JP2842226B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device which is mounted on a substrate, such as a thermal recording head device, and is sealed with a cured product of an epoxy resin composition of a semiconductor element. The present invention relates to a semiconductor device in which warpage of a substrate when sealed with a material is prevented as much as possible.

[0002]

2. Description of the Related Art In recent years,
Large semiconductor devices such as MCM and BGA have been developed. The substrate of these devices is made of copper, a glass epoxy laminate, BT resin, ceramics, a polyimide film, or the like. However, as the size of the device increases, the sealing area of the resin composition tends to be wider. . Also, the sealing method has changed, and a method of sealing only one side has been adopted for the purpose of reducing the thickness of the device.

[0003] When sealing such a device, a thermosetting resin composition such as an epoxy resin sealing material is used. When sealing is performed, the substrate may be warped, which may cause a problem that reliability of the semiconductor device is impaired and mounting of the device becomes impossible.

[0004] In particular, a thermal recording head (hereinafter referred to as TPH)
In this case, the problem of substrate warpage is great.

That is, a thermal recording head used in a thermal facsimile or the like generally has a heating substrate having a heating element circuit and a resin driving circuit substrate having a driving circuit joined at their ends to generate the heat. A driving integrated circuit (IC) is mounted close to the joint end of the substrate surface or the driving circuit substrate surface, and the integrated circuit, the heating element circuit and the driving circuit are connected to a wiring portion such as a bonding wire. In this case, a flip-chip bonding method or a wire bonding method is generally known as an IC mounting method.

[0006] After these bonding, a silicone resin is conventionally used to prevent moisture or conductive foreign matter from entering the bonding portion of the driving IC and the exposed surface of the wiring material of the heating substrate and the driving circuit board. Protective sealing has been used. Further, a head cover is generally mounted over the silicone-based sealing portion for the purpose of mechanically protecting the silicone-based sealing portion and guiding the recording paper discharged by the platen roller. In particular, in the mounting method in the wire bonding method, the mechanical strength of the bonding wire is extremely weak even after being protected and sealed with a silicone resin, so whether a head cover is attached to facilitate handling during the manufacturing process, Alternatively, a jig having a head cover function is required. Also, in the flip chip bonding method, a head cover is required to mechanically protect the elements of the driving IC after protection and sealing with a silicone resin or the like.

[0007] That is, conventionally, as described above, the resin used for the protective sealing of such a driving IC is mainly a silicone resin, and this silicone resin has sufficient environmental resistance and electrical insulation. However, the function of mechanical protection is not sufficient, and a head cover must be attached to the protective sealing portion, so that there is a problem that the number of working steps is large and the material cost is high.

[0008] Therefore, in order to provide the function of mechanical protection of the driving IC and the bonding wire to the sealing resin itself instead of the head cover, an epoxy having a large hardness is used instead of a silicone resin which has been generally used so far. A method of sealing with a resin composition has been developed.

However, when the epoxy resin composition is used, a warp is generated after the resin sealing, especially on a driving circuit board composed of a glass epoxy laminate, and this warp causes a TP.
If the reliability of the H device is impaired and the warp width is large, there is a problem that printing becomes impossible.

It has been pointed out that a difference in the curing shrinkage ratio due to a difference in the coefficient of linear expansion between the substrate and the sealing resin has been pointed out as a cause of such a warp. A method of making the linear expansion coefficients equal is employed.

[0011] However, even if the linear expansion coefficients of the substrate and the sealing resin are made equal to each other, the contraction tendencies of the two are different from each other, which makes it difficult to reduce the amount of warpage. As a result of blending in a large amount, there is a problem that the viscosity of the resin composition for sealing is increased, the fluidity is reduced, the workability is reduced, and the filling property is deteriorated. In this case, there is a method of using a solvent to lower the viscosity in order to improve the workability, but the solvent may not be completely removed after curing, and the reliability of the semiconductor device may be impaired.

In the case where the substrates having different coefficients of linear expansion are sealed with a resin as in a TPH apparatus, warping is prevented by a method of measuring the coincidence of the coefficients of linear expansion due to the high content of the filler as described above. It is difficult.

The present invention has been made in view of the above circumstances, and when a semiconductor element mounted on a resin substrate is sealed with a cured product of an epoxy resin composition, a large amount of a filler or the like is blended. It is an object of the present invention to provide a semiconductor device in which occurrence of warpage of a substrate is prevented as much as possible without matching the coefficient of linear expansion with the substrate.

[0014]

Means and Action for Solving the Problems The present inventors have
In order to achieve the above object, we conducted intensive studies and analyzed the tendency of the epoxy resin (sealing resin) and the curing shrinkage of the substrate in detail. As a result, the semiconductor element mounted on the substrate such as glass epoxy resin was sealed with epoxy resin sealing material. During sealing, when the substrate and the sealing resin are cooled from a high temperature, a large shrinkage occurs from the glass transition temperature (Tg) of the substrate to a temperature region about 30 ° C. lower than this, while a temperature region lower than this temperature. In addition to finding that almost constant small shrinkage occurs, it has been found that warping of the substrate can be prevented by lowering the Shore D hardness in a temperature region where a large shrinkage of the epoxy resin composition used for sealing occurs. .

That is, the hardness of the resin is suppressed to a constant value within a temperature range in which the shrinkage of the substrate is large. More specifically, the thickness of the epoxy resin composition excluding the inorganic filler is 1.5 mm or more. By performing sealing using an epoxy resin composition having a Shore D hardness of 60 or less at a temperature 30 ° C. ± 5 ° C. lower than the glass transition temperature of the substrate, and 25 or more at 25 ° C. , The stress generated between the sealing resin and the substrate can be reduced, so that the warpage generated on the substrate can be prevented as much as possible without blending a large amount of the filler with the same linear expansion coefficient as that of the substrate. It has been found that it is not necessary to mix a large amount of filler, so that the workability is good and the fillability is good.

In particular, in the case of a TPH apparatus having two types of substrates having different coefficients of linear expansion, the Shore D hardness of the cured product is 60 or less at a temperature 30 ° C. ± 5 ° C. lower than the glass transition temperature of a substrate having a large coefficient of linear expansion. It was found that if sealed with a material, shrinkage of the substrate would not be easily hindered, and stress would not easily be generated between the two, and as a result, warpage could be prevented.
The present invention has been accomplished.

Accordingly, the present invention provides (1) a semiconductor device comprising an IC mounted on a substrate such as a glass epoxy resin laminate and sealed with a cured product of an epoxy resin composition.
As the epoxy resin composition, a cured product having a thickness of 1.5 mm or more obtained by removing the inorganic filler from the epoxy resin composition has a Shore D hardness of 30 ° C. ± 5 ° C. lower than the glass transition temperature of the substrate. A semiconductor device using an epoxy resin composition of not more than 60 and not less than 25 at 25 ° C., and (2) a resin-made drive having a heating substrate having a heating element circuit and a driving circuit A circuit board, and a driving IC mounted on the heat-generating substrate or the driving circuit board.
C and the heating element circuit and the driving circuit are connected to each other via a wiring portion such as a bonding wire. The driving IC and each wiring portion of the thermal recording head are sealed with a cured product of an epoxy resin composition. In the thermal recording head device, the epoxy resin composition is obtained by removing the inorganic filler from the epoxy resin composition.
The Shore D hardness of the cured product having a thickness of 5 mm or more is 3 times higher than the glass transition temperature of the substrate having a large linear expansion coefficient of the two substrates.
Not more than 60 at a temperature lower by 0 ° C. ± 5 ° C. and 25
Provided is a thermosensitive recording head device using an epoxy resin composition having a temperature of 25 ° C. or more.

Hereinafter, the present invention will be described in more detail. The epoxy resin composition used for sealing in the semiconductor device of the present invention is preferably a liquid at room temperature, and more preferably a solventless type. As the curable epoxy resin constituting the solvent-free liquid epoxy resin composition, those having two or more epoxy groups in one molecule can be used,
There is no particular limitation on the molecular structure, molecular weight, etc., as long as it can be cured by various curing agents as described below,
Conventionally known various types can be used. Specifically, for example, an epoxy resin synthesized from various novolak resins including epichlorohydrin and bisphenol, an epoxy compound containing an ester bond derived from an organic acid represented by the following general formula (1), an epoxy compound represented by the following general formula (2) ), An epoxy compound derived from polybutadiene, an alicyclic epoxy resin or an epoxy resin into which halogen atoms such as chlorine and bromine atoms have been introduced.

[0019]

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Further, a silicone-modified epoxy resin can also be used. The silicone-modified epoxy resin is represented by the following formulas (8) to (10) and hydrogen atoms in the compounds represented by (3) to (7). Copolymers obtained by an addition reaction with an alkenyl group of an alkenyl group-containing epoxidized novolak resin, and the like, and in particular, a copolymer obtained from the compound (4) and the compound (5) are preferably used.

[0021]

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[0022]

Embedded image (However, in the above formulas (8) to (10), p and q usually represent positive numbers represented by 1 ≦ p ≦ 10 and 1 ≦ q ≦ 3.)

Among these epoxy resins, a bisphenol type epoxy resin, an epoxy resin containing an ester bond derived from an organic acid, an epoxy resin derived from a compound containing a long-chain alkyl group, and a silicone-modified epoxy resin are preferred.

The use of the epoxy resin is not necessarily limited to one type, and two or more types may be used in combination.

In using the epoxy resin, a monoepoxy compound may be appropriately used in combination.
Specific examples of the monoepoxy compound include styrene oxide, cyclohexene oxide, propylene oxide, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, octylene oxide, dodecene oxide and the like.

On the other hand, specific examples of the curing agent include amine-based curing agents such as diaminodiphenylmethane, diaminophenylsulfone, and metaphenylenediamine; phthalic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride; A long-chain aliphatic acid anhydride represented by the following formula, an acid anhydride-based curing agent such as a silicone-modified acid anhydride represented by the following general formula (11), or two or more per molecule such as phenol novolak and cresol novolak And a phenol novolak curing agent having a hydroxyl group. Among these, an acid anhydride-based curing agent is preferably used to obtain a low-viscosity, low-stress epoxy resin composition.

[0027]

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[0028]

Embedded image (R ¹ is a C ₂ -C ₈ alkylene group, R ² , R ³ , R ⁴ are a methyl group, an ethyl group, a phenyl group, an alkenyl group, X is an alkoxy group, a propenyl group, an alkenyl group, and n is 0,1 ,
2, m is 0 or an integer of 1 or more, and 1 is 0, 1, 2.
R ⁵ is a hydroxyl group or an alkyl group. )

The amount of the curing agent used can be a usual amount, but is preferably in the range of 50 to 150 equivalent%, particularly preferably 80 to 110 equivalent%, based on the equivalent of the epoxy group of the epoxy resin.

Further, in the epoxy resin composition, for the purpose of accelerating the reaction between the curing agent and the epoxy resin,
Various curing accelerators, for example, imidazole or a derivative thereof, a tertiary amine derivative, a phosphine derivative, a cycloamidine derivative, and the like can be used in combination.
In addition, the compounding quantity of these hardening accelerators can also be made into a normal range.

Further, an inorganic filler can be blended in the epoxy resin composition. In this case, the kind of the inorganic filler to be used, a single use or a combination of a plurality of kinds is not limited, and is appropriately selected. Examples of the inorganic filler include one or two selected from natural silica such as crystalline silica and amorphous silica, synthetic high-purity silica, synthetic spherical silica, talc, mica, silicon nitride, boron nitride, and alumina. The above can be used.

In the present invention, the blending amount of the above-mentioned inorganic filler does not need to be high in order to make the coefficient of linear expansion with the substrate the same, but it is possible to use it within a range which does not affect workability. it can.

The epoxy resin composition may further contain a releasing agent such as a stress reducing agent, a carbon-functional silane for improving adhesion, waxes, fatty acids such as stearic acid and metal salts thereof, and a pigment such as carbon black, if necessary. , Dyes, antioxidants,
A surface treatment agent (such as γ-glycidoxypropyltrimethoxysilane), various conductive fillers, a thixotropic agent, and other additives can be blended. In particular, as the thixotropy-imparting agent, it is preferable to use finely divided spherical silica having an average particle size of 5 μm or less, and more preferably to use spherical silica having an average particle size of 2 μm or less.

The epoxy resin composition of the present invention can be composed of the above components. In this case, the epoxy resin composition obtained by removing the inorganic filler from the epoxy resin composition is 1.5 m.
m at a temperature 30 ° C. ± 5 ° C. lower than the glass transition temperature of the substrate of the semiconductor device in which the epoxy resin composition is sealed.
Below, it is necessary to be preferably 50 or less, more preferably 45 or less. If the Shore D hardness is more than 60, the warpage of the substrate becomes large, and the object of the present invention cannot be achieved. The cured product must have a Shore D hardness of 25 or more at 25 ° C., preferably 70 or more, more preferably 80 or more. If the Shore D hardness is lower than 25, the cured product may be used for sealing semiconductor devices. The hardness is insufficient, and sufficient impact resistance cannot be given to the semiconductor device.

When two or more substrates of a semiconductor device sealed with the epoxy resin composition of the present invention are present as in a TPH device, the hardness of the Shore D of the cured product is as follows:
It is based on a substrate having a large linear expansion coefficient, and is selected so that the Shore D hardness at a temperature 30 ° C. ± 5 ° C. lower than the glass transition temperature of the substrate is 60 or less.

The epoxy resin composition of the present invention is prepared by selecting the types and amounts of the above components so as to have the above hardness, and the preparation can be carried out by a usual method. There is no particular limitation on the order of mixing the components.

The semiconductor device of the present invention is obtained by sealing an IC mounted on a substrate with a cured product of the epoxy resin composition. In this case, the substrate is mainly composed of an organic resin. For example, a glass epoxy resin laminate, a BT resin, a polyimide film, and the like can be given. In this case, the glass epoxy resin laminate generally has a Tg of 12
0 to 170 ° C, coefficient of linear expansion (α) is 1.5 to 2.5 ×
10 ⁻⁵ / ° C., Tg of BT resin is 200 to 210 ° C., coefficient of linear expansion (α) is 1.5 to 4.5 × 10 ⁻⁵ / ° C., Tg of polyimide film is 280 to 300 ° C., coefficient of linear expansion (Α) is 1.7 to 4.3 × 10 ⁻⁵ / ° C. Among these, a semiconductor device using a glass epoxy resin laminate as a substrate particularly exhibits the effects described above in the present invention effectively.

Although the semiconductor device of the present invention includes a TPH device, the present invention is also effective for this TPH device. The TPH device includes a heating board having a heating element circuit and a resin driving circuit board having a driving circuit. A driving IC is mounted on the heating board or the driving circuit board. The above-mentioned driving IC of the thermal recording head in which the heating element circuit and the driving circuit are respectively connected via wiring portions such as bonding wires.
And each wiring portion is sealed with a sealing material.

The sealing by the sealing material in the TPH device will be described. For example, as shown in FIGS. 1 to 4, a heating substrate 1 having a heating element circuit (heating element) 1a
And a driving circuit board 2 having a driving circuit 2a at one end thereof, and a driving IC 3 is provided near the joining end of the heating substrate 1 or the driving circuit board 2 surface.
Is mounted along the bonding direction of the terminal.
Are connected to the heating element circuit 1a and the driving circuit 2a via wiring portions 4 and 5, such as bonding wires, respectively. It is sealed with an epoxy resin sealing material 7 having the same. In the figure, reference numeral 6 denotes a heat dissipation board.

In such a thermal recording head, the heat-generating substrate 1 is brought into contact with a platen roller 8 so that the heat-sensitive recording paper 9 is passed between the heat-generating substrate 1 and the platen roller 8.

The IC 3 is either mounted on the surface of the driving circuit board 2 as shown in FIGS. 1 to 3 or mounted on the heat generating substrate 1 as shown in FIG.

In this case, the TPH apparatus generally uses alumina ceramic (having a linear expansion coefficient of about 0.7) as a heating substrate.
× 10 ⁻⁵ / ° C.), a glass epoxy resin laminate is used as a driving circuit board, and when a wiring portion of a semiconductor element is sealed as described above, a wiring portion on the glass epoxy laminate is inevitable. The epoxy resin composition of the present invention is particularly effective for sealing such a TPH device.

[0043]

According to the semiconductor device of the present invention, even if the epoxy resin composition is used as a sealing material, the substrate hardly warps and has high reliability.

[0044]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

Examples 1 to 8 and Comparative Examples 1 to 4 Epoxy resin compositions were prepared according to the formulations shown in Table 1. Next, as shown in FIG. 5, a glass epoxy laminate (Tg = 142) on which eight semiconductor elements a of 7 mm × 7 mm square were mounted.
° C, linear expansion coefficient (Tg or less) 2.2 × 10 ^-5 / ° C, 50
mm × 20 mm, thickness 0.8 mm) b was set in a mold, and the prepared epoxy resin composition c was dropped at a thickness of 3 mm and cured at 100 ° C. for 1 hour and further at 150 ° C. for 2 hours. A resin-sealed semiconductor device d was manufactured.

The warpage (δ (mm)) of the semiconductor device d thus manufactured was measured at room temperature by the method shown in FIG.

In addition, the hardness of Shore D cured product of only the resin excluding the filler from each of the epoxy resin compositions shown in Table 1 was measured at 110 ° C. and 25 ° C., and the Shore D cured product containing the filler was measured. Hardness was measured at 110 ° C. Furthermore,
The glass transition temperature and the coefficient of linear expansion (30 to 50 ° C.) were also measured. The results are also shown in Table 1. Example 4 and Example 8
FIG. 7 is a graph showing the hardness of the epoxy resin composition with respect to the measurement temperature in comparison with the glass epoxy laminate.

[0048]

[Table 1]

[0049]

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[0050]

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Examples 9 to 15 and Comparative Examples 5 to 8 Epoxy resin compositions were prepared according to Table 2, and these compositions were mixed with spherical silica having an average particle size of 1 μm or less to impart thixotropy. The obtained composition was then heated at 110 ° C. for 1 hour.
After curing for 2 hours at 150 ° C., the Shore D cured product hardness of the resin alone without the filler was measured at 110 ° C. and 25 ° C., and the Shore D cured product hardness containing the filler was 1
It was measured at 10 ° C. Furthermore, the glass transition temperature and the coefficient of linear expansion (30 to 50 ° C.) were also measured.

Further, the TPH device was manufactured by actually sealing it, and the warpage of the TPH device after sealing was measured. FIG. 8 shows a method of measuring the amount of warpage. Here, in the TPH device, the heat generating substrate is made of alumina ceramic and has a linear expansion coefficient of 0.7 × 10 ^−5.
/ ° C, the driving circuit board is a glass epoxy laminate, the coefficient of linear expansion is 2.2 × 10 ^-5 / ° C, and the Tg is 140 ° C. The TPH device used next is shown. <TPH device A> The cross-sectional shape is as shown in FIG.
This is the size, and the dimensions in FIG. 4 are shown below. I: 18 mm II: 15 mm III: 25 mm IV: 7 mm <TPH device B> The cross-sectional shape is shown in FIG.
This is the size, and the dimensions in FIG. 4 are shown below. I: 10 mm II: 10 mm III: 15 mm IV: 5 mm The results are also shown in Table 2. The notes in the table are the same as in Table 1.

[0053]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a thermal recording head.

FIG. 2 is a cross-sectional view illustrating another example of a thermal recording head.

FIG. 3 is a cross-sectional view showing another example of a thermal recording head.

FIG. 4 is a cross-sectional view showing a thermal recording head used in Examples.

FIG. 5 is a perspective view showing a resin-sealed semiconductor device used in the example.

6 is a cross-sectional view illustrating a method for measuring the amount of warpage of the resin-sealed semiconductor device of FIG.

FIG. 7 is a graph showing the relationship between the resin temperature and the hardness of the cured resin.

FIG. 8 is a cross-sectional view showing a method for measuring the amount of warpage of the thermal recording head used in the example.

[Description of Signs] 1 Heating substrate 1a Heating element circuit 2 Driving circuit board 2a Driving circuit 3 Driving IC 4, 5 Wiring unit 6 Heat dissipation substrate 7 Sealing resin 8 Platen roller 9 Thermal recording paper a Semiconductor element b Glass epoxy Laminated plate c Sealing resin d Resin sealing type semiconductor device δ Warp amount

──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Futmori 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory Shin-Etsu Chemical Co., Ltd. (72) Toshio Shiobara Matsui, Usui-gun, Gunma Prefecture Hitomi Tamachi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) References JP-A-64-11354 (JP, A) JP-A-1-189150 (JP, A) JP-A-4 -59862 (JP, A) JP-A-4-351630 (JP, A) JP-A-7-256914 (JP, A) JP-A-7-242799 (JP, A) (58) Fields investigated (Int.Cl) . ^6, DB name) H01L 23/28 - 23/30 H01L 21/56 B41J 2/335

Claims (4)

(57) [Claims] 1. A semiconductor device in which an IC mounted on a substrate is sealed with a cured product of an epoxy resin composition.
As the epoxy resin composition, a cured product having a thickness of 1.5 mm or more obtained by removing the inorganic filler from the epoxy resin composition has a Shore D hardness of 30 ° C. ± 5 ° C. lower than the glass transition temperature of the substrate. A semiconductor device characterized by using an epoxy resin composition of not more than 60 and not less than 25 at 25 ° C. 2. The semiconductor device according to claim 1, wherein the substrate is a glass epoxy resin laminate. 3. A heating board having a heating element circuit and a resin driving circuit board having a driving circuit, and a driving IC is mounted on the heating board or the driving circuit board. The IC and the heating element circuit and the driving circuit are connected to each other via a wiring portion such as a bonding wire. The driving IC and the wiring portion of the thermal recording head are sealed with a cured product of an epoxy resin composition. In the thermal recording head device, a Shore D of a cured product having a thickness of 1.5 mm or more of the epoxy resin composition obtained by removing the inorganic filler from the epoxy resin composition is used.
An epoxy resin composition having a hardness of 60 or less at a temperature 30 ° C. ± 5 ° C. lower than the glass transition temperature of a substrate having a large linear expansion coefficient of the two substrates, and 25 or more at 25 ° C. Thermal recording head device. 4. The thermal recording head device according to claim 3, wherein the drive circuit board is a glass epoxy resin laminate.