KR20080013472A - Method for connecting semiconductor chip with bamps to substrate - Google Patents

Abstract

A method for connecting a semiconductor chip with bamps to a substrate is provided to improve attachment reliability and to reduce connection time by using a specific relationship between a polymeric initiator and a compression temperature. An isotropic conductive adhesive(20) is interposed between a semiconductor chip with bamps and a substrate. The isotropic conductive adhesive contains a radical polymer material, a radical polymeric initiator, and a conductive particle(24) which is transformed by pressure. In case a heating time S(minute) is 1 S 30, a half-life temperature during 1 minute of the radical polymeric initiator is T1(°C), and a pressurizing temperature is T2(°C), relationships of T1 + x = T2 and 15 x 70 are satisfied. The pressurizing temperature is in the range from 140 to 240 °C. The radical polymer material is selected from acrylate, methacrylate, maleimide, and styrene derivative. The radical polymeric initiator is selected from peroxyketal, peroxyester, and dialkyl peroxide.

Description

METHOOD FOR CONNECTING SEMICONDUCTOR CHIP WITH BAMPS TO SUBSTRATE}

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the connection state of the chip | tip with a board | substrate and board | substrate which concerns on one Embodiment of this invention.

2 is a cross-sectional view showing a connection method of a conventional chip with a vamp and a substrate.

3 is a cross-sectional view showing a connection state of a conventional chip with a vamp and a substrate.

It is sectional drawing which shows the connection state of the other conventional chip | tip with a vamp and a board | substrate.

The present invention relates to a method for connecting a semiconductor chip with a pulse, such as an IC and an LSI, to a substrate.

With the recent miniaturization and thinning of electronic devices, the establishment of new high-density packaging technology for semiconductor devices is required. Flip chip mounting has been proposed as a method of mounting a semiconductor device having a size substantially the same as the size of a semiconductor element. Flip chip mounting has been attracting attention as a method for mounting a semiconductor device in a minimum area in recent years in miniaturization and high density of electronic devices. A vamp is formed on the aluminum electrode of the semiconductor element used for flip chip mounting, and the vamp and the wiring on the circuit board are electrically joined using an anisotropic conductive adhesive or the like. These vamps include solder vamps and gold stud vamps.

2 is a cross-sectional view showing a conventional method for connecting a semiconductor chip with a vamp and a substrate.

First, the anisotropic conductive adhesive 20 is pressed onto the circuit terminal 12 of the substrate 10, and then the chipping chip 30 is positioned on the circuit terminal 12 of the substrate 10 (FIG. 2 ( a)). In that state, it heat-pressurizes from the upper side of the chip | tip 30 with a vamp by a crimping head (not shown), fluidizes the resin 22 of the anisotropic conductive adhesive 20, and at the same time, The electroconductive particle 24 is made to contact between the circuit terminals 12 which oppose the vamp 32 (FIG. 2 (b)).

At this time, when the curing speed of the resin 22 of the anisotropic conductive adhesive 20 is slow, the resin 22 is boiling even after the particles 24 are deformed, and the curing of the resin is insufficient even after releasing the crimp. Move a little and then stop. FIG. 3 is a diagram showing such a connection, wherein the vamp 32 of the chip 30 with the vamp, the circuit terminal 12 of the opposing substrate 10, and the conductive particles 24 of the anisotropic conductive adhesive 20 therebetween. ) Is an enlarged view in a connected state. In the pressurized state of FIG. 3A, the resin 22 flows, and the particles 24 are also sufficiently deformed. However, as shown in Fig. 3 (b), since the curing of the resin 22 is slow after pressing release, the particles 24 harden due to the deformation of the particles 24, and a sufficient contact area is not obtained.

In addition, when the curing rate of the anisotropic conductive adhesive 20 is high, the flow of the resin 22 stops while the deformation of the particles 24 is insufficient (FIG. 4). Due to the rapid flow stop, deformation was incomplete, or interface peeling occurred from the deformation stress of the cured product, adversely affecting the adhesive strength and reliability of the connecting body.

An object of the present invention is to provide a method for connecting a semiconductor chip with a vamp (hereinafter sometimes referred to as a chip with a vamp) and a substrate in a short time with high adhesion reliability.

MEANS TO SOLVE THE PROBLEM In view of the said subject, the present inventors earnestly researched and, when the relationship between a polymerization initiator and a crimping temperature have a specific relationship, they discovered that the objective of this invention can be achieved, and completed this invention.

According to the present invention, the following method for connecting a semiconductor chip with a vamp and a substrate is provided.

1. A method of connecting a semiconductor chip with a vamp having a height of 10 to 30 µm with an anisotropic conductive adhesive between a substrate and a heat pressurized by a crimping head of a crimping device, wherein the anisotropic conductive adhesive is radically polymerizable. Containing the substance, the radical polymerization initiator and the electroconductive particle deformed by pressure, the heating time S (seconds) is 1 ≤ S ≤ 30, and the 1 minute half-life temperature of the radical polymerization initiator is T ₁ (° C), the compression temperature a method of connecting the semiconductor chip and the bumps attached to the substrate when a T ₂ (℃), satisfies the following expression.

T ₁ + x = T ₂

15 ≤ x ≤ 70

2. The compression temperature T ₂ is 140~240 ℃, in which the radical polymerizing the material of the anisotropic conductive adhesive, acrylate, methacrylate, and at least one selected from a maleimide, a styrene derivative, a radical polymerization initiator (1) The connection method of 1 base material which is at least 1 sort (s) chosen from peroxy ketal, peroxy ester, and dialkyl peroxide.

ADVANTAGE OF THE INVENTION According to this invention, the connection method of the chip | tip with a vamp and board | substrate with high adhesive reliability can be provided.

Implement the invention  Best form for

The connecting method of the chip | tip with a vamp of this invention and a board | substrate is a method of heating and pressurizing with the crimping head of a crimping apparatus, and connecting an anisotropic conductive adhesive between a chip | tip with a vamp and a board | substrate. The anisotropic conductive adhesive contains a radical polymerizable substance, a radical polymerization initiator, and conductive particles deformed by pressure. The heating time S (seconds) at the time of contact is 1 ≤ S ≤ 30, and the following formula is satisfied when the half-life temperature of the radical polymerization initiator is T ₁ (° C) and the pressing temperature is T ₂ (° C). do.

T ₁ + x = T ₂

15 ≤ x ≤ 70

Heating time S is 1-30 second, Preferably it is 1-10 second, More preferably, it is 1.5-9 second, More preferably, it is 2-7 second.

If heating time is less than 1 second, hardening may be inadequate and reliability may fall. If heating time exceeds 30 second, there exists a problem of adhesive reliability but productivity may fall.

At this time, the compression temperature T ₂ (℃) is, is usually 140~240 ℃, preferably 140~230 ℃, more preferably 160~230 ℃, more preferably 180~220 ℃.

If the crimping temperature T ₂ is less than 140 ° C., the curing may be insufficient and the reliability may decrease. If the T ₂ exceeds 240 ° C., the curing may be too fast and the connection resistance may increase or may not be connected.

Moreover, pressurization pressure is 10-150 Mpa normally with a vamp area, Preferably it is 15-120 Mpa, More preferably, it is 20-100 Mpa. Pressurization time is the same as heating time.

If the pressurization pressure is less than 10 MPa, the deformation of the particles may be insufficient, the connection resistance may be increased or not connected. If the pressurization pressure exceeds 150 MPa, the vamp deforms and there is a fear that the adjacent vamps may shorten.

The anisotropically conductive adhesive agent used by this invention contains a radically polymerizable substance, a radical polymerization initiator, and electroconductive particle.

A radically polymerizable substance is a substance which has a functional group superposing | polymerizing by radical, and an acrylate, a methacrylate, a maleimide compound, a styrene derivative, etc. are mentioned. The radically polymerizable substance can be used in any one of a monomer and an oligomer, and it is also possible to use a monomer and an oligomer together. Specific examples of (meth) acrylates include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimetholpropane triacrylate, and tetrameth. Tyrolmethanetetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypoly Ethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloyloxyethyl) isocyanurate and their corresponding methacrylates. Preferably, they are tricyclo decanyl acrylate and urethane acrylate. These may be used alone or in combination.

As a maleimide compound, at least 2 maleimide groups are contained in a molecule | numerator, for example, 1-methyl- 2, 4-bismaleimide benzene, N, N'-m-phenylene bismaleimide, N, N ' -p-phenylenebismaleimide, N, N'-m-toluylenebismaleimide, N, N'-4,4-biphenylenebismaleimide, N, N'-4,4- (3, 3'-dimethyl-biphenylene) bismaleimide, N, N'-4,4- (3,3'-dimethyldiphenylmethane) bismaleimide, N, N'-4,4- (3,3 '-Diethyldiphenylmethane) bismaleimide, N, N'-4,4-diphenylmethanebismaleimide, N, N'-4,4-diphenylpropanebismaleimide, N, N'-4 , 4-diphenyletherbismaleimide, N, N'-3,3'-diphenylsulfonbismaleimide, 2,2-bis (4- (4-maleimidephenoxy) phenyl) propane, 2,2 -Bis (3-s-butyl-4-8 (4-maleimidephenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidephenoxy) phenyl) decane, 4,4'-cyclo Hexylidene-bis (1- (4-maleimidephenoxy) -2-cyclohexylbenzene, 2,2-ratio (4- (4-maleimidophenoxy) phenyl) hexafluoropropane and the like. These can be used alone even also in combination.

As the radical polymerization initiator, a radical polymerization initiator having a half-life temperature T ₁ (° C.) that satisfies the following expression with respect to the crimping temperature T ₂ (° C.) is used.

T ₁ + x = T ₂

15 ≤ x ≤ 70

Specifically, it decomposes | dissolves by heating, such as a peroxide compound and an azo type compound, and produces | generates a free radical, A diacyl peroxide, a peroxydicarbonate, a peroxy ester, a peroxy ketal, a dialkyl peroxide, a hydroperoxide, Thus the silyl peroxide compression temperature T ₂ (℃) from, can be selected. Preferably, it is selected from peroxyester, dialkyl peroxide, hydroperoxide, silyl peroxide, dialkyl peroxide.

As peroxy ester, cumyl peroxy neodecanoate, 1,1,3,3- tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy nodecanoate, t- Hexyl peroxy neodecanoate, t-butylperoxy pivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di (2 -Ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, L-hexylperoxy-2-ethylhexanoate, L-butylperoxy-2-ethyl Hexanonate, t-butylperoxyisobutylate, 1,1-bis (t-butylperoxy) cyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5- Trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluoylperoxy) hexane, t-butylperoxyisopropylmonocarbonate, t-butylperoxy- 2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxy acetate and the like can be used.

Examples of the dialkyl peroxides include α, α'-bis (t-butylperoxy) diisopropylbenzene, dicumylperoxide, 2,5-dimethyl-2,5- (2-ethylhexanoylperoxy) hexane, 2 , 5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butyl cumyl peroxide and the like can be used.

As the hydroperoxide, diisopropyl benzene hydroperoxide, cumene hydroperoxide, or the like can be used.

Examples of the diacyl peroxide include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, Benzoyl peroxy toluene, benzoyl peroxide, etc. can be used.

As peroxydicarbonate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t- butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxy peroxydicarbonate, di (2 -Ethylhexyl peroxy) dicarbonate, dimethoxybutyl peroxy dicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate, etc. can be used.

As peroxy ketal, 1, 1-bis (t-hexyl peroxy) -3, 3, 5- trimethyl cyclohexane, 1, 1-bis (t-hexyl peroxy) cyclohexane, 1, 1-bis (t -Butyl peroxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) decane, n-butyl-4 , 4-di- (t-butylperoxy) palylate and the like can be used.

Examples of the silyl peroxide include t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide and tris (t-butyl) Vinyl silyl peroxide, t-butyl triaryl silyl peroxide, bis (t-butyl) diallyl silyl peroxide, tris (t-butyl) allyl silyl peroxide, etc. can be used.

These initiators may be used alone or in combination, or may be used by mixing a decomposition accelerator, an inhibitor and the like.

In said formula, x becomes like this. Preferably it is 15-70, More preferably, it is 20-60.

If x is less than 15, the curing may be insufficient and the connection resistance may increase. If x is more than 70, the curing may be too fast and the connection resistance may increase or fail to connect.

The electroconductive particle used by this invention is particle | grains deform | transformed by pressurization, Although it does not specifically limit, For example, metal particles, such as Au, Ag, Ni, Cu, solder, carbon, etc. can be used. Au, Ag, platinum group precious metals are preferable, and Au is more preferable.

It is also possible to use a surface coated with transition metals such as Ni with noble metals such as Au. In addition, the conductive layer described above is formed by coating or the like on non-conductive glass, ceramic, plastic, etc., and the outermost layer is deformable by heating and pressing, when the outermost layer is made of noble metals and plastics, or in the case of hot melt metal particles. Since the contact area with an electrode increases at the time of connection and reliability improves, it is preferable.

If the relationship between the polymerization initiator and the crimping temperature satisfies the above relationship, a connection as shown in Fig. 1 is obtained. Specifically, the anisotropic conductive adhesive 20 is pressed onto the circuit terminal 12 of the substrate, the chip with chip is positioned on the circuit terminal 12 of the substrate, and heated and pressed from above the chip with chip. While the resin 22 of the anisotropic conductive adhesive 20 is fluidized, the conductive particles 24 of the anisotropic conductive adhesive 20 are interposed between the circuit terminals 12 that face the vamp 32. While contacting with the circuit terminal 12, it is sufficiently deformed. After stopping the heating pressurization, in the present invention, the flow of the resin 22 can be stopped while the conductive particles 24 are sufficiently deformed.

As a result, as shown in FIG. 1, the connection excellent in adhesive strength and reliability is obtained.

The semiconductor chip which has the vamp (protrusion conductor) used by this invention is 10-30 micrometers in height of a vamp.

In the case of a semiconductor chip, the connection terminal is usually made of aluminum, but the surface of the semiconductor chip may further be plated with precious metals such as nickel, gold, platinum, or the like, and projections made of nickel, gold vamp, solder balls, or the like may be further formed. .

The substrate can also be a conventional one. For example, a circuit board having ITO wiring, IZO wiring, Al, Cr, Ag wiring, laminated wiring thereof, or the like can be used on Corning glass or soda glass.

EXAMPLE

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely based on an Example.

Example  1-12, Comparative example  1 to 6

A glass substrate (Corning # 7059, external appearance 38mm × 28mm, thickness 0.7mm, surface) using the mounting stage (head temperature and heating time) shown in Table 1, using a metal stage and a head made of ceramic heater (5mm x 30mm). ITO (Indium Tin Oxide) wiring pattern (with a width of 50 µm and a pitch of 50 µm) on an IC chip (1.7 mm x 17.2 mm, 0.55 mm thick, 50 μm x 50 μm x 15 μm (Vamp) Height) and the pitch of 50 micrometers of vamp) were heated and pressurized under 50 MPa (samp area conversion) load. As the thermosetting adhesive, the following anisotropic conductive films (ACFs) were used.

(1) ACF a

Thickness: 25㎛

The resin component of ACF a is a phenoxy resin, a polyfunctional acrylic compound, a urethane acrylate, a silane coupling agent, and a radical polymerization initiator is 2,5-dimethyl-2,5- (2-ethylhexanoyl peroxy) Hexane (1 min half-life temperature: 119 ° C.).

(2) ACF b

Thickness: 25㎛

The same resin component as ACF a except that the radical polymerization initiator of ACF a was changed to 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane (1 minute half-life temperature: 147 ° C). And it was set as ACF b using electroconductive particle.

(3) ACF c

Thickness: 25㎛

Except having changed the radical polymerization initiator of ACFa into dicumyl peroxide (1 minute half life temperature: 175 degreeC), it was set as ACFc using the same resin component and electroconductive particle as ACFa.

The connection state of the board | substrate after IC chip mounting was evaluated as follows. The results are shown in Table 1.

<Measuring connection status>

The connection resistance immediately after connection of the board | substrate after IC chip mounting was measured by the 4-terminal method. The average value of 10 samples was made into connection resistance (ohm), and it evaluated by four steps of (circle), (circle), (x), and OPEN on the following references | standards.

◎: 1 less than

○: 1 or more less than 5 Ω

×: 5Ω or more

OPEN: No conduction, no connection resistance can be measured.

From the result of Table 1, in Examples 1-12 whose x is 15-70 degreeC, it turns out that connection resistance is low and it is a favorable connection state. On the other hand, in Comparative Examples 1-6 in which x was less than 15 or more than 70, the connection resistance was high and OPEN defect occurred.

The connection method of the semiconductor chip with a vamp of this invention and a board | substrate can be performed extensively in the field of electrical / electronics, such as electro-optical devices, such as a liquid crystal device.

Claims (2)

In the method of connecting an anisotropic conductive adhesive between a semiconductor chip with a vamp having a height of 10 to 30 µm and a substrate by heating and pressure-bonding by a crimping head, the anisotropic conductive adhesive is a radical polymerizable substance or radical polymerization. Conductive particles deformed by the initiator and pressurization, the heating time S (seconds) is 1 ≤ S ≤ 30, the half-life temperature of the radical polymerization initiator is T ₁ (° C), the compression temperature is T ₂ ( The method of connecting a semiconductor chip with a vamp and a board | substrate which satisfy | fills the following formula when it is set to (degree. C.). T ₁ + x = T ₂ 15 ≤ x ≤ 70 The method of claim 1 wherein the pressing temperature T ₂ is 140~240 ℃, in which the radical polymerizing the material of the anisotropic conductive adhesive, acrylate, methacrylate, and at least one kind selected from maleimide, styrene derivatives, The radical polymerization initiator is at least 1 sort (s) chosen from peroxy ketal, a peroxy ester, and a dialkyl peroxide.

Images