JP2008147601A - Flip-chip bonding method and semiconductor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device capable of preventing foam remaining in a sealing material in flip chip bonding.
A step of providing a sealing material resin 41 having a function of removing an oxide film on a surface of a bonding metal 30 on a terminal surface of a wiring substrate 10; a bump 11 of a terminal 11 of the wiring substrate 10 and a semiconductor chip 20; After the bonding metal 30 on 21 is arranged opposite to each other, the bonding metal 30 is melted under heating conditions that do not satisfy the curing start conditions of the sealing material resin 41 and then cooled and solidified, and the bonding metal 30 is melted. For a sealing material under a temperature condition that is lower than a predetermined temperature as a curing start condition and softens the sealing material resin 41. A flip-chip bonding method comprising a step of removing voids of the resin 41 and a step of curing the resin for sealing material.
[Selection] Figure 2

Description

  The present invention relates to a flip chip bonding method for bonding a terminal of a semiconductor chip to a terminal of another semiconductor chip or a terminal on a wiring substrate, and a method of manufacturing a semiconductor device using the flip chip bonding method.

  In recent years, many semiconductor devices having a function that cannot be realized by a single chip by combining a plurality of semiconductor chips called system-in-package (hereinafter referred to as SiP) have been proposed. In general, flip chip (hereinafter referred to as FC) bonding is applied to the bonding. Moreover, in such mounting using FC bonding, the periphery of the bonding terminal is sealed with a sealing resin called underfill. As this method, a post-underfill method and a pre-underfill method are known. ing.

  The post-underfill method is a method that is generally used at present. After joining the terminals, a liquid sealing material is injected into the gap between the chips with a sealing material filling device, and the capillary phenomenon is used. Then, a sealing material is injected around the joint terminal, and then the sealing material is cured to seal the joint portion.

  On the other hand, in the first underfill method, before joining the terminals, a predetermined amount of an underfill material that is a sealing material is applied or pasted to a terminal surface provided with terminals of either or both chips, and then the terminals are connected to each other. The chips are arranged so as to face each other so as to be aligned, and terminal bonding and sealing material are cured by heating, pressurization, ultrasonic waves, etc., and FC bonding is performed and the underfill material is cured.

  In the post-underfill method, when a plurality of chips are mounted side by side, a gap between the chips becomes narrow, and it is difficult to secure a sealing material injection space. Also, if the terminal spacing is narrow, the bumps are small, and the connection gap is small, the filler in the sealing material will not flow easily, so when mounting a high-density mounting semiconductor device or a chip with a narrow terminal spacing The first underfill method is advantageous.

  However, the problem with the underfill method is how to perform a solder bonding process and a previously provided underfill material curing process so as not to cause bonding failure between terminals.

  Therefore, after applying a bond (underfill material) containing a curing agent having a melting point lower than the melting point temperature of the solder, the solder is heated above the melting temperature before the bond is completely cured while pressing with a crimping tool. A method has been proposed in which solder is melted and bonded before it is completely cured (see Patent Document 1).

  Also, after applying a bond (underfill material) containing a curing agent with a melting point lower than the melting point temperature of the solder, it is heated while pressing with a crimping tool to start the curing of the bond before the solder bumps melt, Wrapped with a high-viscosity bond, and after reaching the control switching temperature range lower than the soldering temperature melting point temperature, control is performed by switching from the pressure load control to the height control method to prevent short circuit between the electrodes and FC joining A method has been proposed (see Patent Document 2).

  In addition, a film made of a thermosetting resin that is solid at room temperature is attached to the chip as an underfill material, and this is melted at a temperature below the melting point of the solder so that the molten state is maintained when the chip and the wiring board are joined. Then, after electrically connecting the chip and the wiring board, a method of curing the thermosetting resin at a temperature below the melting point of the solder has been proposed (see Patent Document 3).

  In FC bonding by these first underfill methods, bubbles or resin generated by air entrainment when a semiconductor chip coated with a sealing material and a wiring board or semiconductor chip to be bonded to each other are arranged opposite to each other. There is a problem that the reliability of the semiconductor device is impaired due to bubbles generated when exposed to a high temperature. In order to solve such a problem, it has been proposed to perform a defoaming process in the FC joining by the first underfill method (see Patent Document 4), but the FC joining process and the curing process of the underfill material are different. It is performed at the same time, and it is difficult to perform defoaming effectively.

  Also, in FC bonding, a process of removing the oxide film on the surface of the solder with a flux and a process of cleaning the flux after the bonding are necessary. In the underfill method, how to use such an oxide film It may be a problem whether to process it. In order to solve such a problem, a liquid resin composition that is composed of a curing agent having a flux action and an epoxy resin and has excellent electrical insulation and a short sealing time has been proposed (see Patent Document 5). Such a liquid resin composition can be applied to the previous underfill method, but has a short sealing time and cannot solve the problem of bubbles.

JP-A-11-214440 JP-A-11-214438 Japanese Patent No. 3558576 Japanese Patent Laid-Open No. 2004-247531 JP 2001-106770 A

  In view of the above-described circumstances, the present invention is less likely to cause poor bonding in FC bonding by the underfill method, and can be used for narrow terminal intervals, and semiconductors using these narrow terminal interval FC bonding methods An object is to provide a method for manufacturing a device.

  According to a first aspect of the present invention that achieves the above object, a first chip and a second chip made of a semiconductor chip or a wiring substrate are arranged so that terminal surfaces provided with respective terminals are opposed to each other, and at least one terminal is used. In a flip chip bonding method in which the terminals of the first chip and the second chip are bonded to each other through the bonding metal provided, either or both of the terminal surfaces on which the terminals of the first chip and the second chip are provided A step of providing a sealing material resin having an action of removing an oxide film on the surface of the bonding metal, and then facing the first chip and the second chip so that the terminals face each other. After arranging, between the terminals until the bonding metal is cooled and solidified after melting the bonding metal under heating conditions that do not satisfy the curing start condition of the resin for sealing material and after the bonding metal is melted The step of bonding the terminals together so as to apply a certain load, and then the sealing resin under a temperature condition that is lower than a predetermined temperature as the curing start condition and softens the sealing resin There is a flip chip bonding method characterized by comprising a step of removing voids and a step of curing the resin for sealing material.

  According to a second aspect of the present invention, in the flip-chip bonding method according to the first aspect, a heating condition until the solidifying metal is cooled and solidified after melting the bonding metal is equal to or higher than a predetermined temperature that satisfies the curing start condition. However, the flip chip bonding method is characterized in that the heating time is less than the curing start condition.

  According to a third aspect of the present invention, in the flip-chip bonding method according to the first or second aspect, a heating condition until the solidifying metal is cooled and solidified after melting the bonding metal is a temperature of 140 ° C. or higher within 200 seconds. The flip-chip bonding method is characterized in that the heating conditions are as follows.

  According to a fourth aspect of the present invention, in the flip chip bonding method according to any one of the first to third aspects, a sealing material resin is provided on a terminal surface of either or both of the first chip and the second chip. In the flip-chip bonding method, the method further comprises a step of defoaming the sealing resin after being provided.

  According to a fifth aspect of the present invention, in the flip chip bonding method according to any one of the first to fourth aspects, either one of the first chip and the second chip is mounted on a mounting table of a bonding apparatus. In addition, the tip is held movably in the vertical direction within a range of a predetermined position, the other is held by a load applying head that presses the tip against the tip on the mounting table with a predetermined load, and the load adding head is held at a predetermined position. The first chip and the second chip are arranged opposite to each other so that the terminals are opposed to each other, and the first chip and the second chip are pressed with the predetermined load. In the flip-chip bonding method, the bonding metal is melted and cooled and solidified under heating conditions that do not satisfy the curing start condition of the resin for sealing material.

  According to a sixth aspect of the present invention, in the flip-chip bonding method according to the fifth aspect, the load applying head is provided on a moving head of a moving mechanism capable of positioning relative to the mounting table. And a tip holding portion provided at the tip of the load applying mechanism, and the load applying mechanism is configured such that when the tip held by the tip holding portion comes into contact with the tip supported downward, The flip chip bonding method is characterized in that it functions to press with a predetermined load within a range of positions.

  According to a seventh aspect of the present invention, in the flip chip bonding method according to the fifth or sixth aspect, the load holding mechanism supports the chip holding portion via an elastic member that is pressed by a predetermined elastic force. The flip-chip bonding method is characterized in that:

  According to an eighth aspect of the present invention, in the flip-chip bonding method according to the fifth or sixth aspect, the load holding mechanism moves in a vertical direction with respect to a fixed portion fixed to the movable head and the fixed portion. And a moving part provided with the chip holding part, and holding the moving part in a floating state by applying a buoyancy to the fixed part by a magnetic force. The moving part and the chip The flip chip bonding method is characterized in that a difference between the weight of the holding portion and the buoyancy is used as a downward pressing load.

  According to a ninth aspect of the present invention, in the flip-chip bonding method according to any one of the first to eighth aspects, the encapsulating resin is a thermosetting resin containing a polymerization initiator having a carboxyl group. The flip-chip bonding method is characterized by the above.

  According to a tenth aspect of the present invention, in the flip chip bonding method according to any one of the first to ninth aspects, the devoiding is performed in a reduced pressure atmosphere.

  According to an eleventh aspect of the present invention, in the flip chip bonding method according to any one of the first to tenth aspects, the first chip is a wiring board, and the second chip is a semiconductor chip on the first chip. In the flip-chip bonding method, the step of devoiding the sealing material after bonding a plurality of the steps, and the step of curing the resin for the sealing material are performed thereafter.

  According to a twelfth aspect of the present invention, there is provided a semiconductor device manufacturing method characterized by manufacturing a semiconductor device using the flip-chip bonding method according to any one of the first to eleventh aspects.

  According to a thirteenth aspect of the present invention, in the method for manufacturing a semiconductor device according to the twelfth aspect, a system-in-package module as a single semiconductor device is manufactured by arranging or stacking a plurality of semiconductor chips. A method of manufacturing a semiconductor device.

  According to a fourteenth aspect of the present invention, in the method for manufacturing a semiconductor device according to the thirteenth aspect, the system-in-package module is further wire-bonded or flip-chip mounted on a wiring board and sealed to be packaged. A method of manufacturing a semiconductor device.

  According to the present invention, there is little risk of occurrence of bonding failure in FC bonding by the first underfill method, and an FC bonding method capable of dealing with a narrow terminal interval, and manufacturing of a semiconductor device using these narrow terminal interval FC bonding methods A method can be provided.

  Embodiments of the present invention will be described below. In addition, this invention is not limited to embodiment shown below.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an outline of an example of a semiconductor device manufactured by the FC bonding method of the present invention.

  As shown in FIG. 1, in the semiconductor device 1, a terminal 11 of a first semiconductor chip 10 and a terminal 21 of a second semiconductor chip 20 are melt-bonded using a bonding metal 30 such as solder, and A space between the first and second semiconductor chips 10 and 20 is sealed with a sealing material 40 mainly composed of a thermosetting resin.

  The FC bonding method of the present invention can be applied to the manufacture of the semiconductor device 1 as shown in FIG. 1, and the FC bonding method according to this embodiment will be described below. Note that this embodiment is a joining apparatus called an FC bonder that can perform FC joining by applying a constant load from the start of heating of the joining metal to the end of solidification when joining with the joining metal. It is an example in the case of performing FC joining using the. Note that this FC bonder is different from the one that keeps the load constant by the drive control of the motor by the feedback of the load measurement.

  2A to 2G show the flow of the FC joining method in the present embodiment.

  As shown in FIG. 2 (a), the first semiconductor chip 10 is placed, and the terminal 11 is covered on the surface on which the terminal 11 is provided, as shown in FIG. 2 (b). An underfill material 41 which is a sealing material resin to be the material 40 is provided by application, printing, sticking, placement, or the like by dropping, spin coating, or the like.

  Next, in the present embodiment, as shown in FIG. 2 (c), the underfill material 41 is softened. However, the underfill material 41 is held in a reduced pressure (250 to 260 torr) state at a temperature lower than the gelation or curing temperature. Before defoaming 41, defoaming treatment is performed. Such a pre-defoaming process is performed in order to remove the bubbles 51 generated by wrapping or the like when the underfill material 41 is provided on the first semiconductor chip 10 in FIG.

  Next, as shown in FIG. 2 (d), the second semiconductor chip 20 in which the bonding metal 30 is provided on the terminal 21 is formed on the first semiconductor chip 10 in which the underfill material 41 is provided. The terminals 11 and 21 are positioned and arranged so as to be in close contact via the bonding metal 30.

  Next, as shown in FIG. 2E, the bonding metal 30 is brought to a temperature several tens of degrees higher than its melting point in a state where the terminals 11 and 21 are in close contact with each other and a predetermined load is applied between them. By heating and melting, the terminals 11 and 21 are connected to each other through the bonding metal 30 and then cooled, whereby the terminals 11 of the first semiconductor chip 10 and the terminals 21 of the second semiconductor chip 20 are cooled. And join. Here, a joining device called an FC bonder is used in the joining step using the joining metal 30 between the terminals 11 and 21. Details of the FC bonder will be described later.

  Subsequently, the underfill material 41 is devoided. This devoiding may be carried out while it is mounted on the FC bonder, but it is removed from the FC bonder and, for example, carried out with a reduced pressure heating device. That is, a temperature at which the semiconductor chip to which the terminals 11 and 21 are bonded is removed and transferred to a heating device capable of adjusting the indoor pressure to lower the viscosity of the underfill material 41, but is lower than the curing start temperature and Voiding is performed by leaving it under reduced pressure (250 to 260 torr). As a result, the void 52 made of water or the like generated when the air entrained during the FC bonding or the surface oxide film of the bonding metal 30 is removed by the action of the underfill material 41 as described later is removed.

  FIG. 2 (f) shows the state after the post-defoaming is completed. After the void removal is completed in this manner, the underfill material 41 is cured to form the sealing material 40. This state is shown in FIG. Such a curing process may be performed at a temperature lower than the melting point of the bonding metal 30 and under heating conditions in which the underfill material 41 is gelled or cured. Moreover, although this hardening process may be performed by a reduced pressure heating apparatus following devoid of voids, it may be separately performed by a diffusion furnace or the like.

  Further, the post-defoaming and the curing step may be performed simultaneously. That is, defoaming may be performed at a heating temperature at which gelation or curing of the underfill material 41 is started, and curing may be completed after the devoid of voids.

  In the FC joining method of the present embodiment described above, the underfill material 41 needs to satisfy a predetermined condition.

  That is, first, the underfill material 41 has a function of removing the oxide film on the surface of the bonding metal 30 and the terminals 11 and 21, particularly the surface of the bonding metal 30. As the underfill material 41 having such a function, for example, a material in which an epoxy resin as a thermosetting resin is a main component and a polymerization initiator having a carboxyl group is added can be exemplified.

  By using the sealing material resin having such an oxide film removing action, contact failure between the terminals 11 and 21 due to the oxide film on the surface of the bonding metal 30 can be prevented.

  Secondly, as the underfill material 41, a material that does not satisfy the curing start condition under the heating condition in the FC bonding is used. That is, as the underfill material 41, a material that does not start to cure is used depending on the heating conditions in the FC joining between the terminals 11 and 21 through the joining metal 30. Here, the underfill material 41 is a material in which the main component reacts with the polymerization initiator to start polymerization and gel or harden. Therefore, in the state where the polymerization initiator is already mixed, even at room temperature. In part or at very low rates, the gelling or curing reaction is initiated. Therefore, the curing start in the present invention means that the gelation or curing reaction starts as a whole by heating for a predetermined time at a predetermined heating temperature, and the condition for making such a reaction state is the curing start condition. .

  As such an underfill material 41, for example, even when heated to a temperature that is 140 ° C. or higher, which is a gelation start temperature of a general thermosetting resin, and exceeds the melting point of the bonding metal 30, a predetermined time or longer does not elapse. And those that do not satisfy the conditions for starting curing. That is, for example, a heating condition by a general FC bonder, for example, a heating condition at 260 ° C. of about 10 seconds to 30 seconds, specifically a thermal history from the start of heating, for example, a general thermosetting resin A material that does not start the curing reaction is used even if it is heated for a total of about 200 seconds until it is heated from 140 ° C. to 260 ° C., which is a heating temperature as a curing start condition, and cooled to less than 140 ° C.

  Therefore, as the underfill material 41, for example, any temperature of 140 ° C. to 200 ° C., preferably any temperature of 150 ° C. to 180 ° C. is a predetermined temperature that satisfies the curing start condition, and is equal to or higher than the predetermined temperature. Is used for a predetermined time, for example, at least 30 seconds or more, preferably 60 seconds or more, and more preferably 120 seconds or more and about 200 seconds.

  When such an underfill material 41 is used, in the FC joining in which the joining metal 30 is melted and cooled and solidified, the temperature equal to or higher than the predetermined temperature satisfying the curing start condition is 200 seconds or less, preferably 150 seconds or less. May be performed under heating conditions within 120 seconds, more preferably within 60 seconds, and further within 30 seconds.

  In addition, as long as the underfill material 41 has an oxide film removing action and has a curing start condition that satisfies a predetermined condition as described above, the thermosetting property includes a polymerization initiator having a carboxyl group. Needless to say, the resin is not limited.

  In the FC bonding method of this embodiment, as shown in FIGS. 2B to 2C, after providing the underfill material 41 on the surface of the first semiconductor chip 10, defoaming treatment is performed, and the underfill is performed. The air bubbles 51 entrained when the material 41 is provided are removed, but the defoaming process is not performed, and the defoaming process in FIGS. 2 (e) to 2 (f) described above is performed together. You may do it.

  The devoid treatment of FIGS. 2E to 2F is essential, and as a result, the water generated when the oxide film on the surface of the bonding metal 30 is removed by the action of the underfill material 41 as described above. Then, the void 52 made of entrained air is removed. Thereby, the short circuit and corrosion between terminals after sealing by the sealing material 40 can be prevented, and reliability can be improved.

  Such defoaming or devoiding treatment does not satisfy the curing start condition of the underfill material 41, but may be performed under heating conditions that reduce the viscosity of the underfill material 41. As described above, What is necessary is just to carry out at the heating temperature which does not reach the predetermined temperature used as hardening start conditions, and should just be made into the state which the viscosity of the underfill material 41 fell so that defoaming or devoid can be carried out. Specifically, it may be performed at 80 ° C. to 130 ° C., preferably 100 ° C. to 130 ° C., more preferably 110 ° C. to 120 ° C., and the viscosity of the underfill material 41 is, for example, 1.0 Pa · s. The following is preferable.

  In this embodiment, as the bonding metal 30, a material having a melting point higher than a predetermined temperature that is a condition for starting the curing of the underfill material 41 is used. Thereby, the remelting of the bonding metal 30 is prevented during the curing process of the underfill material 41 after the FC bonding, and the reliability of the FC bonding is maintained.

  In the present embodiment, a constant load is applied between the terminal 11 of the first semiconductor chip 10 and the terminal 21 of the second semiconductor chip 20 in the FC bonding process in which the bonding metal 30 is melted and cooled and solidified. An FC bonder that functioned to be added was used.

  Such an FC bonder has a mounting table on which the first semiconductor chip 10 is mounted, and the second semiconductor chip 20 is disposed opposite to the first semiconductor chip 10 so that it can move in the vertical direction within a range of a predetermined position. And a load applying head that presses the second semiconductor chip 20 against the first semiconductor chip 10 with a predetermined load.

  More specifically, the load application head includes a load application mechanism provided on the moving head of the movement mechanism that can be positioned and moved with respect to the mounting table, and a tip holding unit provided at the tip of the load application mechanism. The load applying mechanism functions so as to press with a predetermined load within a range of a predetermined position when the chip held by the chip holding portion comes into contact with the chip supported below.

  Here, functioning to press with a predetermined load within a range of a predetermined position does not mean that the actuator is feedback-controlled with a detected load to keep the load constant, but an elastic member that presses with a predetermined elastic force. A chip holding part that supports the chip holding part, or a chip holding part that holds the first semiconductor chip 10 is applied to the lower side only by a certain load. Specifically, the former is one in which the chip holding portion is supported by a coil spring having a small spring constant.

  In the latter, the load holding mechanism includes a fixed portion fixed to the moving head and a movable portion that is movable in the vertical direction with respect to the fixed portion and is provided with the chip holding portion, and is fixed by magnetic force. On the other hand, buoyancy is given to the moving part to hold it in a floating state, and the difference between the weight of the moving part and the chip holding part and the buoyancy is used as a downward pressing load.

  Here, an example of a specific FC bonder having the latter configuration will be described with reference to FIG. In addition, FIG. 3 is for demonstrating the structure which adds a fixed press load, and is abbreviate | omitting about the general structure as a bonder. In other words, as described above, the FC bonder includes a mechanism for precisely positioning and moving the terminals 11 and 12 in the plane direction (X and Y directions), and heating means for FC bonding is also provided. However, these are omitted in the following description, and only characteristic configurations will be described.

  As shown in FIG. 3, a column 102 is erected on a mounting table 101 on which the first semiconductor chip 10 is mounted, and a spindle head 103 is provided above the column 102. The spindle head 103 is provided with a drive means (not shown). A feed screw shaft 104 directed downward is rotatably supported by the drive means, and a feed nut 105 that engages with the feed screw shaft 104 and can be moved up and down. Is provided. A connecting member 106 is fixed to the feed nut 105, and the connecting member 106 meshes with a guide 107 provided on the side surface of the column 102 so as to be movable in the vertical direction. It is held up and down freely.

  With such a configuration, when the feed screw shaft 104 is rotated by driving the driving means provided in the spindle head 103, the feed nut 105 moves in the vertical direction, so that the feed screw shaft 104 and the feed nut 105 move. The mechanism is configured, and the feed nut 105 functions as a moving head.

  A load applying mechanism 108 constituting a load applying head is attached to the feed nut 105 which is a moving head. The load applying mechanism 108 includes a fixing portion 109 fixed to the feed nut 105 and a moving portion 110 to which a predetermined buoyancy is given to the fixing portion 109, and a tip holding portion is provided at the lower end portion of the moving portion 110. 111 is provided, and the second semiconductor chip 20 is held by the chip holding portion 111.

  The load applying mechanism 108 generates a magnetic force opposite to the fixed portion 109 and the moving portion 110 and controls the strength thereof, whereby a predetermined buoyancy is applied to the moving portion 110 by the interaction of the magnetic forces between the fixed portion 109 and the moving portion 110. Is to give. In the present embodiment, the permanent magnet is built in the fixed portion 109, while the moving portion 110 is provided with an electromagnet, and the magnitude of current to the electromagnet in the moving portion 110 is adjusted to adjust the magnitude of buoyancy. To be able to. It should be noted that the electromagnet and the permanent magnet may be provided in reverse, or both may be electromagnets, or both may be provided with permanent magnets, and either one may be provided with an electromagnet for adjusting buoyancy. Is not limited.

  Further, the moving unit 110 is not restricted from moving in the vertical direction with respect to the fixed unit 109, and is merely held so as not to fall by a stopper (not shown). Therefore, in a state where the second semiconductor chip 20 and the first semiconductor chip 10 are in contact with each other, the second semiconductor chip 20 is removed from the total weight of the moving unit 110, the chip holding unit 111, and the second semiconductor chip 20. The lower first semiconductor chip 10 is pressed with a load obtained by subtracting a predetermined buoyancy, and is movable up and down within a predetermined movement range (unless regulated by a stopper).

  When joining the terminals 11 and 21 shown in FIGS. 2D and 2E using the FC bonder of FIG. 3, the first semiconductor chip 10 is first mounted on the mounting table 101. After the second semiconductor chip 20 is held by the chip holding part 111, the alignment is performed so that the terminals 11 and 21 of the semiconductor chips 10 and 20 to be bonded to each other are opposed to each other.

  Next, the feed screw shaft 104 of the moving mechanism is driven to move below the feed nut 105, and the second semiconductor chip 20 held by the chip holding part 111 approaches the first semiconductor chip 10 on the mounting table 101. The distance between the first semiconductor chip 10 and the second semiconductor chip 20 is controlled to bring the terminals 11 and 21 of the two semiconductor chips into a substantially contact state.

  When bringing the first semiconductor chip 10 and the second semiconductor chip 20 into a substantially contact state, the underfill material 41 may be heated by a heating mechanism to reduce its viscosity.

  After that, the buoyancy is set to a predetermined value by using a load applying mechanism 108 that can apply a load independently of the moving mechanism, and the second semiconductor chip 20 includes the moving unit 110, the chip holding unit 111, and the second The lower first semiconductor chip 10 is pressed with a load obtained by subtracting a predetermined buoyancy from the total weight of the semiconductor chip 20. The load at this time may be a desired value in the range of, for example, 5 to 100 gf, and this value is not changed from the start to the end of the FC joining process.

  In this state, the joining metal 30 provided between the terminals 11 and 21 is melted by heating to a temperature several tens of degrees higher than the melting point of the joining metal 30 by a heating mechanism, and then cooled to join. The metal 30 is solidified, and the terminals 11 and 21 are FC joined.

  Here, FIG. 4 shows a conceptual description of the joining process of the present embodiment. As shown in FIG. 4, in the state A, after the terminals 11 and 21 are brought into a substantially contact state, the second semiconductor chip 20 is moved to the moving part 110 and the chip holding part by setting the buoyancy to a predetermined value using the load applying mechanism 108. 111 and the second semiconductor chip 20 are in contact with each other so as to press the lower first semiconductor chip 10 with a load obtained by subtracting a predetermined buoyancy from the total weight of the second semiconductor chip 20. In this state, the bonding metal 30 is in contact.

  When the temperature is increased from this state and the bonding metal 30 is melted, as shown in state B, the terminal 11 and the terminal 21 are somewhat closer, but the load pressing the terminal 11 is not changed at all. And if it cools in this state, joining of the terminals 11 and 12 will be completed, and it will be in the state C. FIG.

  As described above, when the FC bonder shown in FIG. 3 is used, the load between the terminals 11 and 12 is completely constant in the joining process, but an elastic member that presses with a predetermined elastic force can be used as the load adding mechanism 108. Good. In this case, an elastic member having a small spring constant separated from the driving means can be used. Therefore, when the elastic force is adjusted so that a predetermined load is applied in the state A, the elastic member is somewhat elastic due to the displacement from the state A to the state B. Although the force changes, the amount of change is minute and the applied load can be kept almost constant.

In the present embodiment, the first semiconductor chip 10 is a logic chip having a side of 10.5 mm and 50 μm square terminals 11 at a 100 μm pitch, and the second semiconductor chip 20 is a 50 μm square. A memory chip having terminals 21 at a pitch of 100 μm was used. The terminal 11 has a structure in which nickel and gold are provided on a copper layer. The terminal 11 has a structure in which a nickel layer having a thickness of about 25 μm is provided on the copper layer. The metal 30 was made of tin-silver solder (Sn ₃ Ag) having a melting point of 230 ° C. Then, after pre-defoaming treatment at 120 ° C. for 30 minutes, bonding treatment is performed by heating at 260 ° C. for 10 seconds under the condition of an additional load of about 50 g, and further under reduced pressure conditions of 250 torr, 120 ° Devoid treatment was performed by heat treatment at 30 ° C. for 30 minutes, and finally, curing treatment was performed at 175 ° C. for 30 minutes.

  As a result, the chip interval is 220 μm, and the protrusion of the sealing material 40 from the second semiconductor chip 21 in the side direction is as small as 200 to 350 μm, and wire bonding provided around the first semiconductor chip 10. No sealing material was applied to the pad for use.

  FIG. 5 shows an example of a state in which the first semiconductor chip 10 provided with the second semiconductor chip 20 is mounted on the third semiconductor chip 60 as described above. In this case, the wire bonding pad 12 provided around the first semiconductor chip 10 and the pad 61 of the third semiconductor chip 60 are bonded by wire bonding, and the first semiconductor chip 10 and the second semiconductor chip are connected. 20 is molded with a mold resin 70. In this case, since the protrusion of the sealing material 40 is small, the pads 12 can be provided close to each other, and the space can be saved as a whole.

(Second Embodiment)
The present embodiment is an example in which a semiconductor device is manufactured by FC bonding a plurality of semiconductor chips to one semiconductor chip in the FC bonding of the first embodiment.

  A method of manufacturing a semiconductor device according to the second embodiment of the present invention will be described with reference to FIG.

  First, an underfill material 41 is applied to the surface of the first semiconductor chip 10A on which the terminals 11A are provided by injection, printing, or spin coating using a resin injection device, and pre-defoaming as in the first embodiment. (See FIG. 6 (a)). This pre-defoaming may be omitted.

  Next, as shown in FIG. 6B, the terminal 21A of the second semiconductor chip 20A and the terminal 11A of the first semiconductor chip are the same as in the first embodiment (FIGS. 2D to 2E). ), The terminal 11 </ b> A and the terminal 21 </ b> A are joined via the joining metal 30. Thereafter, the second semiconductor chip 20B is bonded in the same manner without performing the void removal and underfill material curing completion steps. Thereafter, by performing a void removal and underfill material curing step in the same manner as in FIGS. 2F to 2G, the terminal 11A of the first semiconductor chip 10A and the terminal 21A of the second semiconductor chips 20A and 20B are obtained. , 21B are joined in the same manner as in the first embodiment (see FIGS. 6C and 6D).

  The underfill material 41 used in the present embodiment has a predetermined curing start condition, and the second semiconductor chips 20A and 20B can be FC-bonded under a condition that does not satisfy the curing start condition. it can.

(Other embodiments)
In the above-described embodiment, the underfill material is provided on the semiconductor chip placed below. However, the underfill material may be provided on the semiconductor chip mounted on the moving side of the FC bonder.

  In this case, the underfill material can be applied to the entire surface by printing or spin coating. Also in this case, the defoaming treatment can be performed. Further, after the defoaming treatment, the glass substrate or the like may be brought into close contact with the surface to perform the surface flattening treatment. Furthermore, an underfill material can also be provided by sticking what was shape | molded in the film form.

  In addition, after FC bonding as shown in the above-described embodiment, an example of performing wire bonding when mounting on a wiring board or another semiconductor chip has been shown (FIG. 5), but in a via hole provided in the semiconductor chip Further, FC joining may be performed through the connecting portion.

  A semiconductor device (package) in which a semiconductor chip and a semiconductor chip are FC-bonded using the FC bonding method of the present invention can be mounted on a wiring board by wire bonding or FC bonding.

1 is a schematic cross-sectional view of a semiconductor device manufactured using an FC bonding method according to a first embodiment of the present invention. It is a figure which shows the flow of the FC joining method which concerns on 1st Embodiment of this invention. It is the schematic of the FC bonder which concerns on 1st Embodiment of this invention. It is a graph which shows temperature control and load addition control with time progress at the time of FC joining using the FC bonder concerning a 1st embodiment of the present invention. It is a cross-sectional schematic diagram which shows the application example of the semiconductor device manufactured using the FC joining method which concerns on 1st Embodiment of this invention. It is a figure which shows the flow of the FC joining method which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor device 10, 10A, 20, 20A, 20B Semiconductor chip 11, 11A, 21, 21A, 21B Terminal 30 Joining metal 40 Sealing material 41 Underfill material

Claims (14)

A first chip and a second chip made of a semiconductor chip or a wiring substrate are arranged so that terminal surfaces provided with respective terminals face each other, and the first chip and the second chip are connected via a bonding metal provided on at least one terminal. In the flip chip bonding method for bonding the terminals of the second chip,
Providing a sealing material resin having an action of removing the oxide film on the surface of the bonding metal on either or both of the terminal surfaces provided with the terminals of the first chip and the second chip;
Next, after the first chip and the second chip are arranged to face each other so that the terminals face each other, the bonding metal is melted under heating conditions that do not satisfy the curing start condition of the encapsulant resin. A step of bonding the terminals together by applying a constant load between the terminals until the cooling and solidification after the bonding metal is melted after cooling and solidifying;
Next, a step of devoiding the encapsulant resin under a temperature condition that is lower than a predetermined temperature as the curing start condition and softens the encapsulant resin;
And a step of curing the resin for sealing material.   2. The flip-chip bonding method according to claim 1, wherein heating conditions from melting the bonding metal to cooling and solidification are equal to or higher than a predetermined temperature satisfying the curing start condition, but not satisfying the curing start condition. A flip chip bonding method characterized in that it is time.   3. The flip-chip bonding method according to claim 1, wherein the heating condition from melting of the bonding metal to cooling and solidification is heating at 140 ° C. or higher within 200 seconds. Flip chip bonding method. In the flip-chip bonding method according to any one of claims 1 to 3,
A flip chip bonding method comprising a step of defoaming the sealing material resin after providing the sealing material resin on one or both of the terminal surfaces of the first chip and the second chip .   5. The flip chip bonding method according to claim 1, wherein either one of the first chip and the second chip is mounted on a mounting table of a bonding apparatus, and the chip is within a range of a predetermined position. While holding the tip movably in the vertical direction, the other tip is held by a load applying head that presses the tip against the tip on the mounting table with a predetermined load, and the first tip is positioned in a predetermined position. And the second chip are arranged so that the terminals are opposed to each other, and the first chip and the second chip are pressed with the predetermined load, and the sealing material resin is cured in this state. A flip-chip bonding method, wherein the bonding metal is melted and cooled and solidified under a heating condition that does not satisfy a start condition.   6. The flip chip bonding method according to claim 5, wherein the load applying head is provided at a tip of the load adding mechanism provided on a moving head of a moving mechanism capable of positioning and moving with respect to the mounting table. And the load applying mechanism presses with a predetermined load within the range of the predetermined position when the chip held by the chip holding unit comes into contact with the chip supported below. Flip chip bonding method characterized by functioning as follows.   7. The flip chip bonding method according to claim 5, wherein the load holding mechanism supports the chip holding portion via an elastic member that is pressed by a predetermined elastic force. Method.   The flip chip bonding method according to claim 5 or 6, wherein the load holding mechanism is fixed to the movable head and is movable in the vertical direction with respect to the fixed portion, and the chip holding portion is provided. The moving part is provided with buoyancy to the moving part by magnetic force and held in a floating state, and the difference between the weight of the moving part and the chip holding part and the buoyancy is provided. The flip chip bonding method is characterized in that a downward pressing load is used.   9. The flip chip bonding method according to claim 1, wherein the sealing material resin is a thermosetting resin containing a polymerization initiator having a carboxyl group.   10. The flip chip bonding method according to claim 1, wherein the devoiding is performed in a reduced pressure atmosphere.   11. The flip chip bonding method according to claim 1, wherein the first chip is a wiring board, and a plurality of second chips that are semiconductor chips are bonded onto the first chip, and then the sealing material. And a step of curing the resin for sealing material, and a step of curing the resin for sealing material.   A semiconductor device manufacturing method using the flip chip bonding method according to claim 1.   13. The method of manufacturing a semiconductor device according to claim 12, wherein a system-in-package module that is one semiconductor device is manufactured by arranging or stacking a plurality of semiconductor chips.   14. The method of manufacturing a semiconductor device according to claim 13, wherein the system-in-package module is further wire-bonded or flip-chip mounted on a wiring board, and sealed and packaged.

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