JP2824569B2 - Electronic component manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electronic component, and more particularly, to a method of sealing an electronic component such as a semiconductor with a resin by printing, for example, an IC card, a memory card and a COB.
Module, COG module, PLCC, TAB, chip carrier, QFP, CSP, MCM, Flip c
The present invention relates to a method for manufacturing electronic components such as a chip, an LCD, a BGA, a T-BGA, a C-BGA, and a semiconductor package.

[0002]

2. Description of the Related Art Conventionally, as a resin sealing method for a semiconductor,
In general, (1) Transfer in which a semiconductor or the like mounted on a lead frame is set in a mold, and a solid sealing resin is heated, melted, injected, cured, and then released from the mold in the mold. A molding method and an injection sealing method, (2) a drop sealing method in which a liquid sealing resin is dropped and hardened on a semiconductor element with a dispenser, and (3) a liquid sealing resin is printed on the semiconductor element using a stencil. A printing and sealing method for hardening is performed.

However, the injection and transfer sealing method (1) has many problems such as expensive molds, difficult handling, and long delivery due to design change, and is suitable for small-scale mass production. Yes, not suitable for multi-product production. In the dropping sealing method of (2), it is difficult to control the thickness, and drawing must be performed on a large sealing area, resulting in very poor work efficiency. If the viscosity of the resin is not low, the resin cannot be ejected by air pressure, so that a highly reliable resin (generally having a high viscosity) cannot be used. The printing and sealing method (3) is very economical in that it can quickly and simultaneously seal a large number of pieces at the same time and can produce a product having a stable shape. If the viscosity of the resin exceeds 4000 poise, the connection wire may be deformed by the resin pressure.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the above-described printing and sealing method.
An object of the present invention is to provide a printing sealing method that does not cause a problem such as deformation of a connection wire even when using a high-viscosity resin, and has a low coefficient of thermal expansion, low stress, moisture resistance, and heat resistance.
An object of the present invention is to make it possible to seal an electronic component by printing using a resin composition having a high filler content and a high viscosity.

[0005]

The above-mentioned problems in the method of printing and sealing semiconductors and the like are caused by heating an electronic component to be sealed, a sealing material, a printing stencil, a defoaming device, and the like to reduce the viscosity of the resin. The problem was solved by lowering the workability. In the present invention, when an electronic component such as a semiconductor is sealed with a resin by printing, the electronic component and the resin are heated in advance, printing is performed in a heated state, and further, if necessary, in a heated state. The present invention relates to a method for manufacturing an electronic component in which a resin is cured under predetermined curing conditions after defoaming.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a resin for printing and sealing, a resin (composition) which is liquid at room temperature can be used, and those generally used for printing and sealing electronic parts can be used. There is a demand for low thermal expansion coefficient, low stress, moisture resistance, and heat resistance for electronic component encapsulation resins. A resin composition having a high viscosity is used.

In printing and sealing electronic parts such as semiconductors,
If the viscosity of the resin at the time of printing exceeds 4000 poise, for example, if the semiconductor connection wire is long or the wire diameter is small, the wire may be deformed by the pressure of the resin at the time of printing. In addition, the resin is usually defoamed after printing. However, if the viscosity of the resin is high, there is a problem that bubbles are difficult to be removed at the time of defoaming. In a preferred embodiment, the resin is heated in advance to reduce the viscosity to 4000 poise or less to prevent such a problem from occurring. Therefore, the present invention is suitable for a case where a resin (composition) having a viscosity exceeding 4000 poise at room temperature is used for sealing an electronic component.

As a sealing material (resin), epoxy resin,
A resin composition such as a phenol resin, a polyimide resin, a polyamide resin, a polyester resin, a silicone resin, and an acrylic resin can be used. As a composition of epoxy resin, as a compound, epoxy resin, curing agent, accelerator,
A composition containing a coupling agent, an antifoaming agent, a coloring agent, other additives, and a filler can be used.

The epoxy resin is not particularly limited, and any known resin can be used. For example, bisphenol A type, bisphenol F type, bisphenol AD type,
Brominated bisphenol type, biphenyl ether type, phenol novolak type, cresol novolak type, dicyclopentadiene type, naphthalene type, butadiene type, urethane type, silicone type, dicyclic and polyglycidyl ethers, and di and polyglycidyl esters Epoxy resin can be used. In a preferred embodiment, these resins are used alone or in combination of two or more.
The viscosity or melting point of the epoxy resin itself does not matter. In a preferred embodiment, sodium ions are 1 ppm or less and chlorine ions are 1 ppm or less as impurity ions contained in the resin.
ppm or less, and an epoxy resin having a hydrolyzable chlorine of 600 ppm or less is used.

Examples of the curing agent and accelerator include aliphatic, aromatic and alicyclic mono-, di- or polyamines and their modified products, imidazoles and their modified products, dicyandiamide, ureas and their modified products, and amidine compounds. , Acids and acid amides, hydrazine, hydrazides and modified products thereof, phenols and phenol derivatives, tertiary amines, phenol novolak resin, cresol novolak resin, organic phosphine and its derivatives, aliphatic, aromatic, and fatty acids Those selected from cyclic di- or polybasic acid anhydrides can be used alone or in combination of two or more. The viscosity and melting point of these compounds themselves are not particularly important,
In a preferred embodiment, a change over time in the viscosity of the resin composition used as the sealing material, at a temperature at the time of printing and sealing, is selected for a compound that is kept low for 1 hour or more, preferably 2 hours or more, Used in combination as appropriate.

In a preferred embodiment, as the filler, crystalline silica, fused silica, synthetic silica, alumina,
Inorganic powders such as aluminum hydroxide, zirconium, quartz, silicon nitride, and aluminum nitride; elastomer particles such as silicone rubber, acrylic rubber, and butadiene rubber; and powders or short fibers such as polystyrene, polycarbonate, nylon, aramid, and carbon fibers are used. Others
If necessary, an antifoaming agent, a leveling agent, a thixotropic agent,
Various additives such as a coupling agent can be blended. A diluent such as a reactive diluent or a solvent can be added to improve workability. In a preferred embodiment, a diluent that does not cause a significant change in viscosity during printing is selected and used.

In the present invention, electronic components such as semiconductors are sealed with resin by printing. The present invention provides (1) preheating a sealed electronic component, (2) printing a resin while the electronic component is heated, and (3) preheating a sealing resin. (4) Preheating the print mask, (5) Discharging the heated resin on the print mask while heating, (6) Cleaning the sealed parts after printing. It is characterized by defoaming while heating.

According to the present invention, a heating mechanism is newly provided on a sealing resin printing line so that an electronic component to be sealed and a resin used for sealing can be heated in advance and printing can be performed in a heated state. Can be implemented.

FIG. 1 is a schematic view of a printing line for carrying out the present invention. However, the heating method, the tool, and the material are not limited to these, but are merely examples.
The electronic component 1 to be sealed is preheated on a metal heat block 2. Heat block 4 for heating printing table 3
Is used. A band heater 6 is added to the resin supply tank 5 to preheat the resin 7. A film heater 9 is attached to a portion of the print mask 8 that does not interfere with the printing operation.
Further, in the defoamer 10, a heater 11 is embedded in a wall surface to make the inner wall metallic and to heat the inside of the defoamer. The temperature of each heating may be set to a temperature at which the temperature of the sealing resin becomes 4000 poise or less.
Select in the range of 0-200 ° C.

[0015]

In the conventional resin sealing of electronic parts by printing, it is necessary to use a sealing material which is liquid at normal temperature. In general, it is said that a sealing material which is liquid at normal temperature has drawbacks such as poor moisture resistance reliability and poor heat cycleability as compared with a molding material formed by transfer molding. The reason why the moisture resistance reliability is poor is that it is necessary to use an epoxy resin that is liquid at room temperature, and if a liquid curing agent is used at room temperature or a solid curing agent is used, the compounding ratio is slightly reduced and the viscosity of the sealing material is reduced. From a large rise. In addition, the reason why the heat cycleability is inferior is that the thermal expansion coefficients of the sealing material and the semiconductor chip are different, and this is improved by increasing the ratio of a filler such as silica. There is naturally a limit as it increases the viscosity of the stop material.

In the present invention, since the resin is heated in advance, a sealing material which is solid at room temperature can be used. Also,
By appropriately selecting a curing agent, an accelerator, and the like to be mixed with the resin (encapsulant), it is possible to suppress a change with time in viscosity during heating. Can be used. Therefore, according to the present invention, if necessary, the compounding amount of the filler is set to 9 which is the limit at which the resin can act as a binder.
The amount can be increased to nearly 9 wt%, and a highly reliable sealing material can be mass-produced in a short period of time without adding the cost of auxiliary materials, and it is possible to produce electronic parts with productivity and cost merit. .

[0017]

EXAMPLE The following encapsulant materials were mixed by heating to 80 ° C., and the mixture was stirred under vacuum at 80 ° C. for 1 hour with a planetary mixer, and then cooled to 50 ° C. to obtain a curing accelerator (HX-374).
6 (Asahi Kasei Kogyo Co., Ltd.) was added, and the mixture was further stirred under vacuum for 15 minutes to obtain a sealing material A.

Bisphenol type epoxy resin as raw material of sealing material : Epicoat 828 (Yuka Shell Epoxy Co., Ltd.) 100 parts Acid anhydride curing agent: HN-2200 (Hitachi Chemical Industry Co., Ltd.) 90 parts Color pigment: carbon black 1 Part Silane coupling agent: A-187 (Nippon Unicar Co., Ltd.) 10 parts Filler: silica (average particle size: 20 μm) 1760 parts.

This sealing material A has a viscosity of 12,000 poise at 23 ° C. (normal temperature), 3000 poise at 40 ° C., and 1200 poise at 60 ° C. Pot life is 20 days at 23 ° C, 3 days at 40 ° C, 6 days at 60 ° C
It was time.

A 6 mm × 6 mm silicon chip having a thickness of 450 μm is die-bonded on a glass-epoxy circuit board, and the silicon chip and the circuit board are wire-bonded with a gold wire and electrically connected to each other to obtain a test piece (electronic component). The following resin sealing was performed by the printing line of FIG. About the obtained electronic parts,
The presence or absence of wire flow, the presence or absence of air bubbles, the heat cycle property (-40 ° C to + 150 ° C), and the moisture resistance life (85 ° C /
85% RH). Table 1 shows the results.

Example 1 A sealing material A, a printing mask, a substrate on which a semiconductor chip was mounted, and a defoamer were heated to 60 ° C. to perform printing and sealing.

Example 2 A sealing material A, a printing mask, a substrate on which a semiconductor chip was mounted, and a defoamer were heated to 40 ° C. to perform printing and sealing.

COMPARATIVE EXAMPLE 1 A sealing material A, a printing mask, a substrate on which a semiconductor chip was mounted, and a defoamer were subjected to printing and sealing at room temperature without heating.

[0024]

[Table 1] Example 1 Example 2 Comparative Example 1 Wire flow None None Occurrence Bubble residue None None Many Heat cycle property (cycle) 1000 or more 1000 or more and less than 20 Moisture resistance life test 1000 hours 780 hours 230 hours

[0025]

According to the present invention, since resin and the like are pre-heated, printing and sealing of electronic parts can be carried out at a normal temperature because the viscosity is high although the sealing material is extremely reliable. The resin that has been difficult to stop can be used without hindering the workability, so that more reliable electronic components can be mass-produced at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic view of a printing line used for carrying out the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tsuneichi Hashimoto 2339-7 Oshinohara, Yasu-cho, Yasu-gun, Shiga Prefecture (56) References JP-A-5-114620 (JP, A) (58) Fields investigated ( Int.Cl. ⁶ , DB name) H01L 21/56 H01L 23/28-23/30 H01C 1/01

Claims (5)

(57) [Claims] 1. When an electronic component such as a semiconductor is sealed with a resin by printing, the electronic component and the resin are heated in advance,
A method for producing an electronic component in which printing is performed in a heated state, and defoaming is performed in a heated state as necessary, and then the resin is cured under predetermined curing conditions. 2. An electronic component such as a semiconductor is printed with a resin.
When sealing, heat the electronic components and resin in advance,
Printing is performed in a heated state, and further heated
After defoaming, cure the resin under the prescribed curing conditions
Manufacturing method of electronic components. 3. a resin is a resin composition which does not cause changes in viscosity during the heating printing process, the electronic component according to claim 1 or 2 in viscosity to a state of pre-resin can print operations heated to decrease Production method. 4. A resin having a viscosity of 4 at room temperature (23 ° C.).
The resin according to any one of claims 1 to 3, which uses a resin exceeding 000 poise
A method for manufacturing an electronic component according to any of the claims. 5. The method according to claim 5, wherein each heating temperature is set to a value of 4000
5. The method according to claim 1, wherein the temperature is set to be equal to or less than the size.
The method for producing an electronic component according to claim 1.