JP2928755B2 - Electronic component manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic component manufacturing method for forming an electronic component, which is low in cost, has, high reliability and is formed into a prescribed shape. SOLUTION: Holes 24 and 24 for forming dams 30 are provided in a hole plate 20, a semiconductor chip 8 and lead wires 10 are formed in the lower surface 20a of the hole plate 20 and a recessed part 22 is formed in the lower surface 20a in such a way that it does not come into contact with the lead wires 10. The lower surface 20a of the hoe plate 20 is brought into contact with a board 2 or a board circuit 4 to fill a liquid resin 26 in the holes 24 and 24 by printing and the plate 20 is separated from the board 2, whereby the resin 26 filled in the holes 24 and 24 is transferred on the board 2 to form the dams 30.

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 manufacturing an electronic component by sealing a semiconductor chip or the like.

[0002]

2. Description of the Related Art Generally, diodes, transistors,
Semiconductor chips such as ICs (integrated circuits) and LSIs (highly integrated circuits) are sealed using a sealing material such as epoxy resin.
Manufactured as electronic components. The semiconductor chip is mounted directly on a substrate on which a circuit is formed, mounted on a lead frame, mounted on a chip carrier such as an LCC (leadless chip carrier), or in a ball grid array or the like. After being mounted, sealing is performed with an epoxy resin or the like.

A liquid resin is used as a sealing material such as the epoxy resin, and a method of sealing a semiconductor chip includes a dispenser method in which the liquid resin is dropped on the semiconductor chip by a dispenser, and a plurality of holes are formed. There is a method of printing a liquid resin on a semiconductor chip using a stencil.

[0004]

By the way, the liquid resin used in these methods is a thermosetting resin, and the heat at the time of curing lowers the viscosity of the resin, causing the resin to flow and the shape after curing. Has a characteristic that the outer peripheral portion is wider than the shape immediately after sealing (before curing). When using a liquid resin, in order to prevent the outer peripheral shape from spreading,
It is considered that it is only necessary to use a resin having a high thixotropy to prevent the resin from flowing, but there are naturally limits to the characteristics and controllability.

In recent years, as high-density mounting on substrates has progressed, the sealing area has been more severely restricted, and standards have been set for the external dimensions of electronic components. In order to form an electronic component in a predetermined area or to form an electronic component in a predetermined size, it is necessary to form a dam for preventing the flow of the liquid resin around the outer periphery of the sealing area. This dam is usually formed on a substrate before mounting a semiconductor chip.

[0006] The above dam is formed by drawing a silicone resin with a dispenser and then hardening by applying heat, or exposing using a mask on which a photosensitive film is stuck on a substrate and the shape of the dam is drawn. It is formed by removing an unexposed portion by drawing, or by drawing an ultraviolet curable resin with a dispenser and curing it with ultraviolet light. When the dam is formed by the above method, the cost of the substrate increases due to the formation of the dam, poor connection of the wire bond due to contamination of the connection terminal portion due to bleeding of the dam material at the time of mounting the semiconductor element, the lack of the substrate during transportation of the substrate, and the like. There is a problem of itself, and after the semiconductor chip is sealed, there is a problem such as a decrease in reliability (peeling or cracking) due to a difference between a sealing resin of the semiconductor chip and a material of the dam.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing an electronic component for forming an electronic component having a predetermined shape at low cost and high reliability. And

[0008]

In order to solve the above problems SUMMARY OF THE INVENTION The invention of claim 1, wherein the semiconductor element is mounted Tei
Forming a dam by printing a liquid resin using a stencil dam formed around the semiconductor element that a substrate, wherein
After forming the dam, a step of printing a liquid resin using a sealing stencil inside the dam to seal the semiconductor element is provided. According to a second aspect of the present invention, in the method for manufacturing an electronic component according to the first aspect, the liquid resin for sealing the semiconductor element is printed using the same liquid resin as the liquid resin for forming the dam. It is characterized by.
According to a third aspect of the present invention, in the method of manufacturing an electronic component according to the first aspect, the dam is formed by contacting a dam forming stencil having a concave portion at a position corresponding to the semiconductor element with the substrate. It is characterized by that. According to a fourth aspect of the present invention, in the method for manufacturing an electronic component according to the first aspect,
The semiconductor element is sealed by bringing a sealing stencil having a recess formed at a position corresponding to the dam into contact with the substrate. According to a fifth aspect of the present invention, there is provided the method of manufacturing an electronic component according to the first aspect, further comprising a step of curing the liquid resin sealing the dam and the semiconductor element after printing. According to a sixth aspect of the present invention, in the method of manufacturing an electronic component according to the first aspect, a substrate circuit is formed on the substrate, and the dam electrically connects the semiconductor element and the substrate circuit. It is characterized by being formed later.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a cross-sectional view of a substrate on which a semiconductor chip (semiconductor element) to be sealed is mounted. In FIG. 2, reference numeral 2 denotes a substrate, the material of which is an organic material such as glass or epoxy, ceramic, glass or the like.
On the upper surface of the substrate 2, a substrate circuit 4 is formed. When the electronic component has a lead wire, a metal, a lead frame, or the like is used instead of the substrate 2.

A semiconductor chip 8 is adhered on the substrate circuit 4 by an adhesive 6, and the semiconductor chip 8 and the substrate circuit 4 are electrically connected by lead wires 10, 10. Usually, gold wires or aluminum wires are used for the lead wires 10, but when the active surface is disposed on the lower surface like a flip chip, the semiconductor chips are formed by bump bonding instead of the lead wires 10, 10. 8 and the substrate circuit 4 are electrically connected. The semiconductor chip 8 is shown in FIG.
Although only one is shown, a plurality of semiconductor chips 8 are bonded on the substrate 2.

A method for manufacturing an electronic component according to one embodiment of the present invention includes the steps of: forming a dam around a semiconductor chip 8;
The method is roughly divided into a step of sealing the semiconductor chip 8. First,
A method for forming a dam around the semiconductor chip 8, which is the first step of the method for manufacturing an electronic component according to one embodiment of the present invention, will be described. FIG. 1 is a sectional view showing a first step of a method for manufacturing an electronic component according to one embodiment of the present invention. In FIG. 1, the same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, reference numeral 20 denotes a stencil for printing and forming a dam (a stencil for forming a dam).
The recesses 22 according to the position where the semiconductor chip 8 is arranged.
Are formed. The concave portion 22 may be damaged when the stencil 20 contacts the semiconductor chip 8 or the lead wires 10 when forming the dam, or may be used for electrical connection between the lead wires 10 and the semiconductor chip 8 or substrate circuit. 4 and lead 1
This is for preventing the electrical connection with 0 and 10 from being disconnected. The concave portion 22 is formed by etching when the stencil 20 is made of metal, or is formed by bonding a metal plate. In the case of a material other than metal, it is formed by cutting or metal molding.

Holes 24 are formed around the recess 22 at the positions where the dams are to be formed. still,
Although only one recess 22 and one hole 24 are shown in FIG. 1, a plurality of stencils 20 are provided at predetermined intervals. Reference numeral 26 denotes a liquid resin for forming a dam, which is dropped on the upper surface 20b of the stencil 20. The liquid resin 26 is made of the same material as the liquid resin used when sealing the semiconductor chip 8 described later. For example, if the liquid resin used for sealing the semiconductor chip 8 is a thermosetting resin, the liquid resin 26 is also a thermosetting resin. Resin is used.

The liquid resin 26 and the semiconductor chip 8
The resin used for sealing is preferably a composition of the same resin and a curable system. However, since the shape of the dam preferably has a smaller cross-sectional area and a higher height, the liquid resin 26 should have a high thixotropic property (2.0 or more, preferably 3.0 or more) and good controllability. Must be used. Reference numeral 28 denotes a squeegee formed in a flat plate shape. The squeegee 28 is provided near the upper surface 20 b of the stencil 20.
It can move along b. The moving direction of the squeegee 28 is set in a direction perpendicular to the surface of the squeegee 28.

In the above configuration, after the position of the concave portion 22 provided in the stencil 20 and the position of the semiconductor chip 8 are matched, that is, after the semiconductor chip 8 is adjusted to be located directly below the stencil 20, the substrate 2 Is brought closer to the stencil 20 or the stencil 20 is brought closer to the substrate 2 to bring the substrate 2 into contact with the stencil 20. Thereafter, the liquid resin 26 is applied to the upper surface 20b of the stencil 20.
(See FIG. 1A).

Next, the squeegee 28 is moved along the stencil 20, and the liquid resin 26 dropped on the upper surface 20b of the stencil 20 is filled into the holes 24, 24 formed in the stencil 20 by filling (FIG. 1 (b) )reference). After the above filling is completed,
The dam 30 is formed by separating the stencil 20 from the substrate 2 and transferring the liquid resin filled in the holes 24, 24 of the stencil 20 onto the substrate 2 or the substrate circuit 4 (see FIG. 1C).

When the above-described step of forming the dam 30 is completed, the process proceeds to a step of sealing the semiconductor chip 8. FIG.
Is a second method for manufacturing an electronic component according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a step, in which parts common to FIG. 1 or FIG. In FIG. 3, reference numeral 50 denotes a stencil (sealing stencil) for printing and sealing the semiconductor chip 8, and a hole 52 is provided at a position corresponding to the semiconductor chip 8. Also, the bottom surface 50a of the stencil 50
The recesses 54 are formed around the hole 52 at positions corresponding to the dam 30. The recesses 54, 54
Is formed so as to be larger than the width of the dam 30, and the depth thereof is formed to be larger than the height of the dam 30. The recesses 54 are provided to prevent the dam 30 from being damaged due to the contact between the stencil 50 and the dam 30.

The recesses 54 are provided in the stencil 20 described above.
As in the case of (see FIG. 1), when the stencil 50 is a metal, it is formed by etching or by bonding a metal plate. In the case of a material other than metal, it is formed by cutting or metal molding. Reference numeral 56 denotes a liquid resin, which is the same curable resin as the dam 30. Reference numeral 58 denotes a squeegee formed in a flat plate shape, which is provided near the upper surface 50b of the stencil 50 and is movable along the upper surface 50b of the stencil 50. The moving direction of the squeegee 58 is set in a direction perpendicular to the surface of the squeegee 58.

In the above configuration, the position of the hole 52 provided in the stencil 50 and the position of the semiconductor chip 8 and the position of the dam 30
After the positions of the recesses 54 and 54 are made to coincide with each other, that is, as shown in FIG. 3, the semiconductor chip 8 is located immediately below the hole 52 of the stencil 50 and the dam 30 is
After adjusting the substrate 2 to be located directly below the stencil 50,
Or the stencil 50 is brought close to the substrate 2 to bring the substrate 2 and the stencil 50 into contact. Thereafter, the liquid resin 56 is dropped on the upper surface 50b of the stencil 50 (see FIG. 3A).

Next, the squeegee 58 is moved along the stencil 50, and the liquid resin 56 dropped on the upper surface 50b of the stencil 50 flows into the holes 52 formed in the stencil 50 to be filled therein (see FIG. 3B). ). After the above filling is completed, the stencil 5
The liquid resin filled in the holes 52 is transferred onto the substrate 2 and the substrate circuit 4 by separating the substrate 0 and the substrate 2 (FIG. 3C).
reference).

When the above steps are completed, the process proceeds to the step of curing the liquid resin. In this step, according to the liquid resin used, curing is performed by applying heat or by irradiating ultraviolet rays. The liquid resin transferred into the dam 30 flows at the time of curing, but is leveled without flowing out of the dam 30 because it is blocked by the dam 30, and is cured together with the dam 30. As the resin of the dam 30 and the liquid resin for sealing the semiconductor chip 8, a resin of the same curing system or a resin having a similar composition is used. It is formed. FIG. 4 is a cross-sectional view illustrating an electronic component manufactured by the method for manufacturing an electronic component according to the embodiment of the present invention. As shown in FIG.
The resin for sealing the semiconductor chip 8 is leveled without flowing out of the dam 30 and is integrated with the dam 30.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventor has determined the durability of an electronic component (hereinafter referred to as a prototype) produced by the method for producing an electronic component according to one embodiment of the present invention and the conventional method for producing an electronic component. The comparison was made with the durability of the electronic components.

First, the semiconductor chip 8 and the like to be sealed shown in FIG. 2 will be described with specific numerical values. As a substrate 2 shown in FIG. 2, a commercially available FR-4 substrate having a thickness of 0.6 mm was used to etch the surface plating to form a substrate circuit 4, and the formed substrate circuit 4 was plated with gold. The semiconductor chip 8 has a thickness of 0.6 mm.
An IC chip having a rectangular outer shape of 0 mm × 10 mm and having an electronic circuit formed thereon was used. This semiconductor chip 8
Is bonded onto the substrate circuit 4 using an adhesive DP-500 (manufactured by Nippon Rec Co., Ltd.), and the lead wires 10 for electrically connecting the substrate circuit 4 and the semiconductor chip 8 have a diameter of 23 μm. A gold wire was used.

The stencil 20 for forming the dam 30 shown in FIG. 1 is a stainless plate having a thickness of 1.2 mm, has a depth of 0.8 mm by etching, and has a square inner periphery. And a recess 22 having a side length of 15 mm is formed.
The holes 24, 24 having a width of 1 mm and a square shape were formed. The stencil 50 for sealing the semiconductor chip 8 shown in FIG. 3 is a stainless plate having a thickness of 1.2 mm, and has a square inner periphery formed by etching.
While forming the hole 52 whose side length is 15 mm,
Square recesses 54, 54 having a depth of 0.8 mm and a width of 0.8 mm were formed around the hole 52.

The electronic component manufactured by the method for manufacturing an electronic component according to one embodiment of the present invention is a thermosetting resin NPR-18 (epoxy resin) as the liquid resin 26 for the dam 30 shown in FIG. A compound NPR-785N having a thermosetting property is used as the liquid resin 56 for encapsulating the semiconductor chip 8.
(Epoxy resin compound: manufactured by Nippon Rec Co., Ltd.) was used.

Further, electronic parts for comparison were prepared.
In Comparative Example 1, an ultraviolet-curable resin NUV-20 (epoxy clearate resin: manufactured by Nippon Lec Co., Ltd.) was drawn by the above-described dispenser, and then cured by irradiating ultraviolet light, and the above-described thermosetting resin NPR-785N was used. Is an electronic component created by dropping the inside of a dam with a dispenser. In Comparative Example 2, a stencil plate in which a hole having a square inner periphery and a side length of 15 mm was formed by etching a stainless steel plate having a thickness of 1.2 mm by etching was used. In Comparative Example 2, the thermosetting resin N
This is an electronic component created by printing PR-785N, and does not form a dam unlike the prototype and the electronic component of Comparative Example 1.

FIG. 5 is a table showing the results of comparison of the outer shape with the prototype described above, Comparative Example 1, and Comparative Example 2. As shown in FIG. 5, the prototype has an outer dimension of 18.2 × 1
An electronic component having a predetermined shape of 8.2 mm, a height substantially equal to the thickness of the stencil described above, and an outer dimension and a height both formed in the predetermined shape is obtained.

On the other hand, in Comparative Example 1, although the outer shape of the electronic component is formed to a substantially predetermined size because it is drawn by the dispenser, it has a drawback that the height control is difficult. That is, the electronic component of Comparative Example 1 cannot be used for applications where the height is limited (for example, a notebook computer). The electronic component of Comparative Example 2 has an outer shape of 20.5 × 21.2 mm, which is far from the desired shape, and is not formed at the desired height. Improper.

FIG. 6 is a table showing the results of comparison of characteristics according to changes in temperature and humidity. The test for the change in temperature and humidity was performed by a heat cycle test, a constant temperature and humidity test, and a PCT (Pressure Cooker Test). The heat cycle test was carried out by setting the temperature to -65 ° C.
The temperature and humidity are set to 80 ° C. and 85%, respectively. The constant temperature and humidity test is a test in which the temperature and humidity are set to 80 ° C. and 85%, respectively. Yes, PCT is prototype, Comparative Example 1
The electronic component of Comparative Example 2 and the electronic component of Comparative Example 2 were placed in a pressure cooker and humidified, and the test was performed under the conditions of a temperature of 121 ° C. and a pressure of 2 atm.

As shown in FIG. 6, the prototype and the electronic component of Comparative Example 2 were 500 deg.
It withstands cycle tests, has a durability of 500 hours in a constant temperature and humidity test, and has a durability of 300 hours for PCT, and has extremely excellent characteristics. However, Comparative Example 2
The electronic component No. could not withstand the test of 200 cycles in the heat cycle test, could not obtain the durability of 300 hours in the constant temperature and humidity test, and could not obtain the durability of PCT even for 100 hours. The durability of the electronic component of Comparative Example 1 is poor because there is a large difference in the characteristics between the resin forming the dam and the resin sealing the semiconductor chip. The electronic component of Comparative Example 1 seals the dam. There is a problem that the resin for use is separated.

FIG. 7 is a table showing the results of the popcorn test. In the popcorn test, the prototype, the electronic component of Comparative Example 1, and the electronic component of Comparative Example 2 were left in a humid environment, and a state in which water vapor was contained in the resin sealing the semiconductor chip, and the popcorn test was rapidly performed. This is a test that gives a great temperature change.
In this popcorn test, level 2 to level 4
The test was conducted for three levels. In this three-stage test, level 2 is the most severe test.

Level 2: Temperature and humidity are 85 ° C., respectively.
A test in which the process of changing the temperature to 220 ° C. in 10 seconds is repeated for 3 cycles after being left for 168 hours in an environment of 60%, and a test in which the temperature and humidity are each 60 ° C. and 30% for 192 hours. And then raise the temperature to 220 for 10 seconds.
A test in which the process of changing the temperature to ℃ is repeated for 3 cycles. Level 4: After leaving for 84 hours in an environment with a temperature and humidity of 60 ° C and 30%, the temperature is raised to 220 ° C in 10 seconds
Test that repeats the process of changing to 3 cycles

As shown in FIG. 7, the prototype is level 2
It was found that the electronic component of Comparative Example 2 had durability up to Level 3, and the electronic component of Comparative Example 1 did not even have Level 4 durability. As described above, the electronic component created by the method for manufacturing an electronic component according to the embodiment of the present invention can have an outer shape formed into a desired shape,
It has been found to have very good durability.

[0034]

As described above, the method for manufacturing an electronic component according to the present invention has an effect that an electronic component having a desired shape can be produced very easily and in large quantities at one time. In addition, the produced electronic component has the above-described effects and has extremely excellent durability, so that it can be used for various applications.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first step of a method for manufacturing an electronic component according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a substrate on which a semiconductor chip to be sealed is mounted.

FIG. 3 is a second view of the method for manufacturing an electronic component according to the embodiment;
It is sectional drawing which shows a process.

FIG. 4 is a cross-sectional view showing the electronic component manufactured by the electronic component manufacturing method according to the embodiment;

FIG. 5 is a table showing a comparison result of an outer shape with a prototype, Comparative Example 1, and Comparative Example 2.

FIG. 6 is a chart showing a comparison result of characteristics according to changes in temperature and humidity.

FIG. 7 is a table showing the results of a popcorn test.

[Explanation of symbols]

 2 substrate 4 substrate circuit 8 semiconductor chip (semiconductor element) 10 lead wire 20 stencil (stencil for dam formation) 22 concave part 26 liquid resin 28 squeegee 30 dam 50 stencil (stencil for sealing) 54 concave part 56 liquid resin 58 squeegee

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Noritaka Oyama 21-1, Ohatacho, Takatsuki-shi, Osaka Charman Corp. 301, Settsu Tomita (72) Inventor Tsuneichi Hashimoto 2339-7 Oshinohara, Yasu-cho, Yasu-gun, Shiga Prefecture (56) References JP-A-58-17646 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/56 H01L 23/28-23/30

Claims (6)

(57) [Claims] A step of printing a liquid resin on a substrate on which a semiconductor element is mounted and using a dam forming stencil around the semiconductor element to form a dam; and after forming the dam, forming a dam. Printing a liquid resin using a sealing stencil inside the dam to seal the semiconductor element. 2. The method according to claim 1, wherein the liquid resin for sealing the semiconductor element is printed by using the same liquid resin as the liquid resin for forming the dam. 3. The electronic component according to claim 1, wherein the dam is formed by contacting a dam forming stencil having a recess at a position corresponding to the semiconductor element with the substrate. Method. 4. The electronic component according to claim 1, wherein the semiconductor element is sealed by bringing a sealing stencil having a recess formed at a position corresponding to the dam into contact with the substrate. Production method. 5. The method according to claim 1, further comprising a step of curing the liquid resin sealing the dam and the semiconductor element after printing. 6. The substrate according to claim 1, wherein a substrate circuit is formed on the substrate, and the dam is formed after the semiconductor element is electrically connected to the substrate circuit.
A method for producing the electronic component described in the above.