JPH09120976A - Semiconductor chip mounting method - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To fill a gap between a semiconductor chip and a circuit board with a resin in a short time, and moreover, to leave bubbles in the gap between the semiconductor chip and the circuit board when the filling of the resin is completed. To realize the mounting method of the semiconductor chip. After mounting a semiconductor chip on a circuit board, a gap G between the semiconductor chip and the circuit board is directly filled with a sealing resin through a through hole. The resist layer 2 is formed on the back surface 27B of the circuit board 20B.
A step portion 200B corresponding to the thickness of 8B is formed, and the sealing resin 40 is dammed by the step portion 200B. When heating and curing the sealing resin 40, the semiconductor chip 10 is heated with a light beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting a semiconductor chip such as a flip chip on a circuit board. More specifically, it relates to a technique of filling a resin for sealing a semiconductor chip into a gap between the semiconductor chip and a circuit board.

[0002]

2. Description of the Related Art As a method of mounting a semiconductor chip on a circuit board, as shown in FIG.
After the chip electrode 12E of E (flip chip) and the wiring electrode 24E of the circuit board 20E are bonded by the solder 30E, the gap GE between the semiconductor chip 10E and the circuit board 20E is sealed for the purpose of protecting the bonded portion. It is filled with the stopping resin 40E. As a method of filling the resin,
Conventionally, the sealing resin 40E is applied along one of the four sides of the semiconductor chip 10E, and the applied sealing resin 40 is applied.
E is a gap GE between the semiconductor chip 10E and the circuit board 20E.
Is used to flow into.

[0003]

However, as in the prior art, the sealing resin 40E applied to the vicinity 18E of the edge of the semiconductor chip 10E is the semiconductor chip 10E and the circuit board 2.
In the method of utilizing flowing into the gap GE with 0E, first, according to the speed at which the sealing resin 40E flows into the gap GE between the semiconductor chip 10E and the circuit board 20E,
The sealing resin 40 is provided in the vicinity of the edge 18E of the semiconductor chip 10E.
Since E is applied, it takes time to fill the sealing resin 40E. In addition, the sealing resin 40E applied to the vicinity 18E of the edge of the semiconductor chip 10E
After wrapping around along the four sides of the semiconductor chip 40E,
Since air flows toward the central portion of the gap GE between the semiconductor chip 10E and the circuit board 20E, air loses its escape area, and there is a problem that bubbles are likely to remain in the central portion of the gap GE.

[0004] In view of the above problems, the object of the present invention is to:
To realize a method for mounting a semiconductor chip that can fill a gap between a semiconductor chip and a circuit board with a resin in a short time and does not leave bubbles in the gap between the semiconductor chip and the circuit substrate when the filling of the resin is completed. Especially.

[0005]

In order to solve the above problems, in the method of mounting a semiconductor chip according to the present invention, a resin filling through hole is formed in the circuit board at substantially the center of the mounting region of the semiconductor chip. After joining the wiring electrode of the circuit board and the chip electrode of the semiconductor chip, a sealing resin is filled from the resin filling through hole, and then the sealing resin is cured. And

In the present invention, it is preferable that the sealing resin is filled until the inside of the resin filling through hole is filled.

In the present invention, the resin filling through hole is, for example, a through hole having a conductive layer on the inner peripheral surface.

In this case, the conductive layer has an extended portion formed in a land shape around the opening edge of the through hole on the surface of the circuit board opposite to the mounting surface of the semiconductor chip. Is preferred. Here, the land-shaped extended portion does not matter whether or not it is used for electrical connection.

In the present invention, the resin filling through hole may be formed as a through hole having no conductive layer on the inner peripheral surface.

In the present invention, on the surface of the circuit board opposite to the mounting surface of the semiconductor chip, around the opening edge of the resin filling hole, the sealing resin filled from the resin filling through hole is filled. It is preferable to form a stepped portion for preventing the above.

The stepped portion can be formed by, for example, a wiring pattern formed on the surface of the circuit board opposite to the surface on which the semiconductor chip is mounted.

Further, the step portion may be formed of a resist layer for covering a wiring pattern formed on the surface of the circuit board opposite to the surface on which the semiconductor chip is mounted.

Further, it is preferable that the step portion is composed of the resist layer and a wiring pattern located on the lower layer side of the resist layer.

In the present invention, when the sealing resin is cured, it is preferable to heat the semiconductor chip with light energy.

[0015]

Embodiments of the present invention will be described with reference to the drawings.

[First Embodiment] FIG. 1 is a sectional view showing a semiconductor chip mounting structure according to a first embodiment of the present invention. FIG.
2A is a rear view of the circuit board showing the vicinity of the through hole of the circuit board used for the mounting structure shown in FIG.
(B) is a step of forming the mounting structure shown in FIG.
Process cross-sectional views showing a state before being filled with a sealing resin, FIG.
(C) is a process sectional view showing a state in the middle of being filled with a sealing resin.

In FIG. 1, a semiconductor chip 10 is a flip chip type, and a plurality of chip electrodes 12 are formed on its active surface 11. The circuit board 20A is
A wiring pattern 22 is formed on a surface 21 (mounting surface of the semiconductor chip 10) on which the semiconductor chip 10 is mounted, which is configured as a glass-epoxy substrate or a ceramic substrate. Although the wiring pattern 22 is covered with the resist layer 23, there is a partially exposed portion, and this exposed portion is the wiring electrode 24 joined by the chip electrode 12 of the semiconductor chip 10 and the solder 30. is there.

In this example, the through-hole 2 is formed in the circuit board 20A at a substantially central portion of the mounting area of the semiconductor chip 10.
5A (through hole for resin filling) is formed.

The copper layer 26A formed on the inner peripheral surface of the through hole 25A is shown in FIG. 2A on the back surface 27A of the circuit board 20A (the surface of the circuit board 20A opposite to the mounting surface of the semiconductor chip 10). As shown in FIG. 2, the land-shaped extension 2 located around the opening edge of the through hole 25A.
It is equipped with 61A. As shown in FIG. 1, the extended portion 261A is in a state of being raised from the periphery by the thickness of the back surface 27A of the circuit board 20A. In addition,
It does not matter whether or not the land-shaped extending portion 261A is used for electrical connection.

A sealing resin 40 is filled between the semiconductor chip 10 and the circuit board 20A. Sealing resin 4
0 spreads outside the position where the chip electrode 12 and the wiring electrode 24 are formed, and the semiconductor chip 10
The gap G between the circuit board 20A and the circuit board 20A is completely filled, and a clean fillet is formed while reaching the side surface portion 13 of the semiconductor chip 10. The sealing resin 40 is also in a state of filling the inside of the through hole 25A. Here, in the gap G between the semiconductor chip 10 and the circuit board 20A and in the through hole 25A, no bubbles remain inside the cured sealing resin 40.

Such a mounting structure is obtained as follows. As shown in FIG. 2B, first, in the mounting area of the semiconductor chip 10, the through hole 2 is formed in a substantially central portion.
The wiring electrode 24 and the chip electrode 12 of the semiconductor chip 10 are bonded by the solder 30 on the circuit board 20A on which 5A is formed.

Next, as shown in FIG. 2 (c), from the through hole 25A of the circuit board 20A toward the gap G between the circuit board 20A and the semiconductor chip 10, as indicated by an arrow A, sealing is performed by a dispenser. The resin 40 for filling is filled.

At this time, the circuit board 20A is not heated, but the semiconductor chip 10 side is heated. In this example, since the light beam L (light energy) is irradiated from the back surface 14 side of the semiconductor chip 10 in this heating, there is no problem in filling the sealing resin 40 and the sealing resin 40 Spreads cleanly.

As a result, the semiconductor chip 10 and the circuit board 2
The sealing resin 40 filled in the gap G with the 0A is heated via the semiconductor chip 10 and flows out toward the outer peripheral side of the semiconductor chip 20. Further, as shown in FIG. 1, the sealing resin 40 spreads to the outside of the position where the chip electrode 12 and the wiring electrode 24 are formed to completely fill the gap G between the semiconductor chip 10 and the circuit board 20A. While filling in, and forming a clean fillet, it reaches the side surface portion 13 of the semiconductor chip 10 and hardens. Further, the sealing resin 40 cures in a state where the inside of the through hole 25A is also filled.

As described above, in this example, after the semiconductor chip 10 is mounted on the circuit board 20A, the gap G between the semiconductor chip 10 and the circuit board 20A is directly filled with the sealing resin 40 from the through hole 25A. Therefore, the sealing resin 40
Filling speed is fast.

Further, since the sealing resin 40 is filled from the through hole 25 facing the substantially center of the semiconductor chip 10, the sealing resin 40 is filled with the semiconductor chip 10 and the circuit board 2.
It spreads from the inside to the outside in the gap G with 0A. Therefore, the semiconductor chip 10 and the circuit board 20A
Since the air in the gap G between and is easily discharged outward, when the sealing resin 40 is completely filled,
No bubbles remain in the gap G between the semiconductor chip 10 and the circuit board 20A.

Further, since the sealing resin 40 is filled so as to fill the through hole 25A, even if light is applied from the back surface 27A side of the circuit board 20A, the light is emitted from the through hole 25A to the active surface of the semiconductor chip 10. Since it does not reach to 11, the semiconductor chip 10 does not malfunction. Also, moisture does not reach the active surface 11 of the semiconductor chip 10 through the through holes 25A. Moreover, through hole 2
Since the copper layer 26A of 5A is provided with the extended portion 261A that is raised by the thickness of the back surface 27A of the circuit board 20A, the amount of the raised resin 261A is the sealing resin 4A.
0 can be formed thick. Therefore, it is possible to more reliably prevent light and moisture from reaching the active surface 11 of the semiconductor chip 10 through the through holes 25A.

[Embodiment 2] FIG. 3 (a) is a sectional view showing a mounting structure according to Embodiment 2 of the present invention, and FIG. 3 (b) is an opening of a through hole formed in the circuit board. It is a back view of the circuit board which expands and shows the vicinity.

Since the mounting structure and the mounting method according to this embodiment and the third and fourth embodiments described below have the same basic structure as that of the first embodiment, the corresponding parts are denoted by the same reference numerals. The detailed description thereof will be omitted.

In FIG. 3A, of the circuit board 20B on which the semiconductor chip 10 is mounted, the semiconductor chip 1
A through hole 25B (through hole for resin filling) is formed in the substantially central portion of the mounting area of 0 as in the first embodiment.

In this example, the copper layer 26B formed on the inner peripheral surface of the through hole 25B has a periphery of the opening edge of the through hole 25B on the back surface 27B of the circuit board 20B, as shown in FIG. 3B. Land-shaped extension 2 located at
61B is provided.

Here, the copper layer 26B extends from the land-shaped extending portion 261B as a wiring pattern 29B on the back surface 27B of the circuit board 20B. This extended portion 261B
Is a rear surface 2 of the circuit board 20B, as shown in FIG.
7B, it is in a state of being raised from the surroundings by the thickness thereof.

Further, on the back surface 27B of the circuit board 20,
A resist layer 28B is formed so as to cover the wiring pattern 29B. However, the resist layer 28B is formed as shown in FIG.
As shown in FIG. 3B, since the inner region of the extended portion 261B is exposed, the resist layer is formed on the extended portion 261B near the opening edge of the through hole 25B as shown in FIG. Step portion 200 corresponding to the thickness of 28B
B is configured.

Also in this example, the gap G between the circuit board 20B and the semiconductor chip 10 is filled with the sealing resin 40, and the chip resin 12 and the wiring electrode 24 are formed in the sealing resin 40. The gap G between the semiconductor chip 10 and the circuit board 20 </ b> B is completely filled in by expanding to the outside of the position where the semiconductor chip 10 reaches the side surface portion 13 of the semiconductor chip 10 while forming a clean fillet.
Further, the sealing resin 40 is in a state of completely filling the inside of the through hole 25B and further covering the extended portion 261B of the copper layer 26B. Here, the semiconductor chip 10 and the circuit board 2
In the gap G with 0B and the inside of the through hole 25B, no bubbles remain inside the cured sealing resin 40.

Such a mounting structure is basically obtained by the same method as that of the first embodiment, as briefly described below. First, the wiring electrode 24 is formed on the circuit board 20B in which the through hole 25B is formed in a substantially central portion of the mounting area of the semiconductor chip 10 and the resist layer 28B is formed on the wiring pattern 29 extending from the through hole 25B. And the chip electrode 12 of the semiconductor chip 10 are joined by the solder 30.

Next, the through hole 25 of the circuit board 20B.
The sealing resin 40 is filled from the dispenser B toward the gap G between the circuit board 20B and the semiconductor chip 10.

At this time, the light beam L is applied to the semiconductor chip 10.
The semiconductor chip 10 is heated by irradiating it from the back surface 14 side.

As a result, the semiconductor chip 10 and the circuit board 2
The sealing resin 40 filled in the gap G from 0B is heated via the semiconductor chip 10 and flows out toward the outer peripheral side of the semiconductor chip 20. Therefore, the sealing resin 40 spreads to the outside of the position where the chip electrode 12 and the wiring electrode 24 are formed to completely fill the gap G between the semiconductor chip 10 and the circuit board 20B and to form a clean fillet. While forming, the side surface portion 1 of the semiconductor chip 10
It cures when it reaches the number 3. In addition, the sealing resin 40
Cures in a state where the inside of the through hole 25B is also filled and the extended portion 261B is covered.

Thus, in this example, after the semiconductor chip 10 is mounted on the circuit board 20B, the gap G between the semiconductor chip 10 and the circuit board 20B is directly filled with the sealing resin 40 from the through hole 25B. Therefore, the sealing resin 40
The filling speed is fast, and no bubbles remain in the gap G between the semiconductor chip 10 and the circuit board 20B.
It has the same effect as.

In addition to this, in this example, the circuit board 20B
On the back surface 27B of the resist layer 2 near the opening edge of the through hole 25B, the resist layer 2 that covers the outer peripheral region of the extension 261B
Since the stepped portion 200B is constituted by 8B, even when the sealing resin 40 is applied to cover the extended portion 261B, the sealing resin 40 is dammed by the stepped portion 200B. Therefore, even when the sealing resin 40 is formed thick to surely prevent light and moisture from reaching the active surface 11 of the water semiconductor chip 10 through the through holes 25B, the sealing resin 40 is There is an advantage that it does not flow to an extra area.

[Embodiment 3] FIG. 4A is a sectional view showing a mounting structure according to Embodiment 3 of the present invention, and FIG. 4B is an opening of a through hole formed in the circuit board. It is a back view of the circuit board which expands and shows the vicinity.

Although the through holes are used as the resin filling through holes in the first and second embodiments, they may be simple through holes as in the present example. That is, also in this example, as shown in FIGS.
In the circuit board 20C on which 0 is mounted, a resin filling hole is formed in a substantially central portion of the mounting area of the semiconductor chip 10, but this hole is usually formed with no copper layer inside. Through hole 25C. Other configurations are substantially the same as those of the first and second embodiments.

Therefore, the semiconductor chip 1 is mounted on the circuit board 20C.
After mounting 0, the sealing resin 40 is directly filled from the through hole 25C into the gap G between the semiconductor chip 10 and the circuit board 20C, so that the filling speed of the sealing resin 40 is fast.
In addition, the same effect as that of the first embodiment is achieved, such as no bubbles remaining in the gap G between the semiconductor chip 10 and the circuit board 20C.

Further, in this example, a resist layer 28C is formed on the back surface 27C of the circuit board 20C so as to cover the wiring pattern (not shown). However, as shown in FIG. 4B, since the resist layer 28C is not formed near the opening edge of the through hole 25C, a step portion 200C corresponding to the thickness of the resist layer 28C is formed there. It is configured. Therefore, as shown in FIG. 4A, even when the through hole 25C is completely covered with the sealing resin 40 and the sealing resin 40 is formed thickly, Step portion 200C formed by the layer 28C
It has the advantage that it does not flow into the extra area because it is dammed down by.

When forming the step portion 200C on the back surface 27C of the circuit board 20C, the resist layer 28C is used.
Instead of the above, as shown in FIG. 4C, a land-shaped wiring pattern 29C that surrounds the opening edge of the through hole 25C with a predetermined distance is used, and a step portion corresponding to the thickness of this wiring pattern 29C is used. 200C may be configured.

[Embodiment 4] FIG. 5A is a sectional view showing a mounting structure according to Embodiment 4 of the present invention, and FIG. 5B is an opening portion of a through hole formed in the circuit board. It is a back view of the circuit board which expands and shows the vicinity.

In the mounting structure of this embodiment, as in the third embodiment, a simple hole is used as the resin filling hole. That is, as shown in FIGS. 5A and 5B, in the circuit board 20D on which the semiconductor chip 10 is mounted, a resin filling hole is formed in a substantially central portion of the mounting region of the semiconductor chip 10. However, this hole is a through hole 25D in which a copper layer is not formed inside. Therefore, the circuit board 20D
After the semiconductor chip 10 is mounted on, the sealing resin 40 is directly filled into the gap G between the semiconductor chip 10 and the circuit board 20D from the through hole 25D, so that the filling speed of the sealing resin 40 is fast, and , Semiconductor chip 10 and circuit board 2
The same effect as that of the first embodiment is achieved, such as no bubbles remaining in the gap G from 0D.

In this example, the back surface 2 of the circuit board 20D is also used.
In 7D, the wiring pattern 29D is formed so as to surround the opening edge of the through hole 25D in a land shape, and by this portion, in the vicinity of the opening edge of the through hole 25D, only the thickness of the wiring pattern 29D rises. There is one step 201D. Further, in this example, on the back surface 27D of the circuit board 20D, the resist layer 28D is formed on the wiring pattern 29D so as to avoid the inside of the first step portion 201D. Therefore, the first step portion 2
A second step portion 202D is formed around 01D so as to be raised by the thickness of the resist layer 28D.

According to the mounting structure having such a configuration, after the semiconductor chip 10 is mounted on the circuit board 20D, the through hole 2 is formed in the gap G between the semiconductor chip 10 and the circuit board 20D.
Since the sealing resin 40 is directly filled from 5D, the filling speed of the sealing resin 40 is fast, and no air bubbles are left in the gap G between the semiconductor chip 10 and the circuit board 20D. Produce an effect.

Further, in this example, the through hole 25D is completely covered with the sealing resin 40, and the wiring pattern 29D near the through hole 25D is sealed on the back surface 27D of the circuit board 20D. By applying the resin 40, the sealing resin 40 can be applied thickly at least by the thickness of the wiring pattern 29D. Therefore, from the side of the back surface 27D of the circuit board 20D, light and moisture pass through the through holes 25D and the active surface 11 of the semiconductor chip 10.
Never reach. Even in this case, the sealing resin 40 has the second step portion 20 formed by the resist layer 28D.
Since it is dammed by 2D, it has an advantage that it does not flow into an extra area. That is, the second step portion 2
In 02D, since the wiring pattern 29D is provided on the lower layer side of the resist layer 28D, the sealing resin 40 can be applied thickly without anxiety by adding the wiring patterns 29D.

In this example, the back surface 2 of the circuit board 20D is used.
7D, the first step portion 201D corresponding to the thickness of the wiring pattern 29D and the second step portion 202D corresponding to the thickness of the resist layer 28D are formed. The sealing resin 40 may be dammed by 201D, and the sealing resin 40 may be used so as to be dammed by the second step portion 202D when there is the sealing resin 40 overcoming it. That is, in this example, the resist layer 28D can be prevented from flowing out to an extra region double.

[0052]

As described above, in the method of mounting a semiconductor chip according to the present invention, the sealing resin is filled through the resin filling through hole formed in the circuit board in the substantially central portion of the mounting area of the semiconductor chip. It has characteristics. Therefore, according to the present invention, the gap between the semiconductor chip and the circuit board is directly filled with the sealing resin from the resin filling through hole, so that the sealing resin is filled at a high speed. Further, since the sealing resin is filled from the hole facing the substantially center of the semiconductor chip, the sealing resin spreads from the inside to the outside in the gap between the semiconductor chip and the circuit board. Therefore, no air bubbles remain in the gap between the semiconductor chip and the circuit board when the sealing resin is completely filled.

When the sealing resin is filled so as to fill the inside of the resin filling through hole, light and moisture cannot reach the active surface of the semiconductor chip from the back surface of the circuit board through the resin filling through hole. The semiconductor chip can be protected.

When a land-like extension from the inside of the through hole is provided around the opening edge of the resin filling through hole on the surface of the circuit board opposite to the mounting surface of the semiconductor chip, this extension is used. The sealing resin can be applied thickly by the thickness of. Therefore, it is possible to more reliably prevent light and moisture from reaching the active surface of the semiconductor chip from the back surface of the circuit board through the resin filling through hole.

When a step portion is formed around the resin filling through hole on the surface of the circuit board opposite to the mounting surface of the semiconductor chip, the sealing resin is filled so as to completely fill the resin filling hole. Since the sealing resin is dammed by the step portion even when filling with, there is an advantage that an extra area is not contaminated by the sealing resin.

In particular, when the step portion is formed of two layers by the resist layer and the wiring pattern, a thick step portion can be formed by that much, so that there is a concern that the extra area is contaminated by the sealing resin. Without having to worry, the sealing resin can be applied thickly without anxiety.

If the semiconductor chip is heated by light energy when the sealing resin is cured, there is an advantage that the sealing resin can be filled and the sealing resin spreads neatly. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing a mounting structure according to a first embodiment of the present invention.

2A is a back view of the circuit board showing the vicinity of a through hole of the circuit board used in the mounting structure shown in FIG. 1 in an enlarged manner, and FIG. 2B is a step of forming the mounting structure shown in FIG. Of these, process cross-sectional views showing a state before being filled with a sealing resin,
(C) is a process of forming the mounting structure shown in FIG.
It is process sectional drawing which shows the state in the middle of filling with sealing resin.

3A is a sectional view showing a mounting structure according to a second embodiment of the present invention, and FIG. 3B is an enlarged view of the vicinity of a through hole of a circuit board used in the mounting structure shown in FIG. 3A. 3 is a rear view of the circuit board shown by FIG.

4A is a cross-sectional view showing a mounting structure according to a third embodiment of the present invention, and FIG. 4B is an enlarged view of the vicinity of a through hole of a circuit board used in the mounting structure shown in FIG. 4A. 4C is a rear view of the circuit board, and FIG. 4C is an enlarged rear view of the circuit board used in the modified example of the mounting structure shown in FIG.

5A is a sectional view showing a mounting structure according to a fourth embodiment of the present invention, and FIG. 5B is an enlarged view of the vicinity of a through hole of a circuit board used in the mounting structure shown in FIG. 5A. 3 is a rear view of the circuit board shown by FIG.

FIG. 6 is a cross-sectional view showing a conventional mounting structure.

[Explanation of symbols]

10 ... Semiconductor chips 20A, 20B, 20C, 20D, 20E ... Circuit boards 25A, 25B ... Through holes (resin filling through holes) 25C, 25D ... Through holes (resin filling through holes) 28B, 28C, 28D ... Resist layer 29B, 29C, 29D ... Wiring pattern 40 ... Encapsulating resin 200B, 200C, 201D, 202D ... Step portion 261A, 261B ... From through hole Extension of copper layer (conductive layer)

Claims (10)

[Claims] 1. A resin filling through hole is formed in a circuit board in a substantially central portion of a mounting area of a semiconductor chip, and a wiring electrode of the circuit board and a chip electrode of the semiconductor chip are bonded to each other. A method of mounting a semiconductor chip, which comprises filling a sealing resin through a filling through hole and then curing the sealing resin. 2. The sealing resin according to claim 1,
A method of mounting a semiconductor chip, which comprises filling the inside of the resin filling through hole until it is filled. 3. The method of mounting a semiconductor chip according to claim 1, wherein the resin filling through hole is a through hole having a conductive layer on an inner peripheral surface thereof. 4. The conductive layer according to claim 3, wherein the conductive layer has an extended portion formed in a land shape around an opening edge of the through hole on a surface of the circuit board opposite to a mounting surface of the semiconductor chip. A method for mounting a semiconductor chip, comprising: 5. The method of mounting a semiconductor chip according to claim 1, wherein the resin filling through hole is a through hole having no conductive layer on an inner peripheral surface thereof. 6. The surface of the circuit board opposite to the mounting surface of the semiconductor chip according to claim 1, wherein the resin filling through hole is filled around the opening edge of the resin filling hole. A method of mounting a semiconductor chip, characterized in that a step portion for stopping the sealing resin is formed. 7. The mounting of a semiconductor chip according to claim 6, wherein the step portion is formed by a wiring pattern formed on a surface of the circuit board opposite to a mounting surface of the semiconductor chip. Method. 8. The resist according to claim 6, wherein the step portion is formed of a resist layer for covering a wiring pattern formed on a surface of the circuit board opposite to a mounting surface of the semiconductor chip. And a method of mounting a semiconductor chip. 9. The method of mounting a semiconductor chip according to claim 8, wherein the step portion is composed of the resist layer and a wiring pattern located below the resist layer. . 10. The method of mounting a semiconductor chip according to claim 1, wherein the semiconductor chip is heated by light energy when the sealing resin is cured.