3000 to 20000, more preferably 5000 to 10,000.
Moreover, it is preferable that the glass transition temperature measured with a differential scanning calorimeter is 80 degreeC or more, More preferably, 130 degreeC or more is preferable. When the glass transition temperature is within this range, the glass transition temperature of the entire cured insulating film for underfilm is increased, and the reliability of the mounted product is improved. There is no particular upper limit to the glass transition temperature, but a temperature of 250 ° C. or lower is preferable from the viewpoint of solvent solubility.

  In the present invention, when the phenoxy resin is used as the film forming resin, the content of the phenoxy resin is not particularly limited, but 10 parts by mass of the total of 100 parts by mass of the film forming resin and the thermosetting resin. It is above, Preferably it is 20 mass parts or more, More preferably, it is 25 mass parts or more. When the amount is 10 parts by mass or more, an appropriate strength is easily developed when a film is produced or used in an uncured stage. On the other hand, the content of the phenoxy resin is usually 50 parts by mass or less, preferably 40 parts by mass or less. When it is 50 parts by mass or less, problems such as poor fluidity and insufficient curing due to thermosetting resin can be effectively suppressed.

(Polyimide resin)
A solvent-soluble polyimide that is polymerized by dehydration condensation of a commercially available tetracarboxylic acid and diamine in a solvent is also suitable as a film-forming polymer preferably used in the present invention. A solvent-soluble polyimide can be polymerized with a combination of known monomers.
As the reaction point with the thermosetting resin, those having a reactive group in the side chain are more preferable in terms of increasing the Tg after curing and decreasing the thermal expansion coefficient. A Tg of about 50 to 200 ° C. is preferable for the development of melting characteristics when combined with a thermosetting resin.
The polyamideimide resin can also be applied to the present invention with the same index as the polyimide resin.

(Thermosetting resin)
The insulating film for underfill of the present invention is solid at room temperature from the viewpoint of realizing the specific melt viscosity η ^* ₁ , η ^* ₂ , and η ^* ₃ and the specific relationship between them at the above specific temperature and conditions. It is in the form of a film, and once melted by heating, the viscosity decreases and can be bonded, and the bump can be penetrated. By further heating, the viscosity increases to increase the viscosity, so that voids can be suppressed. It is done. For this purpose, it is preferable to add a thermosetting resin to the film-forming resin.
Examples of thermosetting resins include epoxy resins, thermal radical polymerizable substances, urethane resins, thermosetting polyamide resins, etc., but there are potentials such as the cure start temperature, the degree of freedom in the design of the curing speed characteristics, etc. In view of the above, a system in which a thermal radical polymerizable substance and a thermal radical generator are combined is preferable, and an epoxy resin added is particularly preferable on the adhesive surface to the adherend.

(Epoxy resin)
The insulating film for underfill of the present invention desirably contains an epoxy resin from the viewpoint of imparting adhesion to the adherend.
Examples of the epoxy resin include bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type, cresol novolac type. Type, trishydroxyphenylmethane type, tetraphenylolethane type and other bifunctional epoxy resins and polyfunctional epoxy resins, or hydantoin type, trisglycidyl isocyanurate type or glycidylamine type epoxy resins can be used. It is not limited to. Epoxy resins can be used alone or in combination of two or more. From the viewpoint of alignment mark visibility, those that are compatible with the resin for film formation and other thermosetting resins and that do not phase separate with them are preferred.
From the viewpoint of reducing stickiness at room temperature, a solid epoxy resin is preferable, and from the viewpoint of improving the glass transition point and the elastic modulus after curing, a bifunctional or higher polyfunctional epoxy resin is more preferable. For these reasons, a cresol novolac type epoxy resin can be particularly preferably used.

The cresol novolak type epoxy resin may be any of an o-cresol novolak type epoxy resin, an m-cresol novolak type epoxy resin, and a p-cresol novolak type epoxy resin, and in particular, an o- represented by the following formula: Cresol novolac type epoxy resins are preferred. The glycidyl groups in these resins are preferably those obtained by substituting the phenolic hydroxyl groups in the corresponding cresol novolak resins with glycidoxy groups.
The molecular weight of the cresol novolac type epoxy resin is preferably 800 to 1300, more preferably 900 to 1300. As a softening point, 60 degreeC or more is preferable, More preferably, 80 degreeC or more is preferable.

  In the present invention, when an epoxy resin is used as the resin for imparting adhesion and adjusting the curing rate, the content of the epoxy resin is not particularly limited, but the total of 100 parts by mass of the resin for film formation and the thermosetting resin. The amount is usually 10 parts by mass or more, preferably 15 parts by mass or more, and more preferably 20 parts by mass or more. Since it is 10 mass parts or more, the adhesiveness of the whole film and a cure rate can be controlled appropriately. On the other hand, the content of the epoxy resin is usually 50 parts by mass or less, preferably 30 parts by mass or less. Since it is 50 mass parts or less, the disadvantageous influence on film formation can be suppressed and the compounding quantity of the radical curing system for void suppression can also be ensured.

(Thermal radical polymerizable substance)
The underfill insulating film of the present invention preferably contains a thermal radical polymerizable substance for the purpose of suppressing voids during curing. A thermal radical reaction system is excellent for developing rapid curability in a temperature range that has potential and suppresses voids in NCF applications.
Here, the thermal radical polymerizable substance is a substance having a functional group that is polymerized by a thermal radical, and examples thereof include (meth) acrylates and maleimide compounds. The thermal radical polymerizable substance can be used in a monomer or oligomer state, and the monomer and oligomer can be used in combination.
As the thermal radical polymerizable substance, (meth) acrylate is particularly preferable. As the (meth) acrylate, monofunctional (meth) acrylate or bifunctional or higher (meth) acrylate can be used. Examples of the monofunctional (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, and n-butyl (meth) acrylate. Bifunctional or higher (meth) acrylates include bisphenol F-EO modified di (meth) acrylate, bisphenol A-EO modified di (meth) acrylate, bisphenol F epoxy (meth) acrylate, bisphenol A epoxy (meth) acrylate, tri Examples include methylolpropane tri (meth) acrylate, trimethylolpropane EO-modified tri (meth) acrylate, and polyfunctional urethane (meth) acrylate. These thermal radical polymerizable substances may be used alone or in combination of two or more.
Among these, a bifunctional (meth) acrylate is preferably used because of easy control of the characteristics during curing. Among these, epoxy (meth) acrylate and the like are particularly preferably used from the viewpoints of compatibility and heat resistance.
In order to introduce a crosslinked structure, it is also preferable to use a polyfunctional (meth) acrylate in combination. As the polyfunctional (meth) acrylate, trimethylolpropane tri (meth) acrylate and the like are particularly preferably used.

Although there is no restriction | limiting in particular in content of a heat | fever radically polymerizable substance, Usually, it is 30 mass parts or more in the total of 100 mass parts of resin for film formation, and a thermosetting resin, Preferably it is 40 mass parts or more. . Since it is 30 mass parts or more, the suppression of the void at the time of hardening, etc. becomes easy. On the other hand, the content of the thermal radical polymerizable substance is usually 70 parts by mass or less, preferably 60 parts by mass or less. When the amount is 70 parts by mass or less, stickiness of the underfill insulating film can be suppressed. When the stickiness is small, handling of wafers and chips with NCF becomes easier. The conveyance trouble which sticks to the jigs which contact an NCF surface can also be controlled. Garbage can also be suppressed.
Moreover, in order not to deteriorate the visibility when pasted on a chip, it is preferable to select a structure that does not phase separate from other resins.

(Epoxy curing agent)
In the present invention, when an epoxy resin is used as a resin for imparting adhesion and adjusting the curing rate, it is preferable to use an epoxy curing agent as appropriate. In this application, since latency, migration resistance, and an appropriate curing speed are required, it is desirable to appropriately select an applicable curing agent. Among these, the rapid curing necessary for void suppression can be carried out by the thermal radical curing system, so that the latent curing is particularly important. That is, it is preferable to use a latent curing agent.
Among known curing agents, both amine-based and acid anhydride-based latents are not always sufficient, and it is preferable to select one that meets this purpose to some extent from phenol curing and imidazole curing.
Among these, a solid and good latent imidazole curing agent can be preferably used. More specifically, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′ )]-Ethyl-s-triazine isocyanuric acid adduct and the like can be used particularly preferably.

  The content of the epoxy curing agent is preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass with respect to 100 parts by mass in total of the resin for film formation and the thermosetting resin. . By being 0.1 mass part or more, the hardening time by heat processing becomes short and it becomes easy to improve productivity. Moreover, it becomes easy to ensure long-term storage stability because content of an epoxy hardening | curing agent is 10 mass parts or less, and it is preferable also from a viewpoint of the outgas suppression at the time of pressure bonding.

(Thermal radical generator)
When the insulating film for underfill of the present invention contains a thermal radical polymerizable substance such as an acrylic compound, a thermal radical generator such as an organic peroxide or an azo compound is added to accelerate the polymerization of the thermal radical polymerizable substance. It is preferable to use together.
As the organic peroxide, for example, peroxyesters, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates and the like can be preferably used. These organic peroxides may be used alone or in combination of two or more.
Among these thermal radical generators, those having a one-minute half-life temperature of 140 ° C. or higher are preferable, and more preferably 160 ° C. or higher. When the half-life temperature for 1 minute is 140 ° C. or higher, the resin fluidity at the time of pressure bonding is appropriate, so that the resin engagement between the electrodes between the chip and the substrate (curing proceeds before the electrodes come into contact with each other) It is preferably used from the viewpoint of suppressing the phenomenon that the resin bites in between. On the other hand, the one-minute half-life temperature is preferably 200 ° C. or lower, more preferably 190 ° C. or lower. When the 1-minute half-life temperature is 200 ° C. or lower, curing at the time of pressure bonding is appropriate, and the effect of suppressing voids is high.
Furthermore, the molecular weight of the thermal radical generator is preferably 200 or more, more preferably 250 or more, from the viewpoint of suppressing peroxide volatilization in the solvent drying step during film production.
Among these, 2,2-di (4,4-di- (t-butylperoxy) cyclohexyl) propane (manufactured by NOF Corporation, Pertetra A), n-butyl-4,4-di (t- Butyl peroxy) valerate (manufactured by NOF Corporation, Perhexa V), 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane (manufactured by NOF Corporation, Perhexa 25B), 2,5- Dimethyl-2,5-di (t-butylperoxy) -3-hexyne (manufactured by NOF Corporation, perhexine 25B) is preferably used.
Although there is no restriction | limiting in particular in the addition amount of thermal radical generators, such as an organic peroxide, Usually, 0.1-5 mass parts is added with respect to a total of 100 mass parts of resin for film formation, and a thermosetting resin. It is particularly preferable to add 0.3 to 3 parts by mass. Since it is 0.1 parts by mass or more, curing of acrylate or the like is sufficient, and since it is 5 parts by mass or less, the storage stability of the underfill insulating film is good, and outgassing at the time of pressure bonding is suppressed. Therefore, it is also preferable from the viewpoint of void suppression.

(Polymerization inhibitor)
The insulating film for underfill of the present invention preferably contains a polymerization inhibitor in addition to the thermal radical polymerizable substance and the thermal radical generator. By containing a polymerization inhibitor, unnecessary polymerization of the thermal radical polymerizable substance during storage can be suppressed, so that the storage stability is improved, for example, at 130 ° C. after being held at 40 ° C. for 1 week. It becomes easier to realize the characteristic that the ratio η ^* ₃ / η ^* _{2 of the} melt viscosity η ^* ₃ to the melt viscosity η ^* ₂ at 130 ° C. is less than 3.
The content (mass) of the polymerization inhibitor is preferably 600 to 10000 ppm, more preferably 800 to 5000 ppm with respect to the amount (mass) of the thermal radical polymerizable substance. Since the content of the polymerization inhibitor is 600 ppm or more, it is easy to realize sufficient storage stability, and since it is 100000 ppm or less, it does not unnecessarily inhibit the polymerization of the thermal radical polymerizable substance at the time of curing, Voids and the like can be effectively suppressed. In particular, when NCF is attached to a semiconductor wafer, the chip with NCF is FC-connected after dicing and pick-up processes. It may take time from wafer lamination to flip chip connection, and particularly high storage stability is required. For this reason, it is preferable to contain a polymerization inhibitor in said range.

There is no restriction | limiting in particular in the kind of polymerization inhibitor, A suitable polymerization inhibitor can be used suitably in relation to the kind of thermal radically polymerizable substance, a polymerization mechanism, etc. For example, quinones such as hydroquinone, methyl ether hydroquinone, p-benzoquinone, t-butylparabenzoquinone, 2,5-dichloro-p-benzoquinone, 2,6-dichloro-p-benzoquinone, tetrachloro-p-benzoquinone; -Nitro compounds such as dinitrobenzene, m-dinitrobenzene, 2,4-dinitrotoluene, 1,3,5-trinitrobenzene, 1,3,5-trinitrotoluene; o-nitrophenol, m-nitrophenol, p- Nitrophenols such as nitrophenol, 2,4-dinitrophenol and 2,4,6-trinitrophenol; nitroso and nitrone compounds such as methyl-α-nitrosoisopropylketone and phenyl-t-butylnitrone; iron chloride (III ) And other metal salts, phenothiazine, etc. Although it is Rukoto, but are not limited to.
Among these, quinones are preferably used from the viewpoint that the effect of inhibiting polymerization can be effectively exhibited even in the step of attaching NCF to the bump forming surface of the wafer, and p-benzoquinone (also referred to as PBQ), methyl-p-benzoquinone. T-butylparabenzoquinone (also referred to as TBQ) and 2,5-diphenyl-p-benzoquinone are particularly preferable.

(Flux agent)
Further, in addition to / in place of the epoxy curing agent, an acid (anhydride) having a flux function may be used. In addition to being able to cure the epoxy resin, such an acid (anhydride) has a flux function so that the oxide film on the solder surface and the electrode surface can be removed. It is preferable because the electrical connection between them can be made easier and more reliable.
Examples of the acid (anhydride) having a flux function include aliphatic dicarboxylic acids such as adipic acid, aliphatic propylene anhydrides such as tetrapropenyl succinic anhydride and dodecenyl succinic anhydride, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. Examples thereof include alicyclic acid anhydrides such as acids, aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride. These acids (anhydrides) having a flux function may be used alone or in combination of two or more. If these fluxes can be dispersed in solid form in NCF, the potential becomes advantageous in terms of reaction with the epoxy resin. In order to disperse in a solid form, those having poor solubility in a solvent used in a compounding liquid described later are preferable. It is advisable to pulverize and mix to a sufficiently small size with respect to the NCF film thickness. On the other hand, it is preferable that the melting point is reached at a temperature lower than the solder melting temperature to exhibit flux activity. Among these acids (anhydrides), succinic acid, adipic acid and the like are particularly preferable in view of the above characteristics, solder connectivity, epoxy curing action, industrial availability, and the like.

  The blending amount of the acid (anhydride) having a flux function is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 100 parts by mass in total of the resin for film formation and the thermosetting resin. Is 0.5 parts by mass or more and 3 parts by mass or less. When the blending amount of the acid (anhydride) having a flux function is 0.1 parts by mass or more, solder wetting can be promoted and electrical connection between the semiconductor chip and the substrate can be effectively promoted. If the compounding quantity of the acid (anhydride) which has a flux function is 10 mass parts or less, it is preferable from a viewpoint of ensuring storage stability and suppressing outgas at the time of a compression test.

(Filler)
By adding a filler, the thermal expansion coefficient of the underfill insulating film is reduced, the dimensional stability is improved, the thermal stress on the chip and the substrate is reduced, and the reliability is also improved. On the other hand, as the filling amount increases, the flow characteristics deteriorate. In terms of the visibility of the mark, in the case of a filler having a refractive index difference from that of the resin, if the size is larger from the vicinity of the wavelength of light, scattering occurs and the visibility is deteriorated. Further, if a filler having a larger size is interposed in the chip / substrate gap, it causes a defect such as chip crack. If a large filler bites between the bump and the electrode, conduction failure occurs.
As long as the inorganic filler satisfies the above conditions, silica (fused silica, crystalline silica, fumed silica, etc.), alumina, aluminum nitride, silicon nitride, boron nitride powder, etc. may be used. From the viewpoint of fluidity, fumed silica or fused silica is particularly preferable.

The average particle diameter of the inorganic filler is preferably 0.01 μm or more. When it is 0.01 μm or more, an increase in melt viscosity due to the interaction between the filler and the resin can be suppressed. The average particle diameter of the inorganic filler is preferably 3 μm or less, more preferably 1 μm or less, from the viewpoint of suppressing filler biting between the semiconductor element and the electrode of the substrate and the transparency of the underfill insulating film. More preferably, it is 0.1 μm or less. The average particle diameter can be determined by observation with a photometric particle size distribution meter (for example, HORIBA, apparatus name: LA-910) or a microscope. However, in these fine powders, the secondary particle size is measured unless the dispersion treatment is carried out satisfactorily.
The particle size of the filler is preferably top-cut by classification operation, and it is preferable to cut coarse particles with a filter in the course of blending, dispersing, and coating.

  The content of the inorganic filler in the underfill insulating film is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 15% by mass or more. When it is 5% by mass or more, the coefficient of thermal expansion after curing becomes better than that of no addition. The content of the inorganic filler in the underfill insulating film is preferably 60% by mass or less, more preferably 40% by mass or less. When it is 60% by mass or less, fluidity can be ensured, good transparency can be obtained, and biting of the filler can be satisfactorily suppressed when the semiconductor chip is mounted on the substrate via NCF.

(Other additives)
The insulating film for underfill of the present invention can be appropriately mixed with components other than those described above as long as the object of the present invention is not adversely affected. Examples of other components include a flame retardant, a silane coupling agent, an ion trap agent, and an organic filler.
Examples of the flame retardant include, but are not limited to, phosphorus compounds, metal hydroxides, antimony trioxide, antimony pentoxide, brominated epoxy resins, and the like.
By adding the silane coupling agent, it is possible to improve the adhesion between the filler and the resin interface, the semiconductor chip used in the process, the circuit board, etc. and the insulating film for underfill. Examples of silane coupling agents include epoxy groups such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane. And those having a reactive double bond can be used, but are not limited thereto.
By adding an ion trapping agent, it is possible to capture ionic impurities such as cations and anions generated from other materials that make up the insulating film for electrode wiring and underfill, and prevent migration and corrosion of the wiring. it can. Examples of ion trapping agents that can be used include hydrotalcites, bismuth hydroxide, and chelates, but are not limited thereto.

(Manufacturing method of insulating film for underfill)
The insulating film for underfill of this invention is produced as follows, for example. First, the above-mentioned components, which are materials for forming an underfill insulating film, are blended and dissolved or dispersed in a solvent (for example, methyl ethyl ketone, ethyl acetate, toluene, etc.) to prepare a coating solution. When the filler is dispersed, the filler is dispersed using a dispersing device such as a bead mill as necessary. Next, after applying the prepared coating liquid to a predetermined thickness on a substrate separator with a general-purpose coater, the solvent is dried using a heat oven or the like to form an underfill insulating film. As the drying condition, if the residual solvent is extremely left, it becomes a cause of generation of voids at the time of FC connection. Therefore, it is preferable to adjust the drying condition to at least 1% or less. The drying temperature and drying time are preferably adjusted to such an extent that the curing reaction does not significantly start in the drying process. It is recommended to adjust the temperature at 100 ° C for several minutes.
Since there is a limit to the thickness that can be applied under the above conditions, when an excessively thick NCF is required, a predetermined thickness can be obtained by stacking a plurality of NCFs having a thickness that satisfies the residual solvent condition.
The base separator is preferably, for example, a PET (polyethylene terephthalate), OPP (stretched polypropylene), CPP, poly-4-methylpentene-1, PTFE, or the like with a release agent such as silicone applied as necessary. Can be used.
In consideration of adhesion of foreign matters, it is better not to handle NCF barely. In such a surface, after drying with the above-mentioned coater, the slightly adhesive film may be laminated on the NCF surface, or the separator may be laminated by heating. If a difference is provided in the ease of peeling of the easily peelable material on both sides of the NCF, the subsequent handling of the NCF becomes easy. By separating the easily peelable material on the side that can be lightly peeled first, NCF can be stably left on the heavily peelable easily peelable material.

The thickness of the underfill insulating film of the present invention is not particularly limited, and may be set as appropriate in consideration of the gap between the semiconductor chip and the circuit board and the height of connection members such as electrodes and solder. Assuming the current normal process, a thickness of about 1 to 250 μm is preferable, and a thickness of about 5 to 25 μm is more preferable. In the case of flip-chip connection between silicon materials, since the thermal stress is small, the necessity of making a gap large is small, and it is assumed that the gap will become small in the future. On the other hand, when the resin substrate and the chip are connected, the bump height is increased so that the thermal stress can be reduced according to the chip size and the resin substrate material characteristics. It is preferable to prepare NCF thickness corresponding to each.
In the space under the chip filled with NCF, there is a volume of protrusions such as bumps, and there is an appropriate gap in which the bumps are appropriately crushed. In order to form such an appropriate gap, subtract the bump volume from the volume calculated by the product of the gap and the chip area, and divide the volume by the chip area by adding the volume of good protrusion formation. An appropriate NCF thickness can be approximated. Since the fluidity of the NCF varies depending on the bump layout, it is more preferable to test with an actual chip.

(Product form of NCF)
The underfill insulating film of the present invention is preferably protected by a releasable film. The release film has a function as a protective material for protecting the insulating film for underfill until it is subjected to an actual process. The release film is peeled off when, for example, a semiconductor element is stuck on an underfill insulating film. As the release film, an easily peelable film such as a separator or a slightly adhesive film used in the above manufacturing process may be used as it is.
NCF may be laminated with a back grind (BG) tape. As a method of using NCF, as an adhesive tape for circuit surface protection during back grinding (BG), it is used with an easily peelable film / NCF configuration and attached to the bump surface of the wafer, and after peeling off the easily peelable film layer, NCF And a method of obtaining a chip with NCF by dicing the wafer. The NCF of the present invention may be used in such a form.
Further, NCF may be laminated with a dicing (DC) tape. As a method of using NCF, a method of using a dicing tape and NCF integrally is also disclosed, and the NCF of the present invention may be used in such a form.

(Method for manufacturing semiconductor device)
Using the insulating film for underfill of the present invention, for example, by filling a space between the semiconductor chip and the circuit board, a soldered electrode formed on the semiconductor chip, and a counter electrode provided on the circuit board, Can be protected.
As a solder material, a tin-lead metal material, a tin-silver metal material, a tin-silver-copper metal material, a tin-zinc metal material, a tin-zinc-bismuth metal material, or the like is preferably used. it can. It also includes a structure in which the solder is formed at the tip of the copper pillar. The material of the electrode and the counter electrode is not particularly limited as long as it is conductive, and examples thereof include gold / nickel and copper.

As one embodiment of the present invention, a semiconductor chip on which a soldered electrode is formed and a circuit board on which a counter electrode facing the soldered electrode is formed according to any one of [1] to [9] A method for manufacturing a semiconductor device, which is bonded through an underfill insulating film,
a) a step of attaching the insulating film for underfill on a wafer having a soldered electrode under vacuum;
b) dividing the wafer into individual semiconductor chips with an insulating film for underfill;
c) With the semiconductor chip and the circuit board, the electrode of the semiconductor chip and the counter electrode of the circuit board are respectively substantially abbreviated in a temperature condition where the maximum temperature is equal to or higher than the melting point temperature of the solder mounted on the chip. A method of manufacturing the semiconductor device, which includes a thermocompression bonding step of thermocompression bonding so as to be in contact with the center line.

At this time, the wafer after performing step a) (and step b) if necessary is stored at room temperature as it is because of the switching of brands and the schedule of the manufacturing apparatus, etc. May be provided. The insulating film for underfill of the present invention has a melt viscosity η ^* _{2 at} 130 ° C. and a melt viscosity η ^* ₃ at 130 ° C. measured after holding at 40 ° C. for 1 week, and the ratio η ^* ₃ / η ^*. By having a relationship in which ₂ is less than 3, good connection and productivity can be realized.

  In the above-described embodiment, plasticity and fluidity are exhibited in the early stage of the process of joining the semiconductor chip and the substrate, and the curing proceeds sufficiently in the later stage of the process, and further excellent in long-term storage stability. Since the insulating film for underfill according to the present invention is used, the conduction between the soldered electrode formed on the semiconductor chip and the counter electrode provided on the circuit board is ensured, and the semiconductor chip and the circuit board It is possible to fill the space between and without voids, and to provide high reliability of the semiconductor chip mounted on the circuit board after curing.

Hereinafter, step c) will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing a semiconductor chip (1), a circuit board (5), and an underfill insulating film (4) of the present invention before step c). The semiconductor chip (1) has an integrated circuit formed on a semiconductor surface such as silicon and has soldered electrodes for connection called bumps. The soldered electrode is obtained by forming a solder (3) on an electrode (2a) made of copper or the like via a diffusion preventing metal film of a bump material.
These solder surfaces oxidize over time. If the oxide film is removed by plasma treatment or the like before attaching NCF, more stable bonding can be obtained.

  The circuit substrate (5) has a circuit formed on a base material such as a rigid substrate, a flexible substrate, a silicon substrate, a glass substrate, or the like. In addition, a counter electrode (2b) having a predetermined thickness is formed at a position facing the soldered electrode of the semiconductor wafer (1) on the mounting portion on which the semiconductor wafer (1) is mounted.

Here, the underfill insulating film (4) is attached to the bumped semiconductor wafer (1) in step a) (not shown). Affixing is performed at a temperature of 60 to 120 ° C. under a vacuum, for example. The insulating film for underfill (4) exhibits fluidity, fills the unevenness caused by the electrodes (2a) and the solder (3) formed on the semiconductor wafer (1), and is in close contact with the semiconductor wafer (1). Usually, the thickness of the underfill insulating film (4) is set so that the electrode (2a) and the solder (3) do not penetrate the underfill insulating film (4).
Subsequently, the wafer with the underfill insulating film is singulated to produce individual chips with the underfilm (step b)).

Next, in step c) of the present embodiment, the semiconductor chip on which the underfill insulating film (4) is attached is mounted on the circuit board (5) (FIG. 2). At this time, the plurality of electrodes (2a) and the plurality of counter electrodes (2b) are aligned so as to be in contact with each other on a substantially center line. The alignment is performed by using a flip chip bonder to recognize a mark formed near the chip mounting portion of the substrate and a mark formed on the chip surface with a camera. At this time, if the mark edge cannot be clearly identified through the NCF, the mounting position accuracy deteriorates. Also on the device side, we will make it easy to recognize the mark edge with coaxial / diffuse lighting.
The load applied in step c) is preferably in the range of 5 to 500N, more preferably in the range of 10 to 50N. Appropriate upper limits for weighting are to ensure that the chip does not break, and that the solder does not collapse too much. If the load is too small, bumps may not be in sufficient contact, bubbles may not be able to escape. It is preferable to look for good conditions while observing this area.

Further, the temperature applied in step c) is set to about 80 ° C. to 150 ° C. in a general setting where a ceramic heater is provided on the head side (upper part) and a constant heater is provided on the stage side. In the case of a resin substrate, warpage occurs, and therefore, about 60 to 100 ° C. is preferable. In the case where a silicon chip or silicon wafer is placed on the stage, the head material escapes to the stage side because the substrate material has good heat transfer, and the actual temperature of the chip is significantly lower than the head setting, so the stage temperature is increased. It is good to set to.
The NCF-attached chip is held on the head side, but this temperature is a temperature at which the underfill insulating film has fluidity at the initial stage of applying the load, but does not significantly harden, for example, from 60 ° C. to 150 ° C. The temperature is preferably in the range of 80 ° C., more preferably in the range of 80 ° C. to 130 ° C., particularly preferably around 100 ° C., and when the bumps are brought into contact with the electrodes before the temperature rises to the solder melting temperature, poor conduction is unlikely to occur. . The time for which sufficient bump contact can be realized on the entire surface of the chip varies depending on the chip size and the bump layout. Therefore, it is preferable to adjust the time within a range of several seconds. After this step, the temperature can be raised to the solder melting temperature with the maximum capacity of the ceramic heater (generally several tens of degrees centigrade / s) in consideration of the tact time. There is often a discrepancy between the set temperature of the head and the actual bump temperature due to the heat escape to the stage. It is preferable to check the correspondence between the set temperatures.
The duration at the solder melting temperature is preferably in the range of 0.1 second to 20 seconds, more preferably in the range of 0.5 second to 5 seconds, from the viewpoint of reliably joining the electrodes. If necessary, the semiconductor device may be released from the solder melting temperature before being released. Further, the duration of heat and pressure in step c) is preferably in the range of 30 seconds, and more preferably in the range of 1 to 20 seconds, from the viewpoint of productivity.

On the other hand, the above-mentioned cost problem in flip chip connection has a problem of poor productivity in an expensive flip chip bonder with good positional accuracy. If a series of operations such as chip picking, substrate setting, alignment, contact, heating, cooling, etc. take time, the cost increases. For this reason, for example, when stacking chips on a chip, in order to save the time for replacing the substrate (chip), by setting a wafer, which is an assembly of chips, as a substrate (chip-on-wafer bonding), tact It has become common to reduce time.
In addition, since it takes time to heat up and cool down, for example, with regard to the above-mentioned temperature rising / cooling operation, precise positioning and temporary bonding are performed with an expensive flip chip bonder, A method of carrying out the operation of raising the temperature to the solder melting temperature by heating a plurality of chips collectively with a cheaper crimping apparatus that does not require advanced position control is also being studied. The insulating film for underfill of the present invention can also be applied to such a crimping operation. Temporary bonding conditions in this case are set to the upper limit of about 150 to 200 ° C. in the above operation to achieve a certain level of bump contact and curing of the underfill insulating film, while raising the temperature to a temperature higher than that. By eliminating temperature and cooling, the tact time can be reduced.

  The semiconductor chip (1) on which the solder (3) -attached electrode (2a) is formed by the above-described process, the underfill insulating film (4) of the present invention, and the counter electrode (2b) facing the solder-attached electrode And a circuit board (5) on which the electrodes are formed are joined in this order, and at least a part, preferably all, of the electrode (2a) with solder (3) is the counter electrode (2b). It is possible to produce a laminate that is in electrical contact with at least some, preferably all of.

In the laminate, the electrode (2a) with solder (3) and the counter electrode (2a) and the counter electrode (2a) are electrically connected to the counter electrode (2b). 2b), it is preferable that there is no underfill insulating film (5), and this ensures a sufficient bonding area between the electrode (2a) with solder (3) and the counter electrode (2b). (The solder is sufficiently wet and a solder joint is formed), and sufficient conduction is obtained.
Moreover, in the said laminated body, a through-hole exists in the insulating film for underfill (5) in the location where the said electrode (2a) with a solder (3) is electrically contacting with the said counter electrode (2b). Preferably, a sufficient bonding area is ensured between the electrode (2a) with solder (3) and the counter electrode (2b) (the solder is sufficiently wetted and solder bonding is formed). ), Sufficient conduction is obtained.

The laminated body is a circuit board on which a semiconductor chip is mounted, and can be used as a semiconductor device through further necessary processes. In the above laminate, the cured underfill insulating film of the present invention fills the space between the semiconductor chip and the circuit board substantially without voids and voids, and has excellent performance as a semiconductor device. It is. That is, by using the underfill insulating film of the present invention, a semiconductor device having excellent performance can be manufactured with high productivity.
Such a semiconductor device can be suitably mounted on an electric / electronic device used for an information processing device, a display, a communication device, a transportation device, and the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this.

In the following examples / comparative examples, physical properties / characteristics were evaluated by the following methods.
(Melt viscosity)
It was determined by measuring the temperature dispersion of melt viscoelasticity using a rheometer (manufactured by Anton Paar, model number: MCR302). The measurement was carried out under the following conditions after using an underfill insulating film laminated to a thickness of 1.0 mm and adhering to a jig at 80 ° C. for 3 minutes in advance.
Environment: Under nitrogen atmosphere Measuring jig: Parallel plate 8mmφ
Deformation mode: shear frequency: 1 Hz
Temperature increase rate: 10 ° C / min Temperature range: 70-200 ° C
(Reaction heat)
Using a differential scanning calorimeter (DSC, manufactured by Perkin Elmer, Diamond DSC), an underfilm insulating film (5 mg) was placed in a pan, and the temperature was increased from −40 ° C. to 250 ° C. at a rate of 10 ° C./min in a nitrogen atmosphere. The exothermic curve was evaluated. The temperature giving the maximum heat generation amount (W / g) was defined as the maximum heat generation temperature. The temperature at which half the maximum heat value was generated was defined as the half-value heat temperature, and the difference between the half-value heat temperatures was defined as the half-value width. Furthermore, when there was a maximum value other than the maximum heat generation amount, it was defined as the other maximum heat generation temperature.
(Crimping test)
Test chip (Global Net Co., Ltd., G03, bump diameter: 20 μm, bump pitch: 40 μm, bump height: 19 μm (copper pillar and tin / silver solder), size: 5 mm × 5 mm, daisy chain structure) Vacuum laminator (Co., Ltd.) with a laminate of underfill insulating film (20 μm) / release PET film (Purex A54, 38 μm manufactured by Teijin DuPont Films Ltd.) so that the underfill insulating film is on the test chip side (Takatori) was laminated under vacuum (vacuum degree: after reaching 13 Pa, pressurization at 80 ° C. for 1 minute). An unnecessary chip peripheral portion was removed from the obtained laminated product with a design knife, and then the release film was removed to obtain a chip with an insulating film for an under film.
Next, using the bonder (Shibuya Kogyo Co., Ltd., DB250), the chip with the insulating film for the under film is properly aligned with the test substrate (Global Net Co., Ltd., G03, silicon substrate). After that, the bonding was performed under the following conditions.
Stage temperature: 100 ° C
Chip temperature: held at 100 ° C. for 1 s, then heated to 260 over 4 s and held for 2 s Load: 45 N (7 s)
The chip temperature was measured by preparing a jig in which a thermocouple was inserted between the chip / substrate separately and crimping under the same conditions.
Voids were evaluated by observing the obtained laminate of the chip / insulating film for underfill / substrate from the chip side with an infrared microscope. The case where no void was generated was indicated by “◯”, and the case where a void was generated was indicated by “X”. In addition, the case where the electrical connection was taken was designated as “J”, and the case where there was a poor conduction was designated as “X”.
(Heat treatment at 40 ° C for 1 week)
The above-mentioned melt viscosity, reaction heat, and insulation film sample for underfill that has not been subjected to the pressure bonding test (initial test) are kept in a constant temperature bath at 40 ° C. for 1 week, and then at 130 ° C. under the same conditions as described above. A melt viscosity test and a pressure bonding test were performed.

[Example 1]
30 parts by mass of phenoxy resin (Mitsubishi Chemical Corporation, 1256B40 (bisphenol A skeleton, number average molecular weight of about 10000, glass transition temperature by DSC 98 ° C., epoxy equivalent 7800)), epoxy resin (DIC Corporation, N-672- EXP (cresol novolac type, softening point 71-79 ° C.), 20 parts by mass of a methyl ethyl ketone solution having a solid content of 70% previously prepared, acrylate (manufactured by Nippon Kayaku Co., Ltd., KAYARAD R-130, bisphenol A epoxy) Mixture of acrylate 55-60%, acrylate monomer 40-45%, average molecular weight (Mw) 500, polymerization inhibitor hydroquinone monomethyl ether (common name: containing 500 ppm) 50 parts by mass, epoxy curing agent (imidazole) (Shikoku Chemicals) Made by Kogyo Co., Ltd. 2 MAOK-PW (2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct)) 3 parts by mass, organic peroxide (manufactured by NOF Corporation) , Perhexa V (n-butyl-4,4-di (t-butylperoxy) valerate), 1 minute half-life temperature 173 ° C., molecular weight 334.46) 0.7 parts by mass, flux (adipic acid) 1 part by mass , 54 parts by mass of silica (manufactured by Denka Co., Ltd., SFP-20M (ultrafine particle spherical type fused silica, d50: 0.3 μm)), a polymerization inhibitor (TBQ (t-butylparabenzoquinone)) as a thermal radical polymerizable substance On the other hand, 800 ppm and methyl ethyl ketone were blended to prepare a resin composition having a solid content concentration of 55%. This was applied to the peeled PET using an applicator and dried in an oven at 90 ° C. for 5 minutes to produce a plurality of underfill insulating films having a thickness of 20 μm.
At least one of the obtained films was evaluated for melt viscosity η ^* ₁ at 110 ° C., melt viscosity η ^* ₂ at 130 ° C., and reaction heat. In addition, the film was subjected to a pressure bonding test to evaluate voids and bonding. The results are shown in Table 1.
Further, at least one other film produced as described above was stored in a constant temperature bath at 40 ° C. for 1 week, and then the melt viscosity η ^* ₃ was evaluated at 130 ° C. Moreover, the pressure bonding test was done using the film and the void and joining were evaluated. The results are shown in Table 1.
[Example 2]
A plurality of insulating films for underfill were produced under the same composition and conditions as in Example 1 except that 4000 ppm of a polymerization inhibitor (t-butylparabenzoquinone) was added to the thermal radical polymerizable substance. Immediately and after the film was stored at 40 ° C. for 1 week, the characteristics were evaluated. The results are shown in Table 1.
[Example 3]
A plurality of underfill insulating films were produced under the same composition and conditions as in Example 1 except that 8000 ppm of a polymerization inhibitor (t-butylparabenzoquinone) was added to the thermal radical polymerizable substance. Immediately and after the film was stored at 40 ° C. for 1 week, the characteristics were evaluated. The results are shown in Table 1.
[Example 4]
The same as Example 1 except that the blending amount of the polymerization inhibitor (methoquinone) was 1300 ppm with respect to the thermal radical polymerizable substance and the polymerization inhibitor (t-butylparabenzoquinone) was not blended. A plurality of insulating films for underfill were prepared under the conditions and conditions described above, and the characteristics of the films immediately after the production and after storage for 1 week at 40 ° C. were evaluated. The results are shown in Table 1.
[Example 5]
30 parts by mass of YX7200B35 (number average molecular weight of about 10,000, DSC glass transition temperature 149 ° C., epoxy equivalent 8000) as phenoxy resin, DIC Corporation N-695 (cresol novolac type, softening point) as epoxy resin 90 to 100 ° C.), 20 parts by mass as organic peroxide, Perhexa 25B (manufactured by NOF Corporation, 1 minute half-life temperature 180 ° C., molecular weight 290.45), 1 part by mass, and OX 50 (Nippon Aerosil Co., Ltd., An insulating film for underfill was prepared under the same composition and conditions as in Example 1 except that 40 parts by mass of hydrophilic fumed silica, BET specific surface area of 50 m ² / g, and average particle size of about 0.05 μm were blended. A plurality of sheets were produced and their characteristics were evaluated. The results are shown in Table 1.
[Example 6]
30 parts by mass of YX7200B35 manufactured by Mitsubishi Chemical Corporation as the phenoxy resin, 20 parts by mass of N-695 (cresol novolac type) manufactured by DIC Corporation as the epoxy resin, 2 parts by mass of 2MAOK · PW as the epoxy curing agent, organic peroxide Insulating film for underfill under the same composition and conditions as in Example 1 except that 1 part by weight of Perhexa 25B (manufactured by NOF Corporation) and 25 parts by weight of OX50 (Nippon Aerosil Co., Ltd.) are blended as silica. A plurality of sheets were manufactured and the characteristics were evaluated. The results are shown in Table 1.
[Example 7]
30 parts by mass of YX7200B35 manufactured by Mitsubishi Chemical Corporation as a phenoxy resin, 1 part by mass of Perhexa 25B (manufactured by NOF Corporation) as an organic peroxide, and 25 parts by mass of OX50 (Nippon Aerosil Co., Ltd.) as silica Except for this, a plurality of underfill insulating films were produced under the same composition and conditions as in Example 1, and the characteristics were evaluated. The results are shown in Table 1.
[Comparative Example 1]
Except that the polymerization inhibitor (t-butylparabenzoquinone) was not blended, a plurality of insulating films for underfill were produced under the same composition and conditions as in Example 1, and immediately after production and at 40 ° C. for 1 week. The characteristics of the film after storage were evaluated. The results are shown in Table 1.
[Comparative Example 2]
Perbutyl O (manufactured by NOF Corporation, 1 minute half-life temperature 134 ° C., molecular weight 216.32) was used as an organic peroxide in an amount of 1 part by mass, and the polymerization inhibitor (t-butylparabenzoquinone) was not blended. Except for this, a plurality of insulating films for underfill were produced under the same composition and conditions as in Example 1, and the characteristics of the films immediately after production and after storage at 40 ° C. for 1 week were evaluated. The results are shown in Table 1.
[Comparative Example 3]
32 parts by mass of phenoxy resin (Mitsubishi Chemical Corporation, 1256B40), epoxy resin (manufactured by DIC Corporation, HP4710 (naphthalene type, softening point 85-105 ° C., prepared in advance using a methyl ethyl ketone solution having a solid content of 70%) 32 Part by mass, epoxy resin (Mitsubishi Chemical Co., Ltd. jER806, bisphenol F type, liquid, epoxy equivalent 160-170), part by mass, epoxy hardener (manufactured by Shikoku Kasei Kogyo Co., Ltd., 2MAOK-PW), 4 parts by mass, flux ( 0.8 parts by mass of adipic acid) and 8 parts by mass of silica (manufactured by Nippon Aerosil Co., Ltd., OX50) were blended, and a plurality of insulating films for underfill were produced in the same manner as in Example 1, and immediately after production. The characteristics of the film after storage for 1 week at 40 ° C. were evaluated, and the results are shown in Table 1.
[Comparative Example 4]
33 parts by mass of phenoxy resin (Mitsubishi Chemical Co., Ltd., 1256B40), epoxy resin (DIC Co., Ltd., N-673 (cresol novolac type, softening point 73-82 ° C., pre-adjusted methyl ethyl ketone solution with a solid content of 70%) 38 parts by mass, 29 parts by mass of epoxy resin (Mitsubishi Chemical Co., Ltd. jER806), 4.2 parts by mass of epoxy curing agent (manufactured by Shikoku Kasei Kogyo Co., Ltd., 2MAOK-PW), 0.8 mass of flux (adipic acid) Part, 8.4 parts by mass of silica (made by Nippon Aerosil Co., Ltd., OX50), other than that, a plurality of insulating films for underfill were produced in the same manner as in Example 1, and immediately after production and at 40 ° C. for 1 week The characteristics of the film after storage were evaluated, and the results are shown in Table 1.

In Examples 1 to 7, pressure bonding could be performed without any problem immediately after the production and after storage at 40 ° C. for 1 week.
In Comparative Example 1, large voids were generated after storage at 40 ° C. for 1 week. Considering the evaluation result of the melt viscosity η ^* ₃ , it is presumed that the curing progressed during storage and the fluidity was greatly reduced.
In Comparative Example 2, an organic peroxide having a low one-minute half-life temperature used in the anisotropic conductive film was used, but voids were formed immediately after the production, and poor bonding was confirmed. . Since the curing rate was too high, the fluidity of the resin was insufficient, and voids and poor bonding were considered to occur. In Comparative Examples 3 and 4, voids occurred immediately after fabrication. Considering the evaluation result of the melt viscosity η ^* ₂ , it is considered that the outgas component contained in the film expanded when the curing was slow and the solder melting temperature was reached.

  The insulating film for underfill according to the present invention exhibits plasticity and fluidity in the early stage of the process of joining the semiconductor chip and the circuit board, and is sufficiently cured in the later stage of the process, and further heated once. Since it has a technical effect with high practical value that it is excellent in storage stability for a long time even after, it is high in each field of industry, especially in the field of electrical and electronic industry including manufacturing of semiconductor devices. Has availability.

1: Semiconductor chip 2a: Electrode 2b: Counter electrode 3: Solder 4: Insulating film for underfill 5: Circuit board

Claims (15)

The melt viscosity η ^* ₁ at 110 ° C. is 1 × 10 ^{1 to} 5 × 10 ³ Pa · s,
The melt viscosity η ^* ₂ at 130 ° C. is 5 × 10 ² to 1 × 10 ⁵ Pa · s, and
An insulating film for underfill in which the ratio η ^* ₃ / η ^* ₂ of the melt viscosity η ^* ₃ at 130 ° C. after being held at 40 ° C. for 1 week and the above η ^* ₂ is less than 3.   The insulating film for underfill according to claim 1, wherein the content of conductive particles is 5% by mass or less.   It contains a resin for film formation, a thermal radical polymerizable substance, a thermal radical generator, a polymerization inhibitor and a flux agent, and the content (mass) of the polymerization inhibitor is the amount (mass) of the thermal radical polymerizable substance. The insulating film for underfill according to claim 1 or 2, wherein the content is 600 to 10,000 ppm.   The insulating film for underfill according to claim 3, wherein the one-minute half-life temperature of the thermal radical generator is 140 to 200 ° C.   The insulating film for underfill according to claim 3, wherein the polymerization inhibitor is a quinone.   The insulating film for underfill according to any one of claims 3 to 5, further comprising an epoxy resin and a latent curing agent.   The initial latent curing agent is 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2,4-diamino-6- [2′-methylimidazolyl- ( The insulating film for underfill according to claim 6, which is at least one selected from 1 ′)]-ethyl-s-triazine isocyanuric acid adduct.   An exothermic curve in the range of 50-250 ° C measured by a differential scanning calorimeter has a maximum value in the range of 130-170 ° C, and at least one exothermic peak has a half width of 25-60 ° C. Item 8. The underfill insulating film according to any one of Items 1 to 7.   The insulating film for underfill according to any one of claims 1 to 8, wherein an exothermic curve in a range of 50 to 250 ° C measured by a differential scanning calorimeter has at least two maximum values. A semiconductor chip on which a soldered electrode is formed and a circuit board on which a counter electrode facing the soldered electrode is formed via the underfill insulating film according to any one of claims 1 to 9. A method of manufacturing a semiconductor device to be joined,
a) a step of applying the underfill insulating film on a wafer having a soldered electrode under vacuum;
b) dividing the wafer into individual semiconductor chips with an insulating film for underfill;
c) With the semiconductor chip and the circuit board, the electrode of the semiconductor chip and the counter electrode of the circuit board are respectively substantially abbreviated in a temperature condition where the maximum temperature is equal to or higher than the melting point temperature of the solder mounted on the chip. And a thermocompression bonding step of thermocompression bonding so as to contact on the center line. A semiconductor chip on which a soldered electrode is formed, an insulating film for underfill according to any one of claims 1 to 9, and a circuit board on which a counter electrode facing the soldered electrode is formed. A laminated body joined in order,
The laminated body, wherein at least a part of the soldered electrode is in electrical contact with at least a part of the counter electrode.   In a place where at least a part of the soldered electrode is in electrical contact with at least a part of the counter electrode, the under electrode is interposed between at least a part of the soldered electrode and at least a part of the counter electrode. The laminate according to claim 11, wherein there is no insulating film for fill.   The through-hole is formed in the said insulating film for underfills in the location where at least one part of the said electrode with a solder is in electrical contact with at least one part of the said counter electrode. Laminated body.   A semiconductor device comprising the stacked body according to claim 11. An electric / electronic apparatus comprising the semiconductor device according to claim 14.