JP4200090B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device in which a semiconductor element is mounted by flip chip connection.

  Flip chip connection is a method in which the active element surface of a semiconductor element is connected to a substrate. As an example, a semiconductor element having gold stud bumps on an electrode is soldered to a connection electrode provided on the substrate, and then the semiconductor A method of mounting an underfill resin between an element and a substrate is known. However, in the case of the method of underfilling after soldering the semiconductor element, the semiconductor element is filled until the underfill resin is filled between the semiconductor element and the substrate and the underfill resin is cured in the heating furnace. Since it is supported only by the solder joint part, the arrangement interval of the electrodes of the semiconductor element is wide, the area of the connection electrode of the substrate can be increased, and there is no problem in the case of the semiconductor element in which the joint part has sufficient strength by solder joint. In the case of a semiconductor element in which the arrangement interval of the electrodes of the semiconductor element is narrow, the area of the connection electrode of the board is reduced, and the mechanical strength of the solder joint cannot be sufficiently obtained, the heat between the board and the semiconductor element There is a problem that cracks are formed in the solder joint due to stress or mechanical impact during transportation.

For this reason, before bonding the semiconductor element to the substrate, underfill resin is applied to the substrate, the stud bump and the connection electrode are aligned, and the semiconductor element is pressurized and heated to melt the solder. At the same time, there is a method in which the underfill resin is cured and mounted (see, for example, Patent Documents 1 and 2).
6 and 7 show a process in which an underfill resin is previously applied to a substrate and a semiconductor element is mounted by flip chip connection. FIG. 6A shows a semiconductor element 10 mounted on a substrate, and an aluminum pad 12 is formed on an electrode terminal formation surface. FIG. 6B shows a state in which stud bumps 14 are formed on the pads 12 of the semiconductor element 10. The stud bump 14 is formed by bonding a gold wire with a stud bump bonder.

  6C to 6E show the configuration of the substrate 16 on which the semiconductor element 10 is mounted. FIG. 6C shows a state in which connection electrodes (copper pads) 18 are formed on the substrate 16 made of a printed circuit board or the like in accordance with the arrangement of the stud bumps 14. Next, FIG. 6D shows a state where the surface of the connection electrode 18 is covered with the solder 20. For the solder 20, for example, Sn-Ag solder is used. The thickness t of the solder 20 is 5 to 25 μm. Next, FIG. 6E shows a state where the underfill resin 22 is dropped onto the mounting position of the semiconductor element 10 on the substrate 16.

  FIG. 7 shows a process of setting the substrate 16 coated with the underfill resin 22 on a flip chip bonder and flip-chip connecting the semiconductor element 10 to the substrate 16. FIG. 7A shows a state in which the substrate 16 is set on the substrate stage 24 of the flip chip bonder, the semiconductor element 10 is sucked by the suction tool 26, and the connection electrode 18 and the stud bump 14 of the substrate 16 are aligned. is there. The suction tool 26 is heated to a temperature higher than the melting point of the solder in order to melt the solder 20 covering the connection electrode 18. Since the melting point of Sn—Ag solder is 221 ° C., the suction tool 26 is heated to about 250 ° C. to 350 ° C. in this case.

FIG. 7B shows a process in which the semiconductor element 10 is pressed against the substrate 16 by the suction tool 26, the solder 20 is melted and bonded, and the underfill resin 22 is cured together. The underfill resin 22 is spread and filled between the semiconductor element 10 and the substrate 16 to seal the joint between the stud bump 14 and the connection electrode 18. In FIG. 7B, the solder 20 is melted by holding the applied pressure of about 0.5 to 5 g per bump for about 5 to 10 seconds to bond the stud bump 14 to the connection electrode 18, and the underfill resin. 22 is cured. The solder 20 melts in about 1 to 2 seconds, but the suction tool 26 is held for about 5 to 10 seconds because the underfill resin 22 is heated and cured. After the underfill resin 22 is cured, the solder 20 is cooled below the melting point and solidified by separating the suction tool 26 from the semiconductor element 10. FIG. 7C shows a semiconductor device in which the underfill resin 22 is cured and the semiconductor element 10 is flip-chip connected to the substrate 16.
JP 2000-58597 A Japanese Patent Laid-Open No. 2000-10082 JP 2000-21935 A JP 2000-101013 A

  As described above, the method of applying the underfill resin 22 to the substrate 16 in advance and connecting the semiconductor element 10 to the flip chip connection reduces the distance between the electrodes of the semiconductor element 10, and a sufficient machine depending on the solder bonding at the time of flip chip connection. For products in which the desired strength is not obtained, there is an advantage that the joint portion is reinforced by the underfill resin 22 and the problem that a crack occurs in the joint portion can be solved. However, when flip chip connection is performed only by solder bonding, the connection can be made in 1 to 2 seconds, whereas the semiconductor element 10 must be held for about 5 to 10 seconds in order to cure the underfill resin 22. There is a problem that it takes a long time to connect.

In addition, when a single type of semiconductor element is flip-chip connected to a substrate, or even when a plurality of semiconductor elements are mounted on a substrate, if only one semiconductor element is mounted by flip-chip connection, the semiconductor What is necessary is just to mount by the method convenient as a mounting method of an element.
However, when mounting a plurality of semiconductor elements on one substrate, for example, when mounting a semiconductor element such as a microprocessor with a very fine electrode arrangement and a semiconductor element such as a memory that does not require fine connections. However, it is necessary to work by changing the mounting method of the semiconductor element, for example, applying underfill resin 22 to the substrate in advance for one and flip-chip connection, and under-filling the other after flip-chip connection.

  Thus, even when a semiconductor element is mounted by flip chip connection, if the method is different, if a mounting method is individually selected for each semiconductor element, a bonder must be prepared for each. This makes it difficult to balance the production line. On the other hand, if a method for mounting a semiconductor element by pre-applying an underfill resin to a substrate in a common bonder is used, a semiconductor element having sufficient bonding strength only by solder bonding may be mounted. In order to cure the underfill resin, it takes a long bonding time, and the production efficiency is lowered. On the other hand, when solder bonding is first performed and underfill is used as a post-process, for a semiconductor element having a fine electrode interval, the solder joint alone has sufficient mechanical strength until the underfill resin is cured. There is a problem that it will not.

  Therefore, the present invention has been made to solve these problems, and the object of the present invention is to mount even when semiconductor elements having different preferable mounting methods by flip chip connection are mixed in the same substrate. It is an object of the present invention to provide a method for manufacturing a semiconductor device that can be used in a unified manner and enables efficient manufacturing of the semiconductor device.

The present invention has the following configuration in order to achieve the above object.
That is, the first semiconductor element and the second semiconductor element are flip-chip connected to the substrate by solder bonding, and an underfill resin is filled between the substrate, the first semiconductor element, and the second semiconductor element. In the method for manufacturing a semiconductor device, underfill resin is applied to a mounting position of the substrate on which all of the first and second semiconductor elements are mounted, and the first semiconductor element is applied to the substrate. Without being cured the underfill resin is soldered and mounted on the substrate, the second semiconductor element is soldered to the substrate and the underfill resin is cured and mounted on the substrate, After mounting the first semiconductor element and the second semiconductor element on the substrate, heating the entire substrate on which the first and second semiconductor elements are mounted, Characterized in that curing the underfill resin in the first semiconductor device.

Also, the first semiconductor element and the second semiconductor element, which stud bumps are formed on the electrode, the substrate connecting electrode is disposed in accordance with the arrangement of the stud bump, connection electrodes The surface of the solder is coated with solder, the solder is melted, and the stud bump and the connection electrode are joined by solder.
Further, the first semiconductor element and the second semiconductor element are supported by a suction tool of a flip chip bonder, the suction tool is heated to a temperature higher than the melting point of the solder, and the first semiconductor element is attached to the suction tool. While pressurizing the substrate with a tool and soldering to the substrate without curing the underfill resin, pressurizing and heating the second semiconductor element to the substrate with the suction tool and soldering to the substrate The underfill resin is cured.

  According to the method for manufacturing a semiconductor device according to the present invention, a semiconductor device can be mounted on a substrate using a mounting device in common for semiconductor elements having different mounting forms, and the most efficient according to the semiconductor element. Bonding is possible, and the overall production efficiency can be improved. Further, the semiconductor element can be mounted while ensuring the bonding strength between the semiconductor element and the substrate, and a highly reliable semiconductor device can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
1 to 5 are explanatory views showing steps of manufacturing a semiconductor device by the method of manufacturing a semiconductor device according to the present invention.
In the semiconductor device manufacturing method of this embodiment, when a semiconductor element is mounted on a substrate by flip-chip connection, the solder joint has sufficient bonding strength, and therefore, underfill resin is filled after flip-chip connection. The semiconductor element (first semiconductor element) that can be mounted by this method and a semiconductor element that is prone to problems such as cracks in the solder joints due to a narrow electrode interval and the like. The flip chip connection method is applied to a case where a suitable semiconductor element (second semiconductor element) is mixed and mounted on the same substrate.

  In general, when the electrode interval of the semiconductor element is wide, the area of the connection electrode of the substrate can be increased, the amount of solder of the connection electrode can be increased, and the solder joint can obtain sufficient mechanical strength. it can. On the other hand, if the electrode interval of the semiconductor element is narrow, the area of the connection electrode of the substrate is reduced accordingly, the amount of solder of the connection electrode is reduced, and the mechanical strength of the solder joint becomes insufficient.

As a semiconductor element in which the solder joint has a required mechanical strength, for example, a memory element has a wide interval between electrodes and can be mounted using a large-diameter stud bump. One having a bonding strength or one having a small semiconductor element in which a thermal stress generated between the semiconductor element and the substrate is small and a stress that breaks the bonded portion does not act.
In addition, as a semiconductor element that needs to be coated with an underfill resin in advance and hardened at the same time as soldering and reinforced with the underfill resin, electrodes such as a microprocessor are arranged at extremely fine intervals. In order to correspond to this electrode, the area of the connection electrode of the substrate is reduced, and a sufficient mechanical strength cannot be obtained by soldering the stud bump and the connection electrode.
In addition to the thermal stress, the mechanical external force acting on the semiconductor element includes a mechanical impact acting on the semiconductor element or the substrate during handling such as transportation.

1 to 5 show an example in which semiconductor elements having different mounting methods are mounted one by one on the substrate 16 for explanation. That is, of the two semiconductor elements to be mounted on the substrate, the first semiconductor element 10a is a semiconductor element to which a method in which the semiconductor element is solder-bonded to the substrate by flip-chip connection and then underfilled can be applied. The second semiconductor element 10b is a semiconductor element that applies a method in which the underfill resin is cured and mounted at the same time as the solder bonding (without the underfill resin being cured). The underfill resin is cured and needs to be reinforced with the underfill resin).
FIG. 1 shows a substrate 16 on which mounting regions A and B for mounting the first semiconductor element 10a and the second semiconductor element 10b are formed. The mounting area A is an area for mounting the first semiconductor element 10a, and the mounting area B is an area for mounting the second semiconductor element 10b.

  A connection electrode 18 is formed on the substrate 16 in accordance with the arrangement position of the pad 12 (stud bump 14) formed on the first and second semiconductor elements 10a and 10b, and the surface of the connection electrode 18 is soldered. 20 is coated. The structure of the stud bumps 14 formed on the first and second semiconductor elements 10a and 10b, the connection electrodes 18 formed on the substrate 16, and the solder 20 will be described by the conventional flip chip connection shown in FIGS. This is similar to the case where the semiconductor element 10 is mounted.

FIG. 1 shows a sufficient amount to fill the space between the first and second semiconductor elements 10a, 10b and the substrate 16 in the region of the substrate 16 where the first semiconductor element 10a and the second semiconductor element 10b are mounted. The state which dripped underfill resin 22 is shown. The underfill resin 22 is a thermosetting resin in which silica is added to an epoxy resin.
In the semiconductor device manufacturing method according to the present embodiment, the underfill resin 22 is applied to the substrate 16 in advance also in the region where the first semiconductor element 10a to which the underfilling method can be applied after the semiconductor elements are joined by soldering. . That is, first, a required amount of underfill resin 22 is applied to all mounting positions on the substrate 16 where the first and second semiconductor elements 10a and 10b are mounted.

Next, the substrate 16 coated with the underfill resin 22 is set on the substrate stage 24 of the flip chip bonder, and the first semiconductor element 10a is first aligned with the mounting position of the substrate 16 and soldered (see FIG. 2).
An adsorption tool 26 adsorbs and supports the first semiconductor element 10a. The suction tool 26 is heated to a temperature higher than the melting temperature of the solder 20 in order to melt the solder 20 covering the surface of the connection electrode 18 and solder the first semiconductor element 10a. As described above, when Sn—Ag solder is used as the solder 20, since the melting point of the solder is 221 ° C., the suction tool 26 is heated to about 250 ° C. to 350 ° C. The substrate stage 24 may be slightly heated, but is set to a temperature (about 50 ° C. to 150 ° C.) at which the underfill resin 22 does not start to cure.

FIG. 3 shows that the first semiconductor element 10 a is supported by the suction tool 26 and pressed against the substrate 16, and the solder bump 20 is melted and the stud bump 14 provided on the first semiconductor element 10 a is used as the connection electrode 18. Shows the state of soldering. Bonding conditions for the first semiconductor element 10a are a pressure of 0.5 to 5 g per bump and a bonding time of 1 to 2 seconds.
After the first semiconductor element 10a is pressed by the suction tool 26 for 1 to 2 seconds to melt the solder 20, the suction tool 26 is cooled to a melting temperature of the solder or lower (220 ° C. or lower in the embodiment), and the solder 20 is removed. Solidify.

  The operation of soldering the first semiconductor element 10a to the substrate 16 is an operation of melting the solder 20 and bonding the stud bump 14 to the connection electrode 18, and the time during which the first semiconductor element 10a is pressurized is It may be about 1 to 2 seconds. As shown in FIG. 3, the underfill resin 22 a fills the space between the first semiconductor element 10 a and the substrate 16 and seals the joint portion between the stud bump 14 and the connection electrode 18. In this case, the underfill resin 22a is heated only slightly to increase the viscosity and is not cured.

The first semiconductor element 10a has a wide electrode interval, can take a large area of the connection electrode 18 of the substrate 16, has a sufficiently large amount of solder at the joint, and even if the underfill resin 22a is not cured, only the solder joint can be used. The substrate 16 is mounted with sufficient mechanical strength.
FIG. 3 shows a state in which one first semiconductor element 10a is solder-bonded on the substrate 16, but in the case where other semiconductor elements of the same type or the same type as the first semiconductor element 10a are mounted on the substrate 16. These semiconductor elements are mounted on the substrate 16 by the same method as described above.

After the first semiconductor element 10 a is flip-chip connected to the substrate 16, the second semiconductor element 10 b is mounted on the substrate 16.
FIG. 4 shows a state where the second semiconductor element 10 b is mounted on the substrate 16. The second semiconductor element 10 b is sucked and supported by the suction tool 26, the second semiconductor element 10 b is aligned with the mounting position on the substrate 16, and the second semiconductor element 10 b is directed to the substrate 16 by the suction tool 26. Press to bond.

The suction tool 26 is heated to a temperature equal to or higher than the temperature at which the solder 20 melts (about 250 ° C. to 350 ° C.) in order to melt the solder 20.
When bonding the second semiconductor element 10b using the suction tool 26, the underfill resin 22b is cured simultaneously with the solder bonding. Therefore, it is necessary to set the bonding condition by the suction tool 26 to a condition in which the solder 20 is melted and the stud bump 14 is soldered to the connection electrode 18 and the underfill resin 22b is thermally cured.
In the present embodiment, as the bonding conditions for the second semiconductor element 10b, the pressing force per bump is 0.5 to 5 g, and the pressure holding time is 6 to 10 seconds. Accordingly, the underfill resin 22 can be cured while the second semiconductor element 10b is being pressed by the suction tool 26.

When other semiconductor elements of the same type or the same type as the second semiconductor element 10b are mounted on the substrate 16, the stud bumps 14 are soldered to the connection electrodes 18 as described above, and the underfill resin 22b is thermoset. It is mounted in such a way.
Note that, by slightly heating the substrate stage 24, the underfill resin 22b of the second semiconductor element 10b can be easily cured.

  After the second semiconductor element 10b is mounted on the substrate 16, the substrate on which the first semiconductor element 10a and the second semiconductor element 10b are mounted is moved to a heating furnace, and the underfill resin 22a of the first semiconductor element 10a is removed. Heat cure. Since the underfill resin 22b of the second semiconductor element 10b has already been cured, only the underfill resin 22a of the first semiconductor element 10a is cured in the heating furnace. In the heating furnace, the underfill resin 22a of the first semiconductor element 10a can be cured by holding at 150 ° C. for about 1 hour.

FIG. 5 shows a semiconductor device finally obtained by thermosetting the underfill resin 22a. The first semiconductor element 10a and the second semiconductor element 10b are mounted on the substrate 16 by flip chip connection.
In the present embodiment, the first semiconductor element 10a is first mounted on the substrate 16, and then the second semiconductor element 10b is mounted. However, the order of mounting the semiconductor elements is not limited to this order. Further, when a plurality of first and second semiconductor elements 10a and 10b are mounted on the substrate 16, the mounting order can be arbitrarily set, and the mounting order of the first and second semiconductor elements 10a and 10b is mixed. It is also possible to install it in the form of

  According to the method for manufacturing a semiconductor device of this embodiment, even when semiconductor elements having different mounting forms in flip chip connection are mixed on the same substrate, a common flip chip bonder is used as a manufacturing line. A semiconductor element can be mounted, which makes it possible to configure the production line without complicating it. In addition, it is possible to mount semiconductor elements with sufficient mechanical strength in the solder joints only by soldering time and by efficiently curing the underfill resin in a later process. For semiconductor elements that do not have sufficient mechanical strength, the solder joints are securely protected and mounted at the same time by flipping the underfill resin during flip chip connection. Therefore, it is possible to prevent the occurrence of cracks in the solder joints and to mount semiconductor elements by flip chip connection with high reliability.

According to the semiconductor device manufacturing method of the present embodiment, when semiconductor elements having different mounting methods by flip chip connection are mixed and mounted on the same substrate, flip chip bonders are individually prepared according to the mounting method Compared to this, the configuration of the production line is simplified, the most efficient bonding according to the semiconductor element is possible, and the overall production efficiency can be improved.
Also, since bonding is performed under the condition that the mechanical strength of the joint between the semiconductor element and the substrate is sufficiently ensured according to the semiconductor element, the thermal stress generated between the semiconductor element and the substrate and the machine during handling during the manufacturing process It is possible to prevent a problem that the joint portion between the semiconductor element and the substrate is broken due to a mechanical impact or the like, increase the yield, and provide a highly reliable semiconductor device.

It is explanatory drawing which shows the state which apply | coated the underfill resin to the board | substrate. It is explanatory drawing which shows the state which mounts the 1st semiconductor element on a board | substrate. It is explanatory drawing which shows the state which mounts the 1st semiconductor element. It is explanatory drawing which shows the state which mounts the 2nd semiconductor element on a board | substrate. It is explanatory drawing which shows the state which mounted the several semiconductor element in the board | substrate. It is explanatory drawing which shows the structure of the semiconductor element and board | substrate which are used by flip chip connection. It is explanatory drawing which shows the method of flip-chip-connecting a semiconductor element to a board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor element 10a 1st semiconductor element 10b 2nd semiconductor element 12 Pad 14 Stud bump 16 Substrate 18 Connection electrode 20 Support and solder 22 Underfill resin 24 Substrate stage 26 Adsorption tool

Claims (3)

A semiconductor device in which a first semiconductor element and a second semiconductor element are flip-chip connected to a substrate by solder bonding, and an underfill resin is filled between the substrate, the first semiconductor element, and the second semiconductor element In the manufacturing method of
Applying underfill resin to the mounting position of the substrate on which all the first and second semiconductor elements are mounted;
For the first semiconductor element, it is mounted by soldering to the substrate without curing the underfill resin applied to the substrate,
For the second semiconductor element, it is solder-bonded to the substrate and the underfill resin is cured and mounted on the substrate.
After the first semiconductor element and the second semiconductor element are mounted on the substrate, the entire substrate on which the first and second semiconductor elements are mounted is heated, and an underfill resin for the first semiconductor element A method for manufacturing a semiconductor device, comprising: curing the semiconductor device. In the first semiconductor element and the second semiconductor element, stud bumps are formed on electrodes.
In the substrate, connection electrodes are arranged according to the arrangement of the stud bumps, and the surface of the connection electrodes is coated with solder,
2. The method of manufacturing a semiconductor device according to claim 1 , wherein the solder is melted and the stud bump and the connection electrode are joined by solder . Supporting the first semiconductor element and the second semiconductor element on a suction tool of a flip chip bonder;
Heating the suction tool above the melting point of the solder,
The first semiconductor element is pressed against the substrate by the suction tool and soldered to the substrate without curing the underfill resin,
3. The semiconductor device according to claim 1, wherein the second semiconductor element is pressed and heated on the substrate by the suction tool to be soldered to the substrate and to cure the underfill resin . 4. Production method.

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