JP5210496B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a method of manufacturing a semiconductor device in which a substrate having protruding electrodes is mounted by FC (flip chip).

  In recent years, COC (Chip On Chip) mounting in which semiconductor chips are stacked and connected has been attracting attention as mobile phones and personal computers become smaller and lighter and have higher functions. In this mounting, flip chip connection is indispensable due to the necessity of high-speed transmission characteristics. Flip chip connection is a method in which lead wires are not drawn from a semiconductor chip to a substrate (printed circuit board, interposer, etc.), and the semiconductor chip is connected to the substrate through bump electrodes called two-dimensionally arranged bumps. The COC mounting is realized by connecting the protruding electrodes on the surfaces of each other or by connecting the protruding electrodes on one surface and the extraction electrodes on the other surface.

  By the way, at present, flux is mainly used when the protruding electrode is bonded onto the extraction electrode. Flux is used for the purpose of reducing and removing oxides on the surface and inside of the protruding electrode and preventing oxidation of the protruding electrode surface. If the protruding electrode remains on the substrate after joining the extraction electrode, Affects the reliability of the product. Therefore, it is necessary to clean and remove the flux residue remaining in the gap so that the flux does not remain in the gap between the semiconductor chip and the substrate.

  However, the gap between the semiconductor chip and the substrate in flip chip connection is predicted to be 50 μm or less in the future, and it becomes extremely difficult to clean and remove the flux residue remaining in the gap. Moreover, it is not easy to completely remove the flux residue. Therefore, in recent years, a technique for joining the protruding electrode on the extraction electrode without using a flux has been actively proposed. For example, in Patent Document 1, after temporarily fixing the protruding electrode on the extraction electrode using an adhesive mainly composed of alcohol or organic acid, the protruding electrode is exposed to an atmosphere containing free radical gas (hydrogen radical). In addition, a technique is disclosed in which the oxide film on the surface of the protruding electrode is chemically treated (removed) and heat treatment is performed to bond the protruding electrode onto the extraction electrode.

JP 2005-230830 A

  However, it is not easy to align the semiconductor chip and the substrate in a vacuum atmosphere after bonding the protruding electrode onto the extraction electrode as in Patent Document 1. Therefore, the alignment is usually performed after the semiconductor chip and the substrate are taken out into the atmosphere. However, when the semiconductor chip and the substrate are exposed to the atmosphere for a long time, an oxide film is formed again on the surface of the protruding electrode, which may deteriorate the electrical contact between the electrodes.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a method of manufacturing a semiconductor device that can be easily flip-chip connected without deteriorating the electrical contact between electrodes. There is.

The method for manufacturing a semiconductor device of the present invention includes the following steps (A) to (D).
(A) A step of preparing a first substrate and a second substrate having electrodes on the surface and having protruding electrodes on at least one electrode surface (B) of each electrode and protruding electrode of the first substrate and the second substrate A step of removing the first substrate and the second substrate into the atmosphere after chemically treating the surface with a free radical gas, a reducing gas, or an organic acid vaporized gas (C) The first substrate and the second substrate in the atmosphere (2) A step of placing the first substrate and the second substrate in a low oxygen concentration atmosphere while aligning the electrodes or the protruding electrodes of the two substrates, and (D) projecting the first substrate and the second substrate in the low oxygen concentration atmosphere. Step of performing heat treatment under temperature condition where electrode is melted Here, in the positioning step (step C), the first substrate and the second substrate have a temperature x (° C.) and an exposure period y (seconds) that satisfy the following expression: ) It is only exposed to the atmosphere.
y ≦ 10 ^{− (x−57.45) /6.031} (excluding the exposure period y within 5 hours)
Here, the protruding electrode is made of tin containing silver and copper, or made of tin containing at least lead out of lead and phosphorus. When the protruding electrode is made of tin containing silver and copper, the surface of the electrode contains copper, gold, silver or palladium. When the protruding electrode is made of tin containing at least lead among lead and phosphorus, the surface of the electrode contains gold, silver, or palladium.

In the method for manufacturing a semiconductor device of the present invention, the oxide film on the surface of each electrode or protruding electrode of the first substrate and the second substrate is removed by chemical treatment with a free radical gas, a reducing gas, or an organic acid vaporized gas. After that, the first substrate and the second substrate are taken out from the apparatus that has performed the chemical treatment into the atmosphere, and the alignment of the electrodes or the protruding electrodes of the first substrate and the second substrate is performed in another apparatus. . At this time, each electrode or protruding electrode of the first substrate and the second substrate is within a range of temperature x (° C.) and exposure period y (second) satisfying the above-described formula (excluding the exposure period within 5 hours) . It is made to be exposed to the atmosphere only inside.

  According to the method for manufacturing a semiconductor device of the present invention, after the first substrate and the second substrate are taken out into the atmosphere, the respective electrodes or protruding electrodes of the first substrate and the second substrate are aligned. The first substrate and the second substrate can be easily aligned as compared with the case of performing in a low-pressure atmosphere. In addition, the electrodes or protruding electrodes of the first substrate and the second substrate are exposed to the atmosphere only within the range of the temperature x (° C.) and the exposure period y (seconds) satisfying the expressions (1) and (2). Therefore, the thickness of the oxide film formed on the surface of the electrode or the protruding electrode during exposure to the atmosphere can be prevented from becoming thicker than a predetermined value. Further, since the subsequent heat treatment process is performed in a low oxygen concentration atmosphere, the protruding electrodes can be sufficiently wetted, and the respective electrodes or protruding electrodes of the first substrate and the second substrate can be reliably bonded. it can. Therefore, the flip chip connection can be easily performed without deteriorating the electrical contact between the electrodes.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a semiconductor device 1 according to an embodiment of the present invention, and FIG. 2 shows a flow of a manufacturing method of the semiconductor device 1 of FIG. This semiconductor device 1 is obtained by bonding a semiconductor chip 2 (first substrate) to an intermediate substrate 3 (second substrate).

  The semiconductor chip 2 has a semiconductor element 4, an external extraction electrode 5, and a protruding electrode 6. The semiconductor element 4 has an integrated circuit (not shown) incorporated therein, for example. The external extraction electrode 5 is formed on the surface of the semiconductor element 4 and is connected to, for example, one end of the integrated circuit. The protruding electrode 6 is formed on the surface of the external extraction electrode 5.

  The intermediate substrate 3 electrically connects, for example, the external extraction electrode 5 of the semiconductor chip 2 and an electrode pad (not shown) provided on the surface of a printed board (not shown) for mounting the semiconductor device 1. An interposer for connection, having an insulating substrate 7, a via (not shown) penetrating through the insulating substrate 7, and an external extraction electrode 8 connected to the via and formed on the surface of the intermediate substrate 3 ing.

  Here, at least the surfaces of the external extraction electrodes 5 and 8 are made of, for example, a metal containing Cu (copper), Au (gold), Pd (palladium), Ag (silver), In (indium), or Sn (tin). Has been. The protruding electrode 6 may be, for example, Sn (tin) containing no impurities, Ag (silver), Cu (copper), Bi (bismuth), In (indium), Ni (nickel), Au (gold), P ( It is made of tin containing at least one impurity of phosphorus and Pb (lead), and is formed by, for example, plating, printing, ball, or vapor deposition.

  Below, with reference to FIGS. 2-7, the manufacturing method of the semiconductor device 1 of embodiment of this invention is demonstrated.

  First, the oxide film removing apparatus 10 and the heat treatment apparatus 50 used when implementing the method for manufacturing the semiconductor device 1 will be described.

  The oxide film removing apparatus 10 is an apparatus for removing an oxide film covering the surfaces of the external extraction electrodes 5 and 8 and the protruding electrodes 6. As shown in FIG. 3, the oxide film removing apparatus 10 includes a chamber 11 including an upper chamber 11A and a lower chamber 11B that are spatially separated from each other. In the upper chamber 11A, a microwave generator 14 that generates a microwave W is disposed via a waveguide 13 and a microwave introduction window 12, and a hydrogen gas source 16 that generates hydrogen gas is a supply pipe. 15 is arranged. As a result, the upper chamber 11 </ b> A converts the hydrogen gas supplied from the hydrogen gas source 16 into plasma by the microwave W generated by the microwave generator 14 to generate hydrogen radicals (free radical gas).

  The upper chamber 11A is also provided with a shield 17 on the bottom side of the plasma generation region P and a nozzle 18 on the bottom surface. The shield 17 is made of, for example, a wire mesh, collects unnecessary charged particles present in the plasma as much as possible, and introduces gas contained in the plasma generated in the upper chamber 11A into the lower chamber 11B. ing. As a result, the upper chamber 11A introduces a gas containing hydrogen radicals into the lower chamber 11B through the shield 17.

  The lower chamber 11B is provided with a support base 18 on which a processing object (semiconductor chip 2 and intermediate substrate 3) is placed. The support base 18 includes a heater 19 and a cooler 20 in a portion that supports the semiconductor chip 2 and the intermediate substrate 3, and can heat and cool the semiconductor chip 2 and the intermediate substrate 3 in a predetermined procedure. It has become. The lower chamber 11B is also provided with a vacuum pump 22 at the bottom via an exhaust port 21 and a pressure gauge 23 at the bottom. The vacuum pump 22 is for exhausting the gas in the chamber 11 to reduce the pressure in the chamber 11. The pressure gauge 23 is for measuring the pressure in the chamber 11. The lower chamber 11B is further provided with a nitrogen gas source 25 through a supply pipe 24. The nitrogen gas source 25 may be provided on the upper chamber 11A side. The measurement value of the pressure gauge 23 is transmitted to the control unit 26, and the control unit 26 controls the hydrogen gas source 15, the vacuum pump 22, and the nitrogen gas source 25 based on the measurement value. Thereby, a process target object can be exposed to the gas containing a hydrogen radical.

  The heat treatment apparatus 50 is an apparatus for melting the protruding electrode 6 and electrically bonding the protruding electrode 6 of the semiconductor chip 2 and the external extraction electrode 8 of the intermediate substrate 3 to each other (flip chip connection). The heat treatment apparatus 50 is, for example, a continuous reflow apparatus capable of continuously supplying a processing object into the chamber as shown in FIG. This reflow apparatus has a chamber 51 provided with a sample inlet 52 on one side and a sample outlet 53 on a side opposite to the side. A belt conveyor 54 extending from the sample inlet 52 to the sample outlet 53 is provided in the chamber 51 so that the sample is transported from the sample inlet 52 side to the sample outlet 53 side. Within the chamber 51, a heater 55 is provided on the upstream side of the belt conveyor 54, and a cooler 56 is provided on the downstream side. Nitrogen gas sources 58 are arranged on the upper and lower surfaces of the chamber 51 via supply pipes 57, respectively. The nitrogen gas source 58 supplies nitrogen gas into the chamber 51 so that the pressure inside the chamber 51 is higher than the pressure outside the chamber 51. Thereby, inflow of oxygen from the outside of the chamber 51 can be prevented, so that the inside of the chamber 51 can be in a low oxygen concentration atmosphere.

  The heat treatment apparatus 50 may be, for example, a batch-type reflow apparatus that places an object to be processed at a predetermined location in the chamber during the heat treatment, as shown in FIG. This reflow apparatus has a sealed chamber 61. In the chamber 61, a support table 62 for placing the processing object (semiconductor device 1) is provided. The support base 62 includes a heater 63 and a cooler 64 at a portion that supports the semiconductor device 1, and the semiconductor device 1 can be heated and cooled by a predetermined procedure. The chamber 61 is also provided with a vacuum pump 66 on the bottom via an exhaust port 65 and a pressure gauge 67 on the bottom. The vacuum pump 66 is for evacuating the gas in the chamber 61 to reduce the pressure in the chamber 61. The pressure gauge 67 is for measuring the pressure in the chamber 61. The chamber 61 is further provided with a nitrogen gas source 69 via a supply pipe 68. The measurement value of the pressure gauge 67 is transmitted to the control unit 70, and the control unit 70 controls the vacuum pump 66 and the nitrogen gas source 69 based on the measurement value. Thereby, the inside of the chamber 61 can be made into a low oxygen concentration atmosphere.

(Removal of oxide film)
The oxide film covering the surfaces of the external extraction electrodes 5 and 8 and the protruding electrode 6 is removed using the oxide film removing apparatus 10 having the above-described configuration.

  Specifically, first, the chamber 11 is opened, and the semiconductor chip 2 and the intermediate substrate 3 are placed on the support base 18 with the external extraction electrodes 5 and 8 and the protruding electrodes 6 facing up (step S1). FIG. 3 illustrates the case where the semiconductor chip 2 is placed on the support base 18. Subsequently, after the chamber 11 is closed, the vacuum pump 22 is operated to exhaust the gas in the chamber 11 and reduce the pressure (step S2).

  Next, the microwave generator 14 is operated to generate the microwave W, and the hydrogen gas source 16 is operated to generate hydrogen gas. As a result, the hydrogen gas is turned into plasma by the microwave W, and hydrogen radicals (free radical gas) are generated (step S3). As a result, hydrogen radicals generated in the upper chamber 11 </ b> A ride on the gas flow and pass through the shield 17 and are introduced into the lower chamber 11 </ b> B through the nozzle 18.

  The semiconductor chip 2 placed on the support base 18 and the external extraction electrodes 5, 8 and the protruding electrode 6 of the intermediate substrate 3 are exposed to a gas containing hydrogen radicals supplied from the nozzle 18. As a result, the oxide films covering the surfaces of the external extraction electrodes 5 and 8 and the protruding electrode 6 are chemically reacted with hydrogen radicals to be vaporized and removed from the surface (step S4).

(Alignment)
Next, after the semiconductor chip 2 and the intermediate substrate 3 are taken out into the atmosphere of a predetermined environment (step S5), the protruding electrode 6 of the semiconductor chip 2, the external extraction electrode 8 of the intermediate substrate 3 and the like within a predetermined period. Are aligned (see step S6, FIG. 6 and FIG. 7). Thereby, the alignment of the semiconductor chip 2 and the intermediate substrate 3 can be easily performed as compared with the case of performing in a low-pressure atmosphere. The explanation of the atmospheric environment and the period of exposure to the atmosphere will be described in detail later.

  When aligning, it is preferable that the protruding electrode 6 of the semiconductor chip 2 and the external extraction electrode 8 of the intermediate substrate 3 are temporarily fixed to each other. For example, an organic material or a fixing jig that does not easily generate a residue when reflow described later is performed, or the protruding electrode 6 of the semiconductor chip 2 is bonded to the external extraction electrode 8 of the intermediate substrate 3 by temporary bonding or ultrasonic waves. It is also possible to fix. Further, after the alignment, an inert gas or the like may be introduced into the gap between the semiconductor chip 2 and the intermediate substrate 3 and oxygen existing in the gap may be replaced with an inert gas or the like.

(Joining)
Next, the aligned semiconductor chip 2 and intermediate substrate 3 are put in the heat treatment apparatus 50, and reflow is performed in a low oxygen concentration atmosphere (step S7). Specifically, first, the inside of the heat treatment apparatus 50 is filled with nitrogen gas, and the nitrogen gas sources 58 and 69 are adjusted so that the oxygen concentration in the heat treatment apparatus 50 is 100 ppm or less, preferably 30 ppm or less. Next, the aligned semiconductor chip 2 and the intermediate substrate 3 are put into the heat treatment apparatus 50, and the semiconductor chip 2 and the intermediate substrate 3 are heated for a predetermined time under a temperature condition where the protruding electrode 6 is melted. The semiconductor chip 2 and the intermediate substrate 3 are cooled for a predetermined time under a temperature condition that allows the heated semiconductor chip 2 and the intermediate substrate 3 to be sufficiently cooled. Thereby, the protruding electrode 6 of the semiconductor chip 2 and the external extraction electrode 8 of the intermediate substrate 3 are joined to each other, and the semiconductor chip 2 and the intermediate substrate 3 are flip-chip connected. Thereafter, the semiconductor device 1 obtained by the flip chip connection is taken out from the heat treatment apparatus 50. In this way, the semiconductor device 1 of the present embodiment is manufactured by flip-chip connecting the semiconductor chip 2 and the intermediate substrate 3.

  By the way, in the above alignment step, an oxide film (for example, SnO) is formed on the surfaces of the external extraction electrodes 5 and 8 and the protruding electrode 6 while being exposed to the atmosphere. The thickness of the oxide film varies depending on the atmospheric temperature, humidity, exposure time in the atmosphere, and the like. However, if the thickness exceeds a certain value, the protruding electrode 6 may be sufficiently wetted in the subsequent heat treatment step. Thus, the protruding electrode 6 of the conductor chip 2 and the external extraction electrode 8 of the intermediate substrate 3 cannot be reliably bonded to each other. As a result, the reliability of the semiconductor device 1 may be reduced. Therefore, the thickness of the oxide film needs to be a thickness that can sufficiently wet the protruding electrode 6.

  At this time, it is important to objectively determine whether or not the protruding electrode 6 can be sufficiently wetted. One of the determination factors is a “wetting spread rate”. In the present embodiment, this wetting spread rate Z is defined as being obtained by 100 × (300 μm−H) / 300 μm.

  Here, 300 μm is the height of the ball made of the same material as the bump electrode 6. H is a ball having a diameter of 300 μm made of the same material as that of the protruding electrode 6 placed on a substrate made of the same material as that of the external extraction electrodes 5 and 8 and placed in a low oxygen concentration atmosphere having an oxygen concentration of 100 ppm. The height of the ball when reflow is performed at a temperature of 230 ° C. for 60 seconds. Note that 100 on the right side is for converting Z to%.

  When the wet spreading rate Z is 50% or more, the protruding electrode 6 can be sufficiently wetted. Conversely, when the wet spreading rate Z is less than 50%, the protruding electrode 6 can be sufficiently wetted. This means that the reliability and yield of the semiconductor device 1 may be reduced.

  Table 1 lists a plurality of combinations (materials A1 to A33) of materials (Sn, Ag, Cu, Bi, In, Ni, Au, P, and Pb) that can be considered as the material of the protruding electrode 6. Here, the value in Table 1 is the content rate (%). In addition, “remaining” in the Sn column means a value obtained by subtracting the ratio of the contained elements from 100, where 100 is the whole. Since the materials B1 and B2 contain Zn (zinc), the oxide film contains a large proportion of ZnO or NiO, and it is difficult to chemically remove the oxide film compared to SnO. Since it is an inappropriate material as the material of the bump electrode 6 of this embodiment, it is listed as a comparative example.

  Table 2 shows that the materials A1 to A35, B1, and B2 described above are considered as materials of the external extraction electrodes 5 and 8 (Cu (material C1), Au (material C2), Pd (material C3), Ag (material). C4), In (material C5), and Sn (material C6)). Here, the double circle in Table 2 means that the wetting spread rate Z is 70% or more, the single circle means that the wetting spread rate Z is 50% or more and less than 70%, and the cross means that the wetting spread rate Z is 50%. Means less. Since the materials D1 and D2 are Ni and Zn, the ratio of ZnO or NiO contained in the oxide film is large and the wettability is poor as compared with SnO, as in the above comparative example. Since the material of the external extraction electrodes 5 and 8 of this embodiment is an inappropriate material, it is listed as a comparative example.

  From Table 2, when the protruding electrode 6 is made of the materials A10 to A13 and A15 made of Sn and Pb or the material A14 made of Sn, Pb and P, the external lead electrodes 5 and 8 are made of the materials C1 to C6. In any case, the wetting spread rate Z is 70% or more. When the protruding electrode 6 is composed of other materials A1 to A9 and A16 to A33, the wet spreading rate Z is 70% or more when the external extraction electrodes 5 and 8 are composed of the material C2. . This is because the material C2 is Au which does not form an oxide film on the surface, and the chemical affinity between the material C2 and Sn is good. However, even when the external extraction electrodes 5 and 8 are made of materials C1, C3 to C5 other than the material C2, the wet spreading rate Z is 50% or more and less than 70%.

  As described above, there are a wide variety of combinations of the material of the protruding electrode 6 and the material of the external extraction electrodes 5 and 8 that have a wetting and spreading rate Z of 50% or more, but the protruding electrode 6 has a Zn or Ni content. In the case of being composed of many materials B1 and B2, the wet spreading rate Z is less than 50% even when the external extraction electrodes 5 and 8 are composed of any of the materials C1 to C6. End up. Further, in the case where the external extraction electrodes 5 and 8 are made of materials D1 and D2 made of Zn or Ni, even when the protruding electrode 6 is made of any of the materials A1 to A34, wetting is performed. The spreading rate Z is less than 50%.

  From these facts, it is not preferable to use a material containing Zn or Ni as the material of the protruding electrode 6 and the external extraction electrodes 5 and 8, and it is inappropriate to use a material containing a large amount of these. .

FIG. 8 shows the time change of the wetting spread rate Z on the material C1 when the ball material is the material A7. The solid line in FIG. 8 is a temperature 25 ° C., one-dot chain line temperature 36 ° C., a two-dot chain line are those at the temperature 45 ° C., a in FIG. 8 humidity 87g / cm ^-3, b, e humidity 10g / Cm ⁻³ (20%), c and f are at a humidity of 25 g / cm ⁻³ (60%), and d and g are at a humidity of 40 g / cm ⁻³ (95%).

From FIG. 8, it can be seen that, as an overall trend, the wet spreading rate Z is hardly affected by humidity, but is greatly affected as the temperature increases. Further, in order to set the wetting spread rate Z to 50% or more, it is necessary to make the exposure time within 2.4 × 10 ⁵ seconds (about 66 hours) when the temperature is 25 ° C., and the temperature is 36 ° C. In this case, the exposure time needs to be within 3.6 × 10 ³ seconds (about 1 hour), and when the temperature is 45 ° C., the exposure time is 1.6 × 10 ² seconds (about 2.5 It can be seen that it is necessary to be within minutes). This tendency is substantially the same even when other materials are used.

  FIG. 9 shows the relationship between the temperature x (° C.) and the exposure time y (seconds) when the wetting spread rate Z on the material C1 is 50% when the ball material is the material A7. It represents a relationship.

From FIG. 9, when the temperature x is 36 ° C. or lower, it is necessary to perform the alignment step at the temperature x satisfying the equation (1) and the exposure time y, and when the temperature x is higher than 36 ° C., the temperature satisfying the equation (2). It can be seen that it is necessary to perform the alignment process at x and exposure time y. This tendency is substantially the same even when other materials are used.
y ≦ 10 ^{− (x−57.45)} / ^6.031 (1)
y ≦ 10 ^{− (x-59.67) /6.656} (2)

  As described above, in the present embodiment, in the alignment step, the external extraction electrodes 5 and 8 and the protruding electrodes 6 of the semiconductor chip 2 and the intermediate substrate 3 satisfy the above formulas (1) and (2), respectively. Since the exposure to the atmosphere is performed only within the range of the temperature x and the exposure period y, the thicknesses of the oxide films formed on the surfaces of the external extraction electrodes 5 and 8 and the protruding electrodes 6 during the exposure to the atmosphere are reduced. It can prevent becoming thicker than a predetermined value. As a result, in the subsequent heat treatment step, the protruding electrode 6 can be sufficiently wetted, and the protruding electrode 6 of the semiconductor chip 2 and the external extraction electrode 8 of the intermediate substrate 3 can be reliably bonded.

  Further, as described above, the alignment of the semiconductor chip 2 and the intermediate substrate 3 can be easily performed as compared with the case where the alignment process is performed in a low-pressure atmosphere.

  Therefore, in the manufacturing method of the semiconductor device 1 of the present embodiment, the flip chip connection can be easily performed without deteriorating the electrical contact property between the protruding electrode 6 and the external extraction electrode 8.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, and various modifications can be made.

  For example, in the above embodiment, the protruding electrode 6 and the external extraction electrode 8 are bonded, but the protruding electrodes may be bonded to each other. In the above embodiment, the semiconductor chip 2 and the intermediate substrate 3 are bonded. However, the semiconductor chip 2 and the printed circuit board may be bonded to each other.

  Further, in the above embodiment, hydrogen radicals are used to remove the oxide films on the surfaces of the external extraction electrodes 5 and 8 and the protruding electrodes 6, but for example, hydrogen gas, a mixed gas of hydrogen gas and argon gas, or A reducing gas such as a mixed gas of hydrogen gas and nitrogen gas, or an organic acid vaporized gas such as formic acid may be used.

  Moreover, in the said embodiment, the atmosphere in the heat processing apparatus 50 at the time of performing reflow was the low oxygen concentration atmosphere containing nitrogen gas, However, Inert gas, free radical gas, reducing gas, or organic acid vaporization gas For example, a reducing atmosphere obtained by mixing 5% or less of hydrogen gas in a nitrogen atmosphere, or an inert gas atmosphere such as argon or helium may be used. Moreover, a vacuum may be sufficient.

  Further, at the time of alignment, the surface oxide films of the external extraction electrodes 5 and 8 and the protruding electrode 6 may be reduced or removed with ultrasonic waves or the like.

  In the above embodiment, the case where one semiconductor chip 2 and the intermediate substrate 3 are flip-chip connected has been described. However, the present invention is not limited to this, for example, as shown in FIG. In addition, the present invention is also applicable to a semiconductor device in which a semiconductor chip 9 having an external extraction electrode 5 on the upper surface of the semiconductor element 4 is provided between the semiconductor chip 2 and the intermediate substrate 3. The semiconductor element including the semiconductor chip 2 and one or a plurality of semiconductor chips 9 corresponds to an example of the “first substrate” in the present invention. Further, the present invention can be similarly applied to, for example, a semiconductor device in which a plurality of semiconductor chips 2 are provided on an intermediate substrate 3 as shown in FIG. The plurality of semiconductor chips 2 correspond to an example of the “first substrate” in the present invention.

  In the above embodiment, the removal of the oxide film and the flip chip connection are performed by different apparatuses. However, the present invention is not limited to this, and it is performed by the same apparatus. May be.

It is a section lineblock diagram of a semiconductor device concerning one embodiment of the present invention. 3 is a flowchart for explaining a manufacturing process of a semiconductor device according to an embodiment of the present invention; It is sectional drawing of the apparatus used at an oxide film removal process. It is sectional drawing of the continuous type apparatus used at a reflow process. It is sectional drawing of the batch type apparatus used at a reflow process. It is sectional drawing of the semiconductor chip and intermediate | middle board | substrate in an alignment process. FIG. 7 is a cross-sectional view for explaining a process following the process in FIG. 6. It is a related figure of a wetting spread rate and exposure time. FIG. 6 is a relationship diagram between a wetting spread rate and temperature. It is a section lineblock diagram of a semiconductor device concerning one modification of the present invention. It is a cross-sectional block diagram of the semiconductor device which concerns on the other modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2, 9 ... Semiconductor chip, 3 ... Intermediate substrate, 4 ... Semiconductor element, 5, 8 ... External extraction electrode, 6 ... Projection electrode, 7 ... Insulating substrate, 10 ... Oxide film removal apparatus, 11, 51 61 ... Chamber, 11A ... Upper chamber, 11B ... Lower chamber, 12 ... Microwave introduction window, 13 ... Waveguide, 14 ... Microwave generator, 15, 24, 57, 68 ... Supply pipe, 16 ... Hydrogen gas Source, 17 ... Shield, 18,62 ... Support, 19,55,63 ... Heater, 20,56,64 ... Cooler, 21,65 ... Exhaust port, 22,66 ... Vacuum pump, 23,67 ... Pressure Total, 25, 58, 69 ... Nitrogen gas source, 26, 70 ... Control unit, 50 ... Heat treatment device, 52 ... Sample inlet, 53 ... Sample outlet, 54 ... Belt conveyor.

Claims (8)

A free radical gas, a reducing gas, or an organic acid vaporized gas on the surface of each of the electrodes of the first substrate and the second substrate or the protruding electrode having the electrode on the surface and the protruding electrode on at least one electrode surface A step of taking out the first substrate and the second substrate into the atmosphere after performing a chemical treatment in
Aligning the respective electrodes and protruding electrodes of the first substrate and the second substrate in the atmosphere, and placing the first substrate and the second substrate in a low oxygen concentration atmosphere;
Heat-treating the first substrate and the second substrate in the low oxygen concentration atmosphere under a temperature condition for melting the protruding electrodes,
In the alignment step, the first substrate and the second substrate are exposed to the atmosphere only within a range of a temperature x (° C.) and an exposure period y (seconds) that satisfy the following formula :
The protruding electrode is made of tin containing silver and copper, or made of tin containing at least lead among lead and phosphorus,
When the protruding electrode is made of tin containing silver and copper, the surface of the electrode contains copper, gold, silver or palladium,
When the protruding electrode is made of tin containing at least lead among lead and phosphorus, the surface of the electrode contains gold, silver, or palladium.
y ≦ 10 ^{− (x−57.45) /6.031} (excluding the exposure period y within 5 hours) The low oxygen concentration atmosphere is a mixed gas of an inert gas and a free radical gas, a reducing gas or an organic acid vaporized gas, or a vacuum,
The method for manufacturing a semiconductor device according to claim 1, wherein the oxygen concentration contained in the low oxygen concentration atmosphere is 100 ppm or less. The method for manufacturing a semiconductor device according to claim 1, wherein the free radical gas includes hydrogen radicals. The method of manufacturing a semiconductor device according to claim 1, wherein the reducing gas includes hydrogen gas, a mixed gas of hydrogen gas and argon gas, or a mixed gas of hydrogen gas and nitrogen gas. The method of manufacturing a semiconductor device according to claim 1, wherein the organic acid vaporization gas includes formic acid. The method for manufacturing a semiconductor device according to claim 2, wherein the inert gas includes argon, nitrogen, or helium. The method of manufacturing a semiconductor device according to claim 1, wherein the protruding electrode is formed by plating, printing, ball, or vapor deposition. 2. The method of manufacturing a semiconductor device according to claim 1, wherein one of the first substrate and the second substrate is one or a plurality of semiconductor chips, and the other is an intermediate substrate or a printed circuit board.

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