JP5103690B2 - Method for inspecting bonding state of solder ball to semiconductor product substrate and inspection system thereof - Google Patents

Description

  The present invention relates to a method for inspecting a bonding state of a solder ball to a semiconductor product substrate and an inspection system therefor, and more particularly to a non-contact bonding state of a solder ball to a substrate of an integrated circuit package such as a BGA type package or a CSP type package. The present invention relates to a method for inspecting a bonding state of a solder ball to be inspected to a semiconductor product substrate and an inspection system therefor.

  The bonding state between the substrate electrode portion of the solder ball mounted semiconductor product such as the BGA type package or the CSP type package and the solder ball is a major factor affecting the life of the electronic device on which the semiconductor product is mounted. As a method for testing the bonding state of the solder ball to the substrate electrode part of the integrated circuit package described above, conventionally, the solder ball mounted semiconductor product is heated from the opposite side of the solder ball mounting surface, and the temperature change on each solder ball during heating is used. Inspection method to perform pass / fail judgment (Patent Document 1), after heating the entire solder ball mounted semiconductor product to a certain temperature, cool the opposite side of the solder ball mounted surface, and judge pass / fail by temperature change on the solder ball during cooling Non-destructive inspection methods, such as the method of doing this (Patent Document 2), are known. According to these methods, it is possible to reduce or reduce the time and cost of a destructive test involving pulling or shear fracture. On the other hand, in the method of Patent Document 1 of these Patent Documents, since the heating is performed from the opposite side of the solder ball mounting surface, the arrival time to the solder ball surface temperature necessary for pass / fail judgment is determined by the thickness of the solder ball mounted semiconductor product, This depends on the material and shape, and there are problems that the accuracy of the quality determination is lowered and the inspection time is extended. Further, in the method of Patent Document 2, it is necessary to always operate a cooling device for cooling, and since a coolant such as cold water or liquid nitrogen is used, it is necessary to take measures to prevent condensation of the cooling device depending on the use environment. There has been a problem of increasing the cost required for this. On the other hand, the applicant eliminates these defects by heating and cooling the solder ball mounting surface of the product and making a pass / fail judgment on the basis of the infrared data by the infrared detection means at that time. A method that can inspect the bonding state of a ball to a semiconductor product substrate with high efficiency and good accuracy at low cost has been proposed (Patent Document 3). By the way, when detecting the infrared rays from the solder ball mounting surface of the product and inspecting the quality of their joined state, the judgment result with higher accuracy is obtained when judging them as data by improving the emissivity of infrared rays. I can expect. In general, when the quality of solder balls in a semiconductor product mounted with solder balls is determined based on data based on the detection of emitted infrared rays, it is not possible to measure the exact temperature by directly measuring the subject, resulting in a decrease in inspection accuracy. There's a problem. Thus, as a treatment for the subject, a high emissivity paint is applied to the object to be examined (Patent Documents 4 and 5), a high emissivity network is used to improve the measurement accuracy (Patent Document 6), etc. Proposals have been made.

JP 2000-260800 A Japanese Patent No. 3372924 JP2007-95992 JP2003-226826A JP 2000-258371 A JP-A-9-113473

  In the above-mentioned Patent Document 4, a paint containing a pigment, a solvent and a dispersant is applied to an object to be inspected, and a paint containing an inorganic white powder, particularly organic bentonite, is applied as the dispersant. It is disclosed that a graphite release material having a high absorption rate for light energy is applied to an inspection object. However, any of the methods disclosed in the above-mentioned patent documents requires an additional step of peeling the paint from the product, which is complicated and inefficient, and increases the inspection work time and the inspection cost. Furthermore, in Patent Document 6, for example, a work of attaching a stainless steel mesh of about 80 mesh to the object to be inspected and press-contacting the object to be inspected is required, and in the case of a complicated shape object, it is difficult to hold it in accordance with the outer shape. In addition, the infrared emissivity is lowered by the wire mesh itself, and there is a problem that it is difficult to inspect the bonding state of the solder ball to the semiconductor product substrate with good accuracy.

  The present invention has been made in view of the above-described conventional problems, and one object of the present invention is to quickly inspect a large amount of target products while having a simple configuration, and to perform semiconductor processing of solder balls with high accuracy. An object of the present invention is to provide a method for inspecting a bonding state of a solder ball to a semiconductor product substrate and an inspection system thereof that can realize a bonding state inspection to the substrate.

In order to achieve the above object, the present invention is a method for inspecting the bonding state of a solder ball formed on a semiconductor product substrate to the product substrate, a heating step of heating the solder ball mounting substrate surface,
A cooling process for cooling the heated solder ball mounting substrate surface, a detection process for detecting infrared rays on the solder ball being cooled and the board in the vicinity of the solder ball, and a thermal energy distribution data based on the detected amount of infrared rays. Heat quality made of a synthetic resin or synthetic rubber having elasticity before heating to the cooling process after heating the solder ball mounting board surface in the heating process. Infrared high emissivity medium consisting of a heat-resistant thin film with a surface roughness of (heat-resistant thin film surface roughness> solder ball surface roughness) is detachably coated on the surface of the solder ball mounting substrate and subjected to negative pressure bonding A method for inspecting a bonding state of a solder ball to a semiconductor product substrate, characterized by comprising the step of:

The present invention also relates to a system for inspecting the bonding state of a solder ball formed on a semiconductor product substrate to the product substrate, a heating means (12) for heating the solder ball mounting substrate surface H, and the heated solder ball mounting substrate. The cooling means (14) for cooling the surface, the detecting means (16) for detecting infrared rays on the solder ball 24 being cooled and the substrate in the vicinity of the solder balls, and the thermal energy distribution data based on the detected amount of infrared rays, A quality judgment means (18) for judging the quality of the bonded state to the board, and a heat-resistant thin film made of synthetic resin or synthetic rubber having elasticity before heating and cooling the solder ball mounting board surface in the heating process. There the surface roughness is made of a heat resistant film 38 is (heat resistance thin film surface roughness> the solder ball surface roughness), the removably to the solder ball mounting substrate surface A cemented state inspection system 10 to the semiconductor product substrate solder balls infrared high emissivity medium, comprising the to be.
Detachable infrared high radiation including a heat-resistant thin film that is detachably coated on the solder ball mounting board surface before the solder ball mounting board surface is heated in the heating process and the heated solder ball mounting board surface is cooled in the cooling process. Since the heat-resistant thin film is detachably covered by the generation means, and then cooling and infrared detection are performed, detection can be performed with the infrared emissivity from the substrate increased, and the solder ball bonding state based on high-resolution energy distribution data The quality of the product is accurately determined. And the finished product can be used as it is by detaching the heat-resistant thin film from the surface. A heat-resistant thin film is a polymer film material that has a non-mirror surface roughness compared to solder balls, and is required to have a certain range of heat resistance, thickness, stretchability, thermal conductivity, etc. It is done. Since the heat-resistant thin film is tightly coated on the surface of the solder ball mounting substrate immediately after being heated, for example, heat resistance of 90 ° C. or higher is required and the film thickness is preferably 0.1 mm or less. This is because, for example, if the film thickness is too thick even if excellent in stretchability and thermal conductivity, thermal diffusion occurs, and if this becomes significant, the infrared energy level emitted to the outside is lowered. Examples of the material for the heat-resistant thin film include silicon rubber, polyurethane rubber, and rubber-based organic film. Since the heat-resistant thin film 38 is set so that the temperature to be inspected is, for example, about 80 ° C. or less by being heated by a heating device, the heat-resistant thin film 38 is preferably a material having heat resistance characteristics that can withstand at least 90 ° C. More specifically, the material may withstand a temperature of about 80 ° C. Further, it is preferable that the tensile strength is about 9.8 (MPa) as stretchability. About the attachment or detachment coating | cover of the heat resistant thin film to the solder ball mounting board | substrate surface, as long as it has the function, it can set arbitrarily about a specific mechanical structure and a moving system. For example, a detachable gripping mechanism that detachably grips the end side of the heat-resistant thin film may be prepared, and the entire ball mounting substrate surface may be covered while moving it in the horizontal direction or the vertical direction.

At that time, while the solder ball mounting substrate 22A is held on the base body 46, the infrared high emissivity medium is coated on the base body 46, and in this state, negative pressure suction means is applied to the entire uneven portion of the solder ball mounting substrate surface H. It is preferable to have a base device 40 for negatively pressure-bonding the infrared high emissivity medium in a close contact state by 42.

Further, the base device 40 has a gap G between the base body 46 and the solder ball mounting substrate 22A in a state where the infrared high emissivity medium is placed so as to cover the entire solder ball mounting substrate surface H. It is preferable to have an in-base suction path 52 for negatively pressure-bonding the infrared high emissivity medium in a close contact state with respect to the entire uneven portion of the solder ball mounting substrate surface H by the negative pressure driving source 42.

Furthermore, the base in the suction passage 52 is in a state of being placed on the ball mounting substrate surface H solder infrared high emissivity medium, so as to communicate with the gap 54 between the solder ball mounting substrate surface with the infrared high emissivity medium It is good to be provided. Further, it is more preferable that the annular airtight member 50 is protruded upward from the base body 46 so that the entire solder ball mounting board is accommodated in the state where the semiconductor product substrate 22A is held on the base body 46.

  Moreover, it is good that the film thickness of a heat resistant thin film is 0.02 mm-0.1 mm, and infrared energy radiation efficiency can be improved, without accompanying the radiation energy loss by thermal diffusion.

  Further, it is preferable that the heat resistant thin film has a heat resistant characteristic capable of withstanding at least 90 ° C.

  According to the method for inspecting the bonding state of the solder ball to the semiconductor product substrate of the present invention, the method for inspecting the bonding state of the solder ball formed on the semiconductor product substrate to the product substrate is a heating step of heating the surface of the solder ball mounting substrate. A cooling process for cooling the heated solder ball mounting substrate surface, a detection process for detecting infrared rays on the solder balls being cooled and the board in the vicinity of the solder balls, and heat energy distribution data based on the detected amount of infrared solder. A pass / fail judgment step for judging pass / fail of the bonding state of the ball to the substrate, and after heating the solder ball mounting substrate surface in the heating step, before moving to the cooling step, an infrared high emissivity composed of a heat-resistant thin film Infrared energy amount of solder ball because it is equipped with a process to detachably cover the surface of the solder ball mounting board and press the negative pressure The quality determination of the joint of the solder ball due to the energy distribution image with together performed with high precision, without the inspection after completion of the separating operation, such as during the paint coating, thereby improving the inspection efficiency.

  Further, according to the system for inspecting the bonding state of the solder ball to the semiconductor product substrate of the present invention, the system for inspecting the bonding state of the solder ball formed on the semiconductor product substrate to the product substrate is used to heat the surface of the solder ball mounting substrate. Heating means, cooling means for cooling the heated solder ball mounting substrate surface, detection means for detecting infrared rays on the solder balls being cooled and the board in the vicinity of the solder balls, and thermal energy distribution data based on the detected amount of infrared rays The solder ball mounting board surface is detachably coated on the solder ball mounting board surface before heating and cooling the solder ball mounting board surface in the heating process. A detachable infrared high radiation generation means including a heat-resistant thin film. The product can be inspected quickly, and the solder balls can be inspected in a non-contact manner with high precision. At the same time, the inspected product can be used in actual equipment without any special treatment. The final inspection efficiency can be improved.

  In addition, the above-described system for inspecting the bonding state of the solder ball to the semiconductor product substrate covers the surface of the solder ball mounting substrate in such a state that the solder ball mounting substrate is held on the base body and the heat resistant thin film is coated thereon. Since the entire surface of the concavo-convex portion has a base device for negatively pressure-bonding the heat-resistant thin film in a close-contact manner by a negative pressure suction means, simply placing the heat-resistant thin film on the base body and sucking the negative pressure Infrared energy radiation efficiency by ensuring the thermal conductivity and preventing thermal diffusion as the thin film can be adhered to the entire surface of the board and each solder ball so as to eliminate the gap between each solder ball on the board and the heat-resistant thin film Can be improved.

  In addition, the base device is soldered by a negative pressure drive source through a gap between the base body 46 and the solder ball mounting substrate in a state where a heat resistant thin film is placed so as to cover the entire surface of the solder ball mounting substrate. By adopting a structure that has a suction path in the base that negatively pressure-bonds the heat-resistant thin film in close contact with the entire uneven surface of the ball mounting substrate surface, the heat-resistant thin film is simply placed on the base body and sucked with negative pressure. The thin film can be effectively adhered to the entire surface of the substrate and each solder ball so as to eliminate the gap between each solder ball on the substrate and the heat-resistant thin film.

  Further, the suction path in the base is configured to communicate with the gap between the heat resistant thin film and the solder ball mounting substrate surface in a state where the heat resistant thin film is placed on the solder ball mounting substrate surface. Then, simply place the heat-resistant thin film on the base and suck the negative pressure over the entire surface of the board and each solder ball so that there is no gap between each solder ball on the board and the heat-resistant thin film. It can be brought into close contact effectively.

  In addition, since the base airtight member is protruded upward from the base body so that the entire solder ball mounting board is accommodated inside the semiconductor product board held on the base body, it is simply heat resistant. The thin film is effectively adhered over the entire surface of the substrate and each solder ball so that the gap between each solder ball on the substrate and the heat-resistant thin film is eliminated simply by placing the conductive thin film on the base and sucking it under negative pressure. Can be made.

  In addition, the heat-resistant thin film has a thickness of 0.02 mm to 0.1 mm to ensure good thermal conductivity and elasticity while preventing thermal diffusion from the solder balls and the substrate in the thin film. sell.

  In addition, when the heat-resistant thin film has a heat-resistant characteristic capable of withstanding at least 90 ° C., it is possible to continuously continue the process for improving the infrared energy radiation characteristic on the premise of rapid heating at a close distance.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. FIG. 1 to FIG. 6 show an embodiment of the present invention, and FIG. 1 is a configuration diagram of a bonding state inspection system 10 for a solder ball to a semiconductor product substrate according to the embodiment of the present invention. A method for inspecting the bonding state of the solder ball to the semiconductor product substrate will also be described.

  A solder ball bonding state inspection system (hereinafter referred to as a “bonding state inspection system”) 10 according to the embodiment includes a heating device 12, a cooling device 14, a detection device 16, and a control determination device 18. And a detachable infrared high radiation generator 13.

  The solder ball is a ball-shaped alloy joint having a diameter of, for example, about 0.6 mm, which occurs in a solder joint process with a substrate electrode portion of a solder ball-mounted semiconductor product such as a BGA type package or a CSP type package. In FIG. 1, a product 22 to be inspected such as a BGA type package or a CSP type package (hereinafter referred to as “product”) with the solder ball mounting surface H facing upward while being positioned on a tray 20 moved by an XY table (not shown). ") Is arranged. A large number of solder balls 24 are formed on the solder ball mounting surface H side of the product 22.

  In the embodiment, the heating device 12 is a heating unit that is a first temperature field forming unit of an integrated circuit device substrate to be inspected, which heats a solder ball mounting surface of a semiconductor product mounted with a solder ball. For example, it comprises a hot air blower that blows hot air onto the ball mounting surface of the substrate to be inspected. The hot air blower includes a fan (not shown) for supplying air, an air outlet 26 for guiding hot air against the ball mounting surface of the substrate to be inspected, and a heater 28 for heating the air before the air is blown from the air outlet. I have. The blower outlet and the product substrate solder ball mounting surface are, for example, a close distance of about 7 cm, and the heating function is effectively generated by directly heating only the solder ball mounting surface. In addition, the thermal response speed is fast, and inspection of the bonding state between each solder ball and the substrate electrode portion can be performed in a short time. From the viewpoint of product utilization, it is preferable to heat the inspection object at a temperature at which the heated solder ball by the heating device does not melt, for example, in the range of 60 ° C to 150 ° C. More preferably, it is good to heat in the range of 70 to 80 degreeC. The heating time by the heating device 12 is preferably in the range of 1.0 second or more and 60 seconds or less. When the heating time is 1.0 second or less, heating of the solder balls is insufficient, and when the heating time is 60 seconds or more, the substrate in the vicinity of the solder balls is heated too much, which is not preferable. The heating time is controlled within 0.1 to 5 seconds by the control device 32. As the heating means, in addition to hot air blowing, for example, an infrared lamp or other heat ray irradiation lamp can be used.

  The cooling device 14 is a cooling means which is a second temperature field forming means of the integrated circuit device substrate to be inspected for cooling the solder ball mounting substrate surface heated by the heating device. It is comprised from the cold wind spraying apparatus which sprays compressed air or low temperature air to a mounting surface. The cold air blowing device includes a cold air supply supply source such as a pump and a fan (not shown), and a cooling air outlet 30 that guides the cooling air to blow against the ball mounting surface of the substrate to be inspected. Yes. The blower outlet 30 and the product substrate solder ball mounting surface H are close to each other, for example, about 7 cm, and the cooling function is effectively generated by directly cooling only the solder ball mounting surface. The cooling time by the cooling device 14 is preferably in the range of 0.1 second to 2 seconds. If the cooling time is 0.1 second or less, the solder ball and the substrate in the vicinity of the solder ball are not sufficiently cooled. If the cooling time is 2 seconds or more, the solder ball and the substrate in the vicinity of the solder ball are excessively cooled. Therefore, it is not preferable.

  The heating time and the cooling time are factors that can affect the accuracy and precision in the quality determination process described later. For example, if the heating time and the cooling time are set outside the above ranges, they may be reduced. In the present embodiment, since the cooling device 14 is constituted by a cold air spraying device, the cooling means does not require a coolant such as water or a low-temperature medium, and therefore is inexpensive without requiring a wide installation area. A solder ball bonding state inspection system can be provided.

  The detection device 16 is infrared detection means for detecting infrared rays on the solder ball being cooled by the cooling device and the substrate in the vicinity of the solder ball following the heating by the heating device, and an infrared sensor, for example, is used. The infrared detector 16 is a means for detecting infrared energy radiated from an object to be measured and measuring a temperature distribution based on the thermal energy distribution. The infrared energy distribution obtained by image processing can be displayed on a display and observed. It is good. In the present embodiment, the detection device 16 is configured by a device that quantitatively converts infrared energy into a temperature distribution and measures the temperature distribution, such as an infrared thermography. The detection device 16 is mechanically integrated into the cooling device 14. However, it may be movable independently by a separate body.

  The control determination device 18 measures the temperature distribution based on the energy distribution data based on the amount of infrared rays detected by the infrared detection means 16 and determines whether the solder ball is bonded to the substrate from the temperature distribution state. In the present embodiment, a control device 32 including a computer and a display device 34 for displaying the determination result are included. The display device 34 is also used for identification management of products to be inspected and for displaying other inspection management screens. The control device 32 can control devices such as the heating device 12, the cooling device 14, the infrared sensor 16, the display device 34, and the detachable infrared high-radiation generation device 13, which will be described later, via wires or wirelessly. It is connected and calculates the physical quantities necessary to achieve those functions, and controls the movement and functions as a whole. In particular, the energy data acquired by the infrared sensor 16 is processed to measure and generate temperature data, and a determination result using the temperature data is displayed on the display device 34.

  In the present invention, a characteristic feature is that the solder ball mounting board surface H is heated in the heating process, and is then removed from the solder ball mounting board surface H before being cooled by the cooling device 14. That is, the generation device 13 is arranged. The detachable infrared high radiation generator 13 includes a heat-resistant thin film 38 that is detachably coated on the solder ball mounting substrate surface H.

■ただし、Ｗ＝赤外線エネルギー、ε＝放射率、δ＝定数、Ｔ＝絶対温度。放射率（ε）は、（物体放射エネルギー）÷（黒体放射エネルギー）で定義される。 In the figure, the detachable infrared high radiation generator 13 raises the amount of infrared radiation from the solder ball mounting substrate surface H to a high level, and the final temperature distribution data based on the obtained infrared data determines whether the solder ball is joined or not. Reflect it with high accuracy. In other words, in general, when the quality of the solder ball bonding state of a semiconductor product with a solder ball is determined based on data based on the detection of the emitted infrared radiation, it is sufficient for the determination of the bonding state with high accuracy only by measuring the subject with the infrared sensor. It is difficult to generate a simple distribution image. In general, it is considered that infrared energy obtained by adding the energy emissivity of each object to the infrared energy of blackbody radiation is radiated from each object as shown in the following equation (1).

(2) where W = infrared energy, ε = emissivity, δ = constant, T = absolute temperature. The emissivity (ε) is defined by (object radiant energy) ÷ (black body radiant energy).

Of these emissivity characteristics, the rougher the surface of the object, the greater the emissivity and the smaller the specular surface. For this reason, the infrared energy level from the solder ball mounting substrate surface H including a large number of solder balls having a mirror-finished surface is low, and therefore it is difficult to perform pass / fail judgment with good accuracy from the obtained temperature distribution data.

  In this embodiment, the emissivity characteristic of infrared energy from the solder ball mounting substrate surface H is improved by the detachable infrared high radiation generator 13 before heating and cooling the solder ball mounting substrate surface in the heating process. Since cooling is performed as a state and infrared energy data is acquired in that state, the presence of cracks and cavities in the solder ball joint can be detected with high accuracy.

  In FIG. 2, the detachable infrared high radiation generator 13 includes a heat-resistant thin film 38, a base device 40, and a negative pressure suction device 42. The base device 40 receives the product substrate 22A whose surface of the solder ball mounting substrate has been heated in the heating process of the heating device, is placed on the XY table 44, and can move vertically and horizontally.

  The base device 40 holds the semiconductor product substrate 22A, covers the heat-resistant thin film 38 from above, and negatively press-bonds the heat-resistant thin film 38 to the solder ball mounting substrate surface H. In this state, the cooling device 14 This is a means for cooling the solder ball mounting substrate surface H by, and then removing the heat resistant thin film 38 from the solder ball mounting substrate surface H. In this embodiment, the base device 40 has a rectangular parallelepiped base body 46 having a flat surface at the upper end, and a recess 48 for positioning and arranging a product substrate 22A to be inspected that is recessed at the center of the upper surface. And. The material of the bottom wall of the recess of the base body 46 is made of a heat insulating material, and prevents heat diffusion from the solder ball mounting board. The recess of the base body 46 has an adhesive or suction surface for fixing the product substrate 22A. Further, as shown in FIG. 5, a rubber annular packing as an airtight member 50 is provided on the base body 46 so as to surround the product substrate 22 </ b> A disposed in the recess 48 on the upper surface of the base body 46. A part is projected upward from the upper surface of each of them and is arranged in an embedded form. When the airtight member 50 is sucked from the lower surface side of the product substrate 22 </ b> A in a state where the upper surface is covered with the heat resistant thin film 38 so as to cover the entire product substrate 22 </ b> A, the heat resistant thin film 38 having a large coefficient of friction is formed between the airtight member 50 and the airtight member 50. It is a negative pressure means for tightly contacting at the contact position and partitioning the entire gap including the gaps between the solder balls from the outside with an airtight member to make the pressure negative. A heat-resistant thin film may be placed on the airtight member and the airtightness may be maintained by sandwiching the heat resistant thin film from above the heat resistant thin film.

  Further, the base device 40 has a base suction path 52. The suction path 52 in the base is a base for negatively pressure-bonding the heat-resistant thin film on the solder ball mounting substrate surface H in a state where the heat-resistant thin film is placed so as to cover the entire solder ball mounting substrate surface H. FIG. 3 shows one or a plurality of negative pressure suction paths provided between the wall surface 48A of the recess 48 and the outer contour of the product substrate 22A in a state where the product substrate 22A is disposed in the recess 48. , The intermediate passage 56 formed in the bottom surface of the product substrate 22 </ b> A, that is, in the bottom wall of the recess 48, and the recess hole 58 drilled in the center of the bottom wall of the recess 48. And a base passage 62 formed in the base body so as to communicate with the external suction hose 60. When a negative pressure suction device 42 composed of, for example, a vacuum pump as a suction drive means connected to the external suction hose 60 is driven by covering the heat resistant thin film 38 larger than the annular packing 50 from above, a gap between the suction paths 52 in the base is obtained. 54 communicates with the negative pressure suction route by the vacuum pump and also communicates with the gap G between the heat-resistant thin film 38 and each solder ball 24 shown in FIG. The adhesion between the heat-resistant thin film 38 and each solder ball 24 is improved. That is, the in-base suction path 52 passes through the gap 54 between the base body 46 and the solder ball mounting substrate 22A in a state where the heat-resistant thin film 38 is placed so as to cover the entire solder ball mounting substrate surface H. Then, the heat-resistant thin film 38 is negatively pressure-bonded in a close contact state over the entire uneven portion of the solder ball mounting substrate surface H by the negative pressure drive source 42. Thereby, infrared energy from the solder ball surface can be efficiently conducted by the heat-resistant thin film 38 and radiated to the outside.

  The heat-resistant thin film 38 detachably covers the solder ball mounting substrate surface H, and when the infrared high emissivity state is generated after heating, the solder ball mounting substrate surface H is covered and adhered in negative pressure. After being cooled by the cooling device and acquiring infrared energy data by the infrared detecting device 16 such as an infrared sensor at the same time, it is detached from the substrate surface H and used as a product without applying any processing to the inspected product 22 after the inspection. It is one element of a detachable infrared high radiation generation device that is made possible. The heat-resistant thin film 38 is formed of an ultra-thin film-like material made of a synthetic resin, synthetic fiber, or synthetic rubber thin film having heat resistance and a certain degree of elasticity. The heat-resistant thin film 38 is a polymer thin film having a predetermined thickness and preferably has flexibility and rubber elasticity in addition to heat resistance. For example, a synthetic resin as a material of the heat-resistant thin film 38 can be selected from either a thermosetting resin or a thermoplastic resin. Examples of the thermosetting resin include phenol resin, melamine resin, epoxy resin, silicon resin, alkyd resin, polyurethane resin, and the like. The thermoplastic resin includes polyethylene resin, polystyrene resin, ABS resin, polypropylene, vinyl chloride resin, methacrylic resin, polyethylene terephthalate, polycarbonate, polyamide, polyimide, polyacrylonitrile, fluororesin, thermoplastic elastomer, and others. Synthetic rubbers include butadiene rubber, chloroprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluorine rubber, and silicone rubber. Moreover, it is good to comprise with the heat-resistant elastic film which has the organic polymer which consists of these rubber | gum as a main component. More preferably, for example, silicon rubber, polyurethane rubber, rubber organic film or the like may be used. Since the heat-resistant thin film 38 is set so that the temperature to be inspected is, for example, about 80 ° C. or less by being heated by a heating device, the heat-resistant thin film 38 is preferably a material having heat resistance characteristics that can withstand at least 90 ° C. More specifically, the material may withstand a temperature of about 80 ° C. Moreover, the tensile strength should just be about 9.8 (MPa) as stretchability. The thickness of the thin film is related to the stretchability and the conductivity of the heat component. For example, the thickness of the thin film is preferably in the range of 0.02 mm to 0.1 mm, more preferably in the range of 0.02 mm to 0.05 mm. There should be. The thermal conductivity is preferably 0.1 W / (m · K) or more.

Next, while referring to FIGS. 7 to 11 together with the operation of the apparatus of the embodiment, the method for inspecting the bonding state of the solder ball to the semiconductor product substrate of the present invention will be described. The semiconductor product 22 to be inspected with the solder balls 24 mounted on the substrate 22A is transported to the heating device in a state where the solder ball mounting surface H is placed on the upper surface and the recessed portion 48 of the base body 46 made of a heat insulating material is installed. . 1, the distance from the heating device to the product substrate 22A to be inspected is set to about 7 cm when the outlet temperature is 180 ° C. or higher, and hot air is blown and heated toward the solder ball mounting surface H of the substrate. When the solder ball substrate rises to about 80 ° C., the product 22 is placed on a predetermined positioning portion of the recess 48 of the base body 46 of the detachable infrared high radiation generator 13, and the thin film vertical movement mechanism shown in FIG. The heat-resistant thin film 38 is lowered through 64 in a state where the heat-resistant thin film 38 is vertically oriented, and is placed on the upper surface of the base body 46 (see FIG. 3). In the thin-film vertically moving mechanism 64, for example, is vertically driven in a state developed in the horizontally holding the heat-resistant thin film 38. At this time, the heat resistant thin film 38 is covered with an outer contour larger than the annular packing 50 and larger than the outer shape of the annular packing. In this state, when the vacuum pump as the negative pressure suction device 42 is driven and negative pressure suction is performed, the upper surface of the substrate 22A placed in the recess is substantially flush with the upper surface of the base body 46, so the negative pressure is Then, the air in the gap P is sucked to bring the heat-resistant thin film 38 into close contact with the upper surface of the base body. At this time, as indicated by the broken line in FIG. 4, the air in P and the gap G flows from the gap 54 between the corner of the substrate and the corner of the recess, and passes through the intermediate passage 56, the recess hole 58, and the base passage 62. It is sucked to the suction drive source side. Furthermore, this negative pressure is also applied to the gap G between the heat resistant thin film 38 and each solder ball 24 in FIG. 6, and the heat resistant thin film is applied over substantially the entire surface of each solder ball 24 as shown in FIG. 6B. 38 is in close contact. In this state, the solder ball mounted semiconductor product is conveyed to the cooling device. Then, for example, when low-temperature air whose outlet temperature is set to 10 ° C. or less is blown out to the same surface as the heating surface by the cooling device 14, an instantaneous temperature change occurs, and the infrared energy amount corresponding to this temperature change is determined by the infrared sensor. Detect with. In the solder ball mounted semiconductor product, the infrared sensor as an infrared detecting device is placed on the solder ball 24 on the solder ball mounting surface and on the surrounding product substrate 22A from just before the solder ball mounting surface H is cooled by the cooling device 14 until the end of cooling. Measure the temperature corresponding to the infrared energy. The measuring time of the cooling device 14 is controlled by the control determination device 18 within 0.1 to 1.0 seconds as the cooling time. The infrared detector 16 is controlled by the control determination device 18 so as to detect the temperature on the solder ball 24 and the product substrate 22A from immediately before the start of cooling by the cooling device 14 until the end of cooling. The temperature on the solder ball 24 and the product substrate 22A in the vicinity of the solder ball from immediately before the start of cooling to the end of cooling is transferred from the infrared detection device 16 to the control determination device 18. At this time, the temperature on the product substrate 22A in the vicinity of the solder ball is measured at the center between the adjacent solder balls. The data transferred from the infrared detection device 16 is converted from energy distribution data to temperature distribution data in the control device 32 of the control determination device 18, and a determination result signal based on the data is transmitted to the display device 34. Highly accurate pass / fail judgment of the solder ball joint by the distribution of infrared energy of the product substrate 22A is realized in a short time. When there are cracks or cavities in the solder ball joint, the thermal conductivity of that part is low, and the surface temperature of those defective parts appears locally higher than the ambient temperature, but following heating, When cooled immediately after heating, the temperature of the ball having a poorly bonded portion appears low.

Specifically, in FIG. 1, the infrared information of the temperature on the product substrate 22A in the vicinity of the solder ball 24 on the solder ball mounting surface immediately before the start of cooling until the end of cooling detected by the infrared detector 16 is detected simultaneously with the detection. Automatically transferred from the device 16 to the control determination device 18. As shown in FIGS. 7 and 8, the solder ball 241 with good bonding of the solder ball mounted product substrate heated by the heating means undergoes a large heat transfer 82 from the solder ball to the substrate. On the other hand, in the poorly bonded solder ball 243, a small heat transfer 84 occurs from the solder ball to the product substrate 22A, and further, the heat transfer that is not transmitted to the product substrate 22A at the defective portion (bonded defective portion between the solder ball and the substrate electrode) 83. Since 86 occurs, heat accumulates in the solder balls themselves. Furthermore, in the case of cooling, as shown in FIG. 8, in the case of the solder ball 24, since there is a large heat transfer 88 from the lower layer to the solder ball via the electrode portion 25, the temperature on the solder ball 241 with good bonding is the heat generated by the cooling. Even if there is the movement 90, the temperature on the solder ball 241 with good bonding is maintained at a certain level or higher. However, in the case of the poorly bonded solder ball 243, only a small heat transfer 92 from the lower layer to the poorly bonded solder ball 243 occurs via the electrode portion 25. After that, the temperature on the solder ball 24 drops to a temperature below a certain level. Further, the temperature on the semiconductor substrate 22A in the vicinity of each solder ball is different from the temperature on each solder ball, but is heated and cooled to the same extent, and each solder is heated at a temperature on the semiconductor substrate 22A in the vicinity of each solder ball. By using a value obtained by dividing the temperature on the ball (non-dimensional temperature), the influence of temperature deviation in the sample can be eliminated. In FIGS. 7 and 8, reference numeral 80 denotes heat transfer to the solder balls given by the heating means, 81 denotes heat transfer to the board given by the heating means, 83 denotes a defective joint between the solder balls and the board electrodes, Reference numeral 85 denotes heat transfer from the substrate taken away by the cooling means.

  The quality determination procedure is shown below. As shown in FIG. 9, the temperature on each solder ball at the end of cooling in process 1 or immediately before and at the end of cooling and on the product substrate 22A in the vicinity of each solder ball is extracted. Next, in the process 2, the temperature on each solder ball is divided by the temperature on the product substrate 22A in the vicinity of each solder ball to calculate the dimensionless temperature. Finally, in the process 3, the non-dimensional temperature obtained in the process 2 is compared with a preset reference value, and quality is determined. FIG. 10 and FIG. 11 are graphs in which the horizontal axis represents the ball number and the vertical axis represents the temperature ratio or the temperature ratio difference between the solder balls at the start and end of cooling and the product substrate 22A near each solder ball. is there.

As a pass / fail judgment method, when using the non-dimensional temperature at the end of cooling as shown in FIG. 10, the non-dimensional temperature 94 of the solder ball with good bonding state shows a value higher than a preset value 96, The dimensionless temperature 98 of the solder ball having a poor bonding state is lower than a preset value 96 . Further, as shown in FIG. 11, when using the dimensionless temperature difference at the start of cooling and at the end of cooling, the dimensionless temperature 102 of the solder ball with good bonding state shows a value lower than a preset value 104, dimensionless temperature 106 of the solder balls bonded state failure indicates a higher value 104 previously set value. Therefore, whether or not the joining state is good can be determined without being affected by the temperature deviation, and if the solder balls are numbered in advance, it is possible to easily detect which solder ball is in a defective state.

When the non-dimensional temperature at the end of cooling is used, the non-dimensional temperature 94 of the solder ball with good bonding state shows a value close to 1.0, and the non-dimensional temperature 98 of the solder ball with poor bonding state is 0.95. The following values are shown. Therefore, a preset value is determined between 1.0 and 0.95, and when it is larger than the preset value, it is determined that the solder ball is well bonded, and when it is small, it is determined as a poorly bonded solder ball.

A product determined as a well-bonded product from the good / bad determination described above is discharged to a well-bonded product location, and a product determined to be a poorly bonded product is discharged to a poorly bonded product location.

As described above, in the method for inspecting the bonding state of a solder ball to a semiconductor product substrate and the inspection system thereof according to the present invention, the surface of the solder ball mounted substrate is heated by the heating means, and the heated solder ball mounted substrate surface is cooled. Since the operation is performed by the detachable infrared high radiation generation means including the heat-resistant thin film that is detachably coated on the surface of the solder ball mounting board before cooling by means, the solder ball of the solder ball by the energy distribution image by the amount of infrared energy of the solder ball is used. It is possible to determine the quality of the bonded portion with high accuracy and to improve the inspection efficiency without accompanying a peeling work after the inspection at the time of applying the paint.

A sample product is prepared by forming three sets of a solder ball mounting surface in which a pair of ball solder portions having a good bonding state and a defective one are arranged at adjacent positions, and this is used for the base device 40 described above. Set in the concave portion 48, heated with hot air, heated with compressed air, cooled, and in a mirror state where the heat-resistant thin film is not coated with an infrared camera, and in a state where the heat-resistant thin film is coated and adhered, respectively The temperature change was measured after cooling the temperature on the sample solder ball and the temperature on the substrate for each of the three sets of good products and defective products. FIGS. 12 to 14 are comparative example measurement value graphs performed on a sample product in a state having a mirror-like surface that does not use a heat-resistant thin film, and FIGS. 15 to 17 illustrate a case where the solder ball mounting surface is coated with the heat-resistant thin film. The measurement value graph of the Example performed in the state which made the heat resistant thin film adhere to the whole solder ball mounting surface by negative pressure adsorption | suction is shown.

[Measuring equipment]
Specification heating temperature of the hot air generator at the time of heating: a function capable of generating and heating hot air of 120 ° C. or higher from the outlet, and a function of heating the subject surface to 80 ° C. or higher within 5 seconds Have Rated flow: 100 L / min. Aperture / distance: A bore / distance that can heat the entire subject without bias. The distance from the outlet to the subject was set to about 4 cm.
Specification pressure of cooling device during cooling: A compressor capable of maintaining a pressure of 0.5 MPa or more, and air compressed as it was was used for cooling. Air outlet: The shape of the infrared camera field of view can be cooled at a time, and it was set at a position separated to the extent that the cooling bias could not be biased within the infrared camera field of view. The distance from the subject was set to about 1 cm.
Infrared camera detection wavelength: 8-14 μm
Detection temperature range: The one capable of detecting at least 20 to 150 ° C was used.
Installation conditions: 5.6 cm (fixed) from subject to lens, visual field range, 256 (vertical) × 324 (horizontal), and spatial resolution of at least 0.1 mm (per pixel) were used.
The subject sample product is a product with about 400 balls and is intended to fit within one field of view of an infrared camera.
[Measurement procedure]
In a state in which hot air blowing is heated from the surface of the subject for 5 seconds at the outlet temperature of 120 ° C., the heat resistant thin film is coated, cooled, transported to the measurement position, and the vacuum pump is driven to bring the heat resistant thin film into close contact. When the pressure fell below a certain value, the temperature was measured while the suction was continued. The comparative example was cooled for 0.6 seconds, the example was cooled for 0.4 seconds, and the temperature was measured for each of the three balls and the entire substrate in the time zone from the start of cooling over the required time after the end of cooling.
[Evaluation by graph]
In this embodiment, the detected temperature of the bonded good balls is generally higher than that of the defective balls. In the measurement values of the comparative examples in FIGS. 12 to 14, the temperature range by detection is about 32 ° C. to 36 ° C., whereas in the measurement values of the examples, the detection is in the region of about 68 ° C. to 78 ° C. From the correlation between the energy level and the surface temperature, it can be seen that there was a significant improvement in infrared emissivity when the heat-resistant thin film was used. In the sample products of the comparative examples in FIGS. 12 to 14, there is a large change in the detected temperature difference between the non-defective balls and the defective balls, and there is a portion where there is a large variation or a temperature inversion state that is assumed to be an erroneous measurement. On the other hand, in the sample products of the examples of FIGS. 15 to 17, the detected temperature difference between the non-defective balls and the defective balls becomes a very gradual change and changes with a substantially constant difference. As a result, it is understood that, in combination with the detection temperature region becoming higher, the bonding quality and defect detection resolution are improved, and the quality determination can be performed with high accuracy. That is, when the ball mounting surface of a solder ball mounting product is cooled immediately after heating, the temperature is changed on the ball mounting surface side at that time by cooling with the heat-resistant thin film applied as in the embodiment after heating. By detecting, a required reference value is set based on the detected data, and the quality of the ball joint portion is determined with high accuracy by comparison with the reference value. When performing determination processing for a plurality of solder ball mounted products, the devices are arranged in parallel for the heating process, the heat-resistant thin film attachment / detachment process, the cooling process, and the detection process of the above-described embodiment, and the process proceeds simultaneously. It can be made to move.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration explanatory diagram of a bonding state inspection system for solder balls to a semiconductor product substrate according to an embodiment of the present invention. It is a longitudinal cross-sectional explanatory drawing of the base apparatus of FIG. FIG. 3 is an enlarged vertical cross-sectional explanatory view of a main part of the base device of FIG. 2. FIG. 4 is an enlarged perspective view of a recess of the base device of FIG. 3. It is a plane explanatory view of the base body of the base device of FIG. (A), (b) is operation | movement explanatory drawing at the time of coating | covering a heat resistant thin film on the product board | substrate mounted in the recessed part, and attracting | sucking a negative pressure. It is effect | action explanatory drawing which shows the movement of a thermal energy. It is effect | action explanatory drawing which shows the movement of a thermal energy. It is the flowchart figure which showed the procedure of quality determination. It is the figure which illustrated the dimensionless temperature at the time of completion | finish of cooling. It is the figure which illustrated the dimensionless temperature difference just before cooling and the time of completion | finish of cooling. It is a comparative example measured value graph which was performed in the state which has the mirror-like surface which does not use a heat resistant thin film. It is a comparative example measured value graph which was performed in the state which has the mirror-like surface which does not use a heat resistant thin film. It is a comparative example measured value graph which was performed in the state which has the mirror-like surface which does not use a heat resistant thin film. It is the Example measured value graph which carried out in the state which coat | covered the heat resistant thin film on the solder ball mounting surface, and made the heat resistant thin film adhere to the whole solder ball mounting surface by negative pressure adsorption. It is the Example measured value graph which carried out in the state which coat | covered the heat resistant thin film on the solder ball mounting surface, and made the heat resistant thin film adhere to the whole solder ball mounting surface by negative pressure adsorption. It is the Example measured value graph which carried out in the state which coat | covered the heat resistant thin film on the solder ball mounting surface, and made the heat resistant thin film adhere to the whole solder ball mounting surface by negative pressure adsorption.

DESCRIPTION OF SYMBOLS 10 Joining state inspection system of solder ball to semiconductor product substrate 12 Heating device 13 Detachable infrared high radiation generator 14 Cooling device 16 Detection device 18 Control judgment device 22 Product to be inspected 22A Product substrate 24 Solder ball 241 Solder ball 243 with good bonding Solder balls with poor bonding 32 Control device 34 Display device 36 Detachable infrared high radiation generator 38 Heat resistant thin film 40 Base device 42 Negative pressure suction device 46 Base body 48 Recess 50 Ring packing 52 Intra-base suction path 54 Clearance H Solder ball Mounting surface G Gap between heat-resistant thin film and each solder ball

Claims (8)

A method for inspecting the bonding state of a solder ball formed on a semiconductor product substrate to the product substrate,
A heating process for heating the solder ball mounting substrate surface;
A cooling step for cooling the heated solder ball mounting substrate surface;
A detection step of detecting infrared rays on the solder ball being cooled and the substrate in the vicinity of the solder ball;
A pass / fail judgment step for judging pass / fail of the bonding state of the solder balls to the substrate by thermal energy distribution data based on the detected amount of infrared rays,
After heating the solder ball mounting substrate surface in the heating process and before moving to the cooling process, it is a heat-resistant thin film made of a synthetic resin or synthetic rubber having elasticity, and its surface roughness is (heat-resistant thin film surface roughness> solder A solder ball having a process of detachably coating a solder ball mounting substrate surface with an infrared high emissivity medium comprising a heat resistant thin film having a ball surface roughness) to a semiconductor product substrate Bonding state inspection method. A system for inspecting the bonding state of a solder ball formed on a semiconductor product substrate to the product substrate,
Heating means for heating the solder ball mounting substrate surface;
Cooling means for cooling the heated solder ball mounting substrate surface;
Detection means for detecting infrared rays on a solder ball being cooled and a substrate in the vicinity of the solder ball;
A pass / fail judgment means for judging pass / fail of the bonding state of the solder balls to the substrate based on thermal energy distribution data based on the detected amount of infrared rays;
Before heating and cooling the solder ball mounting board surface in the heating process, it is a heat-resistant thin film made of synthetic resin or synthetic rubber having elasticity, and its surface roughness is (heat-resistant thin film surface roughness> solder ball surface roughness And an infrared high emissivity medium that is detachably coated on the surface of the solder ball mounting substrate, and a solder ball bonding state inspection system to the semiconductor product substrate. The solder ball mounting substrate to cover said infrared high emissivity medium thereon while holding the base body, in that state, the infrared high emissivity medium by negative pressure suction means for the entire uneven portion of the solder ball mounting substrate surface 3. A system for inspecting a bonding state of a solder ball to a semiconductor product substrate according to claim 2, further comprising a base device for negatively pressure-bonding the solder ball in a close contact state. The base device is a solder ball that is driven by a negative pressure drive source through a gap between the base body and the solder ball mounting substrate in a state where an infrared high emissivity medium is placed so as to cover the entire surface of the solder ball mounting substrate. 4. A bonding state of a solder ball to a semiconductor product substrate according to claim 2, further comprising: a suction path in the base for negatively pressure-bonding the infrared high emissivity medium in a close contact state with respect to the entire uneven portion of the mounting substrate surface. Inspection system. The suction passage base is in a state of being placed on the ball mounting substrate surface solder infrared high emissivity medium is provided so as to communicate with the gap between the solder ball mounting substrate surface with the infrared high emissivity medium The system for inspecting the bonding state of a solder ball to a semiconductor product substrate according to claim 4.   3. An annular hermetic member projecting upward from the base body so that the entire solder ball mounting board is accommodated inside the semiconductor product board while the base body is held on the base body. 6. A system for inspecting a bonding state of a solder ball according to any one of claims 5 to a semiconductor product substrate.   7. The system for inspecting the bonding state of a solder ball to a semiconductor product substrate according to claim 2, wherein the heat-resistant thin film has a thickness of 0.02 mm to 0.1 mm. The system for inspecting the bonding state of a solder ball to a semiconductor product substrate according to any one of claims 2 to 7, wherein the heat-resistant thin film has a heat-resistant characteristic capable of withstanding at least 90 ° C.

Images