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    • 专利摘要:
    PURPOSE: An interfacial adhesive strength evaluation specimen and method is provided to evaluate interfacial adhesive strength in a convenient and accurate manner, while preventing sudden crack propagation. CONSTITUTION: An interfacial adhesive strength evaluation specimen comprises a first region formed of a substrate and attached to a jig of a load applying device; and a second region formed by laminating a material different from the material of the substrate and a reinforcement member made of a material same with the material of the substrate, wherein the second region receives load applied from the load applying device. An interfacial adhesive strength evaluation method comprises a first step of coupling a reinforcement member to the second region; a second step of attaching the first region of the specimen to a jig; a third step of applying load to the second region; a fourth step of measuring length of crack generated between the substrate and the material of the second region; and a fifth step of calculating a critical energy using the relation between the load and length of crack.
    公开号:KR20020086019A
    申请号:KR1020010025610
    申请日:2001-05-10
    公开日:2002-11-18
    发明作者:권동일；정증현
    申请人:권동일；
    IPC主号:
    专利说明:

    Interfacial bond strength test specimen and its interfacial bond strength evaluation method {SPECIMEN AND TEST METHOD OF INTERFACIAL ADHENSIVE STRENGTH}
    [16] The present invention relates to an interface bonding strength evaluation specimen and an interface bonding strength evaluation method, and more specifically, to an interface bonding strength evaluation specimen and its interface bonding strength evaluation, which makes it easy to evaluate the interface bonding strength of the specimen by a standardized analysis method. It is about a method.
    [17] In general, in the thin film and packaging technology, it is very important to accurately evaluate the interfacial bonding strength between different materials joined by a coating material, a brazing material, a welding material, a solder material, and the like in the development of materials or packaging packaging technology.
    [18] These interfacial bond strengths cannot be quantified because of the experimental and theoretical difficulties in joining different materials. Accordingly, a number of methods have been developed and used empirically to obtain the interface bonding strength through a number of studies and experiments. In particular, research on the development of interfacial fracture mechanics test, which applies the fracture mechanics test and evaluates how resistant the interface is when cracks propagate, is active.
    [19] Referring to FIGS. 6 to 10, a method for evaluating the interface bonding strength, which is the degree to which the interface resists the growth of cracks, using the interface fracture energy test method will be described with reference to FIGS. 6 to 10.
    [20] As shown in FIG. 6, the specimen 51 used to obtain the interfacial bonding strength is a rod-shaped substrate 53 to evaluate the bonding strength, and is bonded in one region along the longitudinal direction of the substrate 53. Thin film 55. The specimen 51 is divided into a first region (I) consisting only of the substrate 53 and a second region (II) having the thin film 55 attached to the substrate 53. In the second region of the specimen 51, a crack is formed between the substrate 53 and the thin film 55 to perform a test for obtaining interfacial bonding strength, and this crack is called a precrack.
    [21] In order to measure the bonding strength of the specimen 51, a load application system 60 is used to fix the specimen 51 and apply a load. The load application system 60 is a specimen as shown in FIG. The test piece fixing part 61 for fixing the second area II of the part 51, the load applying part 65 for applying a load to the test piece 51, and the positions of the test piece 51 are moved back and forth and right and left. It has a pair of adjustment levers 63 for fine adjustment.
    [22] The process of measuring the interfacial bond strength of the specimen 51 using such a load application system 60 is as follows.
    [23] First, as shown in FIG. 6, the second region II of the specimen 51 may be cantilevered to the specimen fixing portion 61 so as to apply a load to the first region I of the specimen 51. Fix it. Then, finely adjust the position of the specimen 51 with the control lever 63 so that the load point spaced a certain distance from the specimen fixing portion 61 is located below the load application portion 65, and then the load application portion 65 ) Is applied to the first region (I).
    [24] When the load is applied in this way, as shown in FIG. 8, the displacement of the specimen 51 increases as the load increases, and the crack length between the substrate 53 and the thin film 55 increases rapidly. Looking at the change in the crack length with time, as shown in Figure 9, the crack length is instantaneously increased at the point where the pre-crack ends and crack growth begins. As shown in FIG. 8, when the crack length between the substrate 53 and the thin film 55 increases rapidly, the load tends to decrease rapidly. Because the crack grows in the opposite direction to the load point, the moment (force) applied to the crack point becomes larger as the crack grows. Since this can provide greater driving force to crack growth, the load applied tends to decrease.
    [25] However, when the interfacial bond strength is measured by this conventional method, it is difficult to grasp the correlation between the load and the crack length because the crack propagation occurs abruptly, and the value of the surface fracture energy evaluated due to the inertia and measurement sensitivity of the experimental equipment. There is a problem that is overestimated. In addition, since only the optical microscope is used to observe the crack, not only real time measurement is possible, but also there is a problem that it is impossible to measure the exact crack length by causing a considerable error. Accordingly, it is necessary to find a method to prevent the sudden crack propagation and to accurately measure the crack length.
    [26] Accordingly, it is an object of the present invention to provide an interfacial bond strength evaluation specimen and its interfacial bond strength evaluation method, which can facilitate and easily measure the interfacial bond strength.
    [27] It is also an object of the present invention to prevent the sudden crack propagation and to accurately measure the crack length, so that the interface bonding strength evaluation specimen and the interface bonding strength evaluation method that can easily and easily measure the interface bonding strength To provide.
    [1] 1 is a side view of the specimen form and the load application system fixed state according to the invention,
    [2] Figure 2 is a graph showing the relationship between the load and displacement when applying a load on the specimen of Figure 1,
    [3] 3 is a graph showing a change in crack length with time when a load is applied to the specimen of FIG.
    [4] Figure 4 is a graph showing the relationship between the moment and the crack length acting on the crack when applying the load to the specimen of Figure 1,
    [5] 5 is a graph showing the relationship between the interfacial junction energy and displacement obtained in accordance with the present invention,
    [6] 6 is a side view of a conventional load application system fixed state of the specimen;
    [7] 7 is a plan view of the load application system,
    [8] 8 is a graph showing a relationship between a load and a displacement when a load is applied to the specimen of FIG. 6,
    [9] 9 is a graph showing a change in crack length with time when a load is applied to the specimen of FIG.
    [10] FIG. 10 is a graph showing a relationship between a moment and a crack length when a load is applied to the specimen of FIG. 6.
    [11] * Explanation of symbols for the main parts of the drawings
    [12] 1 specimen 3: substrate
    [13] 5: thin film 7: adhesive
    [14] 9: reinforcement 60: load application system
    [15] 61: substrate fixing
    [28] The object is, according to the present invention, a first region consisting of only a substrate, which is fixed to a jig of a load application device; A second region formed by laminating a second material made of a different material from the substrate and a reinforcement made of the same material as the substrate, on one side of the substrate to which the load is applied by the load applying unit of the load applying apparatus. The interface bonding strength is achieved by the test specimen.
    [29] The second material of the second region is a thin film, and before the thin film is manufactured, a precrack formed by partially coating copper having low adhesion to the substrate to the substrate to reduce the adhesion between the substrate and the thin film. desirable.
    [30] On the other hand, the object is, according to another field of the present invention, the interface bonding of the specimen having a first region consisting of only the substrate and a second region formed by attaching a second material made of a different material to the substrate on one side of the substrate A strength evaluation method comprising: coupling a reinforcement made of the same material as the substrate to the second region; Fixing the first region of the specimen to an arbitrary jig; Applying a load to the second region of the specimen; Measuring a crack length between the substrate and the second material that occurs as the load is applied; A critical fracture energy, which is a critical energy at which a crack occurs between the substrate and the second material, is calculated by using the relationship between the load and the crack length. Can be.
    [31] Here, it is preferable to design the specimen so that the force applied at the point of occurrence of cracking between the substrate and the second material, that is, the driving force, becomes smaller when the load increases.
    [32] The second material of the second region is a thin film, and before the thin film is manufactured, a precrack formed by partially coating copper having low adhesion to the substrate to the substrate to reduce the adhesion between the substrate and the thin film. desirable.
    [33] The crack length at the critical load is preferably calculated by the following equation derived by applying the compliance method.
    [34]
    [35] Where E 1 , E 2 , E 3 , and E 4 are the modulus of elasticity of each material, L is the length of the specimen excluding the area fixed to the specimen fixing part, c is the crack length, and c is the first area minus c. Length.
    [36] The critical breakdown energy is preferably calculated by the following equation.
    [37]
    [38] here, ego, to be.
    [39] Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the present invention.
    [40] In general, when describing a phenomenon in which a force-induced material causes fracture, define and use the threshold of force applied at the moment of failure. This is because failure occurs only if the applied force exceeds its threshold. The simplest threshold to explain the failure phenomenon is the failure strength, which is the value of the force exerted by the failure divided by the cross-sectional area. On the other hand, the threshold is sometimes defined as an energy form, because when the force is applied, strain energy accumulates in the material, and when this energy becomes too large to cause the material to withstand breakdown. In this way, it is the critical fracture energy that corresponds to the critical energy at which destruction occurs. In order to reduce the experimental error and apply the threshold quantitatively, it is desirable to use the concept of fracture energy rather than fracture strength.
    [41] This concept of failure energy can be applied to the breakdown of the interface between two different materials, and the critical breakdown energy can be used as the threshold value at the breakdown of the interface. This critical breakdown energy is called interfacial bonding strength. Accordingly, the present interface bonding strength evaluation method evaluates the interface bonding strength by quantifying fracture energy at the time of specimen cracking.
    [42] The interfacial bond strength evaluation specimen (1, hereinafter referred to as 'test specimen') used in the evaluation method includes a substrate 3, a thin film 5, and a substrate to be evaluated for bonding strength, as shown in FIG. The reinforcing material 9 formed of the same material as (3) is provided by being laminated in sequence. At this time, the reinforcing material 9 may be attached to the thin film 5 using the adhesive 7 or the bonding material depending on the material, or may be attached to the thin film 5 by a method such as high temperature thermal diffusion or welding.
    [43] The specimen 1 is formed in a long bar shape to one side, the thin film 5 and the reinforcing material 9 is attached only to one region of the substrate 3 along the longitudinal direction of the specimen (1). Here, the region which consists only of the board | substrate 3 is called 1st area | region I, and the area | region where the thin film 5 and the reinforcing material 9 were attached to the board | substrate 3 is called 2nd area | region II.
    [44] The test piece 1 forms a precrack between the substrate 3 and the thin film 5 before the experiment, and there are various methods of forming the precrack according to the type of the thin film. For example, when the TiN thin film is bonded to a high speed steel substrate to prepare the specimen 1, the substrate 3 and the thin film (part 3) may be partially coated with copper having low adhesion to high speed steel before the thin film is manufactured. The precrack is formed by lowering the adhesion of 5). This precracking region is included in the first region (I).
    [45] The experiment for evaluating the interface bonding strength of the specimen (1) is to use a displacement control method, the displacement control method is to control the application of the load so that the displacement of the specimen (1) is constantly increased, the load at this time How to measure.
    [46] The process of evaluating interfacial bond strength using the displacement control method is as follows.
    [47] First, the specimen 1 is fixed to a load application system 60 capable of measuring the deformation of the specimen according to the load as shown in FIG. 7, and at this time, the first region I of the specimen 1 is It is fixed to the specimen fixing portion 61 of the inspection equipment (60). Then, the load application part 65 is lowered to the load point at the predetermined position of the second region II to apply the load. During the load application, the load application system 60 measures the displacement of the specimen 1 with the passage of time of the load and the crack length between the substrate 3 and the thin film 5.
    [48] The displacement of the specimen 1 according to the load measured by the load application system 60 is as shown in FIG. In a section where the load applied to the specimen 1 is less than or equal to a certain amount, the displacement of the specimen 1 increases in proportion to the load, and the displacement of the specimen 1 increases at a constant rate by the elastic force of the substrate 3. This section is called an elastic deformation region. After this elastic deformation region, the displacement increases with a steeper slope than the elastic deformation region as the load increases, and at this time, crack propagation between the substrate 3 and the thin film 5 starts. The critical point at which the crack propagation starts is called the critical load point, and the load at this time is called the critical load Pc.
    [49] On the other hand, when the crack length is measured over time after the crack propagation starts, as shown in FIG. 3, the crack length does not increase rapidly but increases at a constant rate as time passes. This is because the moment (force) applied to the point where the crack occurs as the crack grows in the load point direction becomes smaller as the crack length increases, as shown in FIG. 4. Therefore, even if the load increases, the crack does not grow rapidly and is made stable.
    [50] The process of calculating the fracture energy of the specimen 1 using the graphs of FIGS. 2 and 3 obtained through the experiment is as follows.
    [51] First, in order to obtain the total energy accumulated in the specimen 1 when the load P is applied to the specimen 1, the first region I and the second region II of the specimen 1 using classical beam bending theory. The energy in is given by
    [52] [Equation 1]
    [53]
    [54]
    [55] Here, ｈ 1 , ｈ 2 , ｈ 3 , ｈ 4 are the thickness of each of the reinforcement 9, the binder, the thin film 5, and the substrate constituting the test piece 1, respectively, where ｂ is the width of each material in the horizontal direction, E 1 , E 2 , E 3 , and E 4 are elastic moduli of each material. L is the length of the specimen 1 except for the region fixed to the specimen fixing portion 61, c is the crack length, and ｌ is the length obtained by subtracting c from the first region (I).
    [56] On the other hand, I4 and Ic in Equation 1 are expressed as follows.
    [57]
    [58]
    [59]
    [60] The critical breakdown energy is the total energy change according to the propagation per unit area of the crack, so using [Equation 1], the critical breakdown energy Ｇc can be calculated as follows.
    [61] [Equation 2]
    [62]
    [63] Accordingly, when the critical load Pc and the crack length are measured through the above experiment, the critical fracture energy can be obtained through Equation 1, and the obtained critical fracture energy can be used as a criterion of interfacial bonding strength. That is, as described above, when a load is applied, strain energy accumulates in the specimen 1, and when this energy becomes too large to be tolerated, fracture occurs. The value corresponds to the interface bonding strength of the interface to which the thin film 5 is bonded.
    [64] On the other hand, it is essential to measure the crack length in the interface bonding strength evaluation experiment, but measuring the crack length during the experiment is less accurate. Accordingly, if the compliance method is applied so that fracture energy can be obtained without directly measuring the crack length, the compliance S has the following relationship with the displacement δ and the load P.
    [65] ego,
    [66] Because of,
    [67]
    [68]
    [69] Therefore, crack length c is calculated | required as following [Equation 3].
    [70] [Equation 3]
    [71]
    [72] Substituting [Equation 3] into [Equation 2] for obtaining such a crack length, the critical fracture energy can be summarized as follows.
    [73] [Equation 4]
    [74]
    [75] here, ego, to be.
    [76] Therefore, by measuring the crack length at the critical load, the critical fracture energy can be obtained only by the information on the load and the displacement. When the fracture energy is calculated using the Equation 4 and compared with the crack length, as shown in FIG. 5, the fracture energy is constant during the crack.
    [77] Thus, in this evaluation method, the critical fracture energy of the interface can be obtained simply by knowing only the crack length and the critical load by taking the maximum value of the fracture energy according to the crack length as the critical fracture energy and using it as a quantitative index of the interface bonding strength. . In addition, since the critical fracture energy can be measured only by the crack length and the critical load, information on the mechanical properties of the thin film or the solder to be measured is not necessary. In addition, by deriving an equation for calculating the crack length at the interface between the substrate and the thin film using the relationship between the load and the displacement obtained by the experiment, the crack length can be known in real time during the propagation of the crack. Therefore, if only the critical load is obtained, the critical breakdown energy can be obtained. On the other hand, as shown in Figure 3, because the crack is made stable, the overestimation of the breakdown energy can be eliminated, it is possible to more accurately evaluate the interface bonding strength.
    [78] As described above, according to the present invention, it is possible to easily and accurately evaluate the interface bonding strength.
    [79] In addition, according to the present invention, it is possible to prevent the sudden crack propagation and to accurately measure the crack length, thereby making it easy and easy to measure the interfacial bonding strength.
    权利要求:
    Claims (5)
    [1" claim-type="Currently amended] A first region made of only a substrate, fixed to the jig of the load application device;
    A second region formed by laminating a second material made of a different material from the substrate and a reinforcement made of the same material as the substrate, on one side of the substrate to which the load is applied by the load applying unit of the load applying apparatus. Interfacial bond strength test specimen.
    [2" claim-type="Currently amended] The method of claim 1,
    The second material of the second region is a thin film,
    An interfacial bond strength evaluation test piece characterized in that a pre-crack is formed by partially coating copper having low adhesion to the substrate before the thin film is manufactured, thereby reducing the adhesion between the substrate and the thin film.
    [3" claim-type="Currently amended] In the interface bonding strength evaluation method of the test piece having a first region consisting of a substrate and a second region formed by attaching a second material made of a different material to the substrate on one side of the substrate,
    Coupling a reinforcement made of the same material as the substrate to the second region;
    Fixing the first region of the specimen to an arbitrary jig;
    Applying a load to the second region of the specimen;
    Measuring a crack length between the substrate and the second material that occurs as the load is applied;
    And calculating a critical fracture energy which is a critical energy at which cracking occurs between the substrate and the second material by using a relationship between the load and the crack length.
    [4" claim-type="Currently amended] The method according to claim 3 or 4,
    The method of evaluating interfacial bond strength of a specimen, wherein the crack length at the critical load is calculated by the following equation derived by applying a compliance method;

    Where E1, E2, E3, and E4 are the modulus of elasticity of each material, L is the length of the specimen excluding the area fixed to the specimen fixing part, c is the crack length, and c is the length minus c by the first area.
    [5" claim-type="Currently amended] The method of claim 5,
    The critical fracture energy is calculated by the following equation derived from the beam bending theory of the energy in the first region and the second region;

    here, ego, to be.
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    同族专利:
    公开号 | 公开日
    KR100404659B1|2003-11-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2001-05-10|Application filed by 권동일
    2001-05-10|Priority to KR10-2001-0025610A
    2002-11-18|Publication of KR20020086019A
    2003-11-07|Application granted
    2003-11-07|Publication of KR100404659B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR10-2001-0025610A|KR100404659B1|2001-05-10|2001-05-10|Specimen and test method of interfacial adhensive strength|
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