KR20010014657A - Compression molding appararus and method of fabricating semiconductor device - Google Patents

Abstract

PURPOSE: To seal a product with a molding resin without accompanying variations in the thickness of the resin layer in simple manner in a compression molding apparatus. CONSTITUTION: This compression molding apparatus seals one surface of a product 30 having a plurality of posts 18 thereon with a molding resin 16. This apparatus comprises an upper mold 42 and a lower mold 44, which are movable toward each other for forming a cavity 46 for locating the product 30 therein. One of the upper and lower molds 42 and 44 has a dummy cavity 48, that surrounds and communicates with the cavity 46.

Description

Manufacturing method of compression molding apparatus and semiconductor device {COMPRESSION MOLDING APPARARUS AND METHOD OF FABRICATING SEMICONDUCTOR DEVICE}

The present invention relates to a compression molding apparatus and a method for manufacturing a semiconductor device, and more particularly to a compression molding apparatus suitable for semiconductor manufacturing for sealing a wafer having a plurality of posts with a molding resin.

Background Art Conventionally, semiconductor packages in which semiconductor chips are sealed with molding resins are known. Semiconductor packages are becoming smaller and smaller, and in recent years, semiconductor packages of almost the same size as semiconductor chips have emerged. Such a semiconductor package is called, for example, a CSP (chip size package).

As one method for producing a CSP, there is a method of forming an integrated circuit, an electrode, or the like on a wafer, sealing the wafer with a molding resin, dicing the wafer after sealing, and separating the semiconductor package into individual semiconductor chips. A post is formed on the surface of the wafer, and the post is connected to an electrode formed on the surface of the wafer. The molding resin is formed to have a thickness almost equal to the height of the post, and the post can be exposed to the surface of the resin and connected to another electronic device. Solder bumps can be formed at the tip of the exposed post.

Molding of the resin is performed using a compression molding apparatus including an upper mold and a lower mold which are movable opposite to each other. A wafer having a plurality of electrode posts is placed in a cavity formed by an upper mold and a lower mold, a certain amount of resin tablet is placed on the wafer, and the lower mold is moved toward the upper mold, for example. The resin tablet is compressed between the upper mold and the lower mold, the resin flows along the upper surface of the wafer while being deformed, and when the lower mold moves to a predetermined position with respect to the upper mold, the upper surface of the wafer is uniformly covered and the thickness of the resin It is supposed to be equal to the height.

When the lower mold moves toward the upper mold, the resin flows along the surface of the wafer, but because of the posts on the surface of the wafer, the resin is subjected to flow resistance, and the path through which the resin flows is not constant. In addition, bubbles are generated from the resin, and the direction in which the bubbles flow is not constant. Therefore, resin may not flow smoothly, and the thickness of resin may change with a position in a wafer.

In addition, there is a variation in the height of the posts of the wafer, and there is a problem that the thickness of the resin is not necessarily the same as the height of the posts when sealed with a certain amount of resin. By the way, conventionally, the height of the post was measured for every wafer, and the amount of resin used was calculated according to the measurement result. Since resin was made to be thrown in as a fixed amount of resin tablet, according to the calculation result, a part of resin tablet was shaved and the amount of resin to be used was adjusted. In this manner, conventionally, troublesome work is required before resin molding.

SUMMARY OF THE INVENTION An object of the present invention is to provide a compression molding apparatus and a method for manufacturing a semiconductor device, in which there is no variation in the thickness of the resin and which can simply encapsulate the wafer with a molding resin.

The compression molding apparatus according to the present invention is a compression molding apparatus for sealing the one surface of a wafer having a plurality of posts on one surface with a molding resin, and has an upper mold and a lower mold movable to face each other to form a cavity in which the wafer is placed. One side of the upper mold and the lower mold surrounds the cavity and has a dummy cavity communicating with the cavity.

According to this configuration, when the lower mold and the upper mold move relative to a predetermined position, the resin flows along the surface of the wafer and flows into the dummy cavity. The generated bubbles also flow into the dummy cavity. Thus, the thickness of the resin does not vary with position in the wafer. In particular, when the resin is introduced into the center of the wafer and the dummy cavity is formed so as to be located along the outer circumference of the wafer, the resin flows from the center of the wafer toward the outer circumference in the radial direction, and the flow of the resin becomes uniform.

Preferably, the dummy cavity extends annularly around the cavity. It is advisable to allow the dummy cavity to extend continuously around the cavity. Preferably, each of the upper mold and the lower mold is a central mold member having an area slightly larger than the area of the wafer, and a peripheral mold member disposed around the central member, and the dummy cavity is an upper mold. And between one central member and the peripheral member of the lower mold. This makes the flow of the resin more uniform, and there is no case where the thickness of the resin varies depending on the position in the wafer.

Preferably, the dummy cavity includes a movable lower member. In this manner, by varying the depth of the dummy cavity, the amount of resin can change the depth of the dummy cavity consistently with the height of the post, and the thickness of the resin can be made equal to the height of the post.

Furthermore, in the method of manufacturing a semiconductor device according to the present invention, the wafer is placed in a mold cavity with the molding resin placed on a wafer having a plurality of posts on one surface thereof, and the molding resin is pressed. And actuating the actuating member of the mold, and further actuating the actuating member such that the molding resin covers the wafer and the excess resin surrounds the cavity and is absorbed by the dummy cavity through the cavity.

1 is a cross-sectional view showing an example of a semiconductor package produced using the compression molding according to the present invention.

FIG. 2 shows a process for manufacturing the semiconductor package of FIG. 1. FIG.

3 is a detailed view of the process of forming the integrated circuit, electrode or post of FIG. 1 on the silicon wafer shown in FIG. 2A;

4 shows a first step of a process of encapsulating a wafer having an electrode post with a molding resin;

FIG. 5 shows a second step of the process of encapsulating a wafer having an electrode post with a molding resin; FIG.

FIG. 6 shows a third step of the process of encapsulating a wafer having an electrode post with a molding resin; FIG.

FIG. 7 shows a fourth step of the process of encapsulating a wafer having an electrode post with a molding resin; FIG.

8 is a cross-sectional view of a compression molding apparatus for sealing a wafer having an electrode post with a molding resin.

9 is a plan view showing a lower mold of the compression molding apparatus of FIG.

10 is a cross-sectional view of the compression molding apparatus of FIG. 8 with varying depths of the dummy cavity.

[Description of the code]

10... Semiconductor package

12... Semiconductor chip

14. electrode

16. Molding resin

18. Post

20... Solder ball

22. Repositioning electrode

30. Silicon wafer

40…. Compression molding machine

42. Top mold

44. Bottom mold

46. Cavity

48. Pile cavity

50... Slit

52... The absence

54. Driving rod

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

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the semiconductor package produced using the semiconductor manufacturing apparatus (including a compression molding apparatus) by this invention. The semiconductor package 10 includes a semiconductor chip 12. The size of the semiconductor package 10 is about the same as the size of the semiconductor chip 12, and this semiconductor package 10 is called a CSP.

The semiconductor package 10 includes a semiconductor chip 12, an integrated circuit (not shown) formed on the semiconductor chip 12, an electrode 14 formed on the semiconductor chip 12 and connected to the integrated circuit, The molding resin 16, the post 18 which extends in the molding resin 16, and is connected to the electrode 14, and the solder ball 20 hold | maintained at the front-end | tip of the post 18 are provided.

The surface of the molding resin 16 and the tip of the post 18 are substantially in the same position. The electrode 14 of the semiconductor chip 12 is rearranged by the rearrangement electrode 22, and the post 18 is connected to the electrode 14 through the rearrangement electrode 22. Therefore, even when the electrode 14 is locally arranged in a part of the semiconductor chip 12, the repositioning electrode 22 can be uniformly distributed in a wide area of the semiconductor chip 12. 24 and 24a are insulating layers.

2A to 2D illustrate a process for manufacturing the semiconductor package 10 of FIG. 1. FIG. 2A shows a process of forming the integrated circuit, electrode 14 or post 18 of FIG. 1 on silicon wafer 30. FIG. 2B shows a process of forming the molding resin 16 and the solder balls 20 of FIG. 1 on the silicon wafer 30. 2C is a diagram illustrating a step of dicing the silicon wafer 30 on which the solder balls 20 are formed into individual semiconductor packages 10. 2D is a diagram illustrating the separated semiconductor package 10. As can be seen in FIG. 2B, in the present invention, the molding resin 16 is formed on the silicon wafer 30.

3 is a detailed view of the process of forming the integrated circuit, electrode 14 or post 18 of FIG. 1 on the silicon wafer 30 shown in FIG. 2A. As shown in FIG. 3A, an integrated circuit or an electrode 14 is formed on the silicon wafer 30, and then an insulating layer 24 is formed on the silicon wafer 30 to expose the electrode 14. (It is also possible to add the insulating layer 24a of FIG. 1). Next, the shield metal layer 32 is formed on the insulating layer 24.

As shown in FIG. 3B, a resist 34 is applied on the shield metal layer 32, and the resist 34 is patterned. Next, the repositioning electrode 22 is formed using the resist 34, and the resist 34 is peeled off. As shown in FIG. 3C, another resist 36 is applied and the resist 36 is patterned. Next, the resist 36 is used to form the post 18. A barrier metal is formed at the tip of the post 18.

As shown in FIG. 3D, the resist 36 is peeled off. As shown in FIG. 3E, the shield metal layer 32 is etched. In this way, the wafer 30 having the electrode posts 18 was prepared.

4 to 7 are views showing the first to fourth processes of the process of sealing the wafer 30 having the electrode posts 18 with a molding resin. 8 and 9 show a compression molding apparatus (semiconductor manufacturing apparatus) for sealing the wafer 30 having the electrode posts 18 of FIGS. 4 to 7 with a molding resin. 8 and 9, the semiconductor manufacturing apparatus (compression molding apparatus) 40 has an upper mold 42 and a lower mold 44 that are movable opposite to each other to form a cavity in which the wafer 30 is disposed.

The upper mold 42 is composed of a central member 42a having an area slightly larger than that of the wafer 30 and a peripheral member 42b disposed around the central member 42a. Similarly, the lower mold 44 is composed of a central member 44a having an area slightly larger than that of the wafer 30 and a peripheral member 44b disposed around the central member 44a. The upper mold 42 and the lower mold 44 form a cavity 46 for placing the wafer 30 therebetween.

In an embodiment, the lower mold 44 is fixedly disposed, and the upper mold 42 is movably disposed toward or away from the lower mold 44. The central member 42a and the peripheral member 42b of the upper mold 42 are movable independently of each other.

The dummy cavity 48 is provided in a continuous annular fashion between the central member 44a and the peripheral member 44b of the lower mold member 44. That is, the dummy cavity 48 is provided in the circular shape around the cavity 46 (FIG. 9). The upper outer periphery of the central member 44a of the lower mold member 44 has an annular protrusion 44c, and the annular protrusion 44c has a plurality of radially arranged slits 50 having an upper opening. The cavity 46 and the dummy cavity 48 communicate at least through the slit 50.

The dummy cavity 48 includes a movable ring-shaped bottom member 52. That is, the dummy cavity 48 is formed by the outer peripheral surface of the central member 44a, the inner peripheral surface of the peripheral member 44b, and the upper surface of the bottom member 52. As shown in FIG. The bottom member 52 is slidable with respect to the outer circumferential surface of the central member 44a and the inner circumferential surface of the peripheral member 44b. The lower part of the bottom member 52 is fixed to the plurality of parallel drive rods 54, and the drive rod 54 is fixed to the drive ring 56. The drive ring 56 is driven through the gear train 60 and the feed screw 62 by a motor 58 such as a servo motor or a step motor. You may drive by hydraulic pressure other than a motor, a spring pressure, etc. Thus, the bottom member 52 is movable in the vertical direction, whereby the depth (and volume) of the dummy cavity 48 is increased or decreased.

By controlling the position of the bottom member 52 of the dummy cavity 48 in accordance with the height of the post 18 of the wafer 30, a resin encapsulation is carried out while absorbing excess resin into the dummy cavity 48 using a certain amount of resin. It is possible to adjust the amount of resin used according to the height of the post 18 of the wafer 30. 8 is a diagram showing a case where the depth (volume) of the dummy cavity 48 is large because the height of the post 18 of the wafer 30 is relatively small and the amount of resin used is small. 10 is a diagram showing a case where the depth (volume) of the dummy cavity 48 is small because the height of the post 18 of the wafer 30 is relatively large and the amount of resin used is large.

In addition, as shown in FIG. 8, the load cell 64 is provided in the drive rod 54, and the pressure in the cavity 46 is detected by detecting the load applied to the drive rod 54. As shown in FIG. When the pressure in the cavity 46 is relatively low, the depth of the dummy cavity 48 becomes small, and when the pressure in the cavity 46 is relatively high, the depth of the dummy cavity 48 becomes large. The motor 58 may be controlled according to the detected value.

In this case, since the depth of the dummy cavity 48 can be controlled automatically, the operation of measuring the height of the post 18 of the wafer 30 can be omitted. In addition, the pressure in the cavity 46 may be detected directly, or the pressure in the cavity 46 may be detected by detecting the torque of the motor 58. Moreover, even if the lower member 52 is not moved as a whole, a part of the lower member 52 may be partially moved to change the volume of the dummy cavity 48.

4 shows a state in which the upper mold 42 is in a position above the lower mold 44. The cavity 46 is open. The wafer 30 having the posts 18 is disposed in the cavity 46, and placed on the surface of the central mold 44a of the lower mold 44. A certain amount of softened resin tablet 66 is placed on the wafer 30, and the film 68 is held on the lower surface of the central die 42a of the upper die. In this state, the upper mold 42 is moved toward the lower mold 44.

5 shows a state in which the upper mold peripheral member 42b is in contact with the peripheral mold member 44b of the lower mold 44. In this state, the drive of the upper mold peripheral member 42b is stopped, and only the upper mold centered member 42a is further moved toward the central mold 42a of the lower mold 44. The distance between the lower surface of the central mold member 42a of the upper mold and the upper surface of the central mold member 42a of the lower mold 44 is smaller than the original thickness of the resin tablet 66, and the resin tablet 66 is compressed, The resin flows along the upper surface of the wafer 30 while being deformed. That is, the resin tablet 66 is initially placed in the center of the wafer 30, compressed and widened toward the periphery of the wafer 30.

6 is a view showing a state in which only the central die 42a of the upper die is further moved toward the central die 42a of the lower die 44. The distance between the lower surface of the central mold member 42a of the upper mold and the upper surface of the central mold member 42a of the lower mold 44 is equal to the sum of the thickness of the wafer 30 and the height of the post 18, and the resin is the wafer 30. It spreads widely around the periphery, and excess resin flows into and absorbs into the dummy cavity 48. The tip of the post 18 of the wafer 30 is in contact with the film 68 held on the lower surface of the upper centered member 42a, and is embedded in the film 68. Here, the drive of the upper centered member 42a is stopped.

In this manner, the resin flows along the surface of the wafer 30 and flows into the dummy cavity 48. The generated bubbles also flow into the dummy cavity 48. Therefore, there is no case where the thickness of the resin varies depending on the position in the wafer 30. In particular, since the resin is introduced into the center of the wafer 30 and the dummy cavity 48 is formed along the outer circumference of the wafer 30, the resin flows from the center of the wafer 30 toward the outer circumference in the radial direction. , The flow of resin becomes uniform.

7 shows a state in which the upper mold 42 is moved to be separated from the lower mold 44. The wafer 30 is easily separated from the lower mold 44, and the film 68 is easily removed from the upper mold 42 with the post 18 of the wafer 30 attached to the resin 16 (66). Are separated. If the amount of the resin on the annular projection 44c is large, it is difficult to separate the wafer 30 from the lower die 44. However, if the slit 50 is provided in the annular projection 44c, the wafer 30 is formed. Is easily separated from the lower mold 44. If the film 68 is not present, the resin 16 (66) filling the post 18 of the wafer 30 adheres to the upper mold 42 and is not easily separated from the upper mold 42. Therefore, it is preferable to use the film 68. Since the film 68 becomes a part of the molding resin which covers the surface of the wafer 30, it is good to adhere to the wafer 30 as it is.

As mentioned above, although the compression molding apparatus which concerns on this invention was demonstrated to an example as a semiconductor manufacturing apparatus, the compression molding apparatus which concerns on this invention is not limited to a semiconductor manufacturing apparatus.

As described above, according to the present invention, there can be obtained a compression molding apparatus and a method for manufacturing a semiconductor device which can be easily sealed with a molding resin without variation in the thickness of the resin.

Claims (5)

A compression molding apparatus for sealing the one surface of a wafer having a plurality of posts on one surface with a molding resin, And an upper mold and a lower mold movable relative to each other to form a cavity for placing a wafer, wherein one of the upper mold and the lower mold has a dummy cavity surrounding and passing through the cavity. The compression molding apparatus as claimed in claim 1, wherein the dummy cavity extends in a continuous annular fashion around the cavity. 2. The mold according to claim 1, wherein each of the upper mold and the lower mold is a central mold member having an area slightly larger than that of a wafer, and a peripheral mold member disposed around the central mold member. And said dummy cavity is provided between said central member and said peripheral member of one of said upper mold and said lower mold. The compression molding apparatus according to claim 1, wherein the dummy cavity includes a movable lower member. The wafer is placed in a mold cavity with the molding resin placed on a wafer having a plurality of posts on one surface, Operating the actuating member of the mold to press the molding resin, And operating the actuating member so that the molding resin covers the wafer and excess resin is absorbed by the dummy cavity surrounding and passing through the cavity.