Measurement method and peeling method

Abstract

To easily peel a semiconductor chip from a substrate.SOLUTION: A measurement method according to one embodiment of the present invention, which measures joint strength, while peeling a semiconductor chip (3) jointed to a main surface (2a) of a substrate (2), using a blade (4) having a blade angle that is an acute angle (4b), includes steps of: preparing the semiconductor chip jointed to the main surface of the substrate, which has an outer peripheral end part (3a) chamfered on a curve surface (3b) protruding outward; inserting the blade along the main surface, toward the outer peripheral end part of the semiconductor chip, contacting an inclined surface (4a) of the blade with the curve surface of the outer peripheral end part of the semiconductor chip and peeling the semiconductor chip from the substrate by making force act, in a separating direction from the substrate, on the semiconductor chip; and measuring joint strength between the substrate and the semiconductor chip, on the basis of a length from a contact point where the blade contacts the semiconductor chip to a point where the semiconductor chip is peeled from the substrate.SELECTED DRAWING: Figure 6D

Description

[Technical field]

[0001] The present invention relates to a measurement method and a peeling method. [Background technology]

[0002] A method is known in which a blade is inserted into the bonding surface of two bonded substrates to peel the substrates and measure the bonding strength based on the peeled length. For example, Patent Document 1 discloses that the bonding strength of the substrates is evaluated by such a blade insertion method. Specifically, the bonding strength of the substrates can be evaluated from values ​​such as the length of the crack between the substrates caused by peeling the substrates, the thickness of the blade, and the thickness of each of the two substrates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4348454 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when using the blade insertion method with a single-edged blade to bond the bonding surfaces of two such substrates, there are cases where the substrates are difficult to peel apart, such as when the bond between the substrates is strong or when the substrates try to rebond even after being peeled apart.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a measuring method and a peeling method that enable a semiconductor chip to be easily peeled off from a substrate. [Means for solving the problem]

[0006] A measurement method according to one embodiment of the present invention is a measurement method for measuring bonding strength by peeling a semiconductor chip bonded to a main surface of a substrate using a blade having an acute blade angle, the method including: preparing a semiconductor chip bonded to a main surface of a substrate, the semiconductor chip having an outer peripheral edge that is chamfered into a curved surface that convex outward; inserting a blade having a blade angle that is a first acute angle along the main surface toward the outer peripheral edge of the semiconductor chip, bringing the inclined surface of the blade into contact with the curved surface of the outer peripheral edge of the semiconductor chip, and applying a force to the semiconductor chip in a direction away from the substrate, thereby peeling the semiconductor chip from the substrate; and measuring the bonding strength between the substrate and the semiconductor chip based on the length from the point of contact where the blade contacts the semiconductor chip to the point where the semiconductor chip and the substrate are peeled off.

[0007] According to this aspect, a blade is inserted along the main surface of a semiconductor chip bonded to a substrate toward the outer peripheral edge of the curved surface of the semiconductor chip that is chamfered, and the inclined surface of the blade is brought into contact with the curved surface of the outer peripheral edge of the semiconductor chip to perform peeling. At this time, the inclined surface of the blade and the curved surface of the semiconductor chip are in line contact in the width direction, so that the contact area can be reduced. As a result, friction between the inclined surface of the blade and the curved surface of the semiconductor chip is reduced, and the semiconductor chip can be easily peeled off from the substrate. Therefore, the bonding strength between the two can be easily measured. Effect of the Invention

[0008] According to the present invention, it is possible to provide a measuring method and a peeling method that enable a semiconductor chip to be easily peeled off from a substrate. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an example of a semiconductor module to which the measurement method according to the first embodiment can be applied. [Diagram 2] FIG. 2 is a block diagram showing an example of a bonding strength measuring device used in the measuring method according to the first embodiment. [Diagram 3] FIG. 2 is a perspective view showing an example of a blade used in the measurement method according to the first embodiment. [Figure 4] 4 is a flowchart showing a measurement method according to the first embodiment. [Diagram 5] FIG. 4 is a diagram showing an example when the measurement method according to the first embodiment is performed. [Figure 6A] 4A to 4C are cross-sectional views showing an example of a measuring method according to the first embodiment in progress. [Figure 6B] 4A to 4C are cross-sectional views showing an example of a measuring method according to the first embodiment in progress. [Figure 6C] 4A to 4C are cross-sectional views showing an example of a measuring method according to the first embodiment in progress. [Figure 6D] 4A to 4C are cross-sectional views showing an example of a measuring method according to the first embodiment in progress. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings of the present embodiment are merely examples, and the dimensions and shapes of each part are schematic, and the technical scope of the present invention should not be interpreted as being limited to the embodiment.

[0011] First Embodiment 1, for the purpose of explaining the relative directional relationships, the right direction on the paper will be called the X-axis positive direction, the back direction on the paper will be called the Y-axis positive direction, and the top direction on the paper will be called the Z-axis positive direction. The left direction on the paper will be called the X-axis negative direction, the front direction on the paper will be called the Y-axis negative direction, and the bottom direction on the paper will be called the Z-axis negative direction.

[0012] FIG. 1 is a cross-sectional view showing an example of a semiconductor module to which the measurement method according to the first embodiment of the present invention can be applied. The semiconductor module 1 includes a semiconductor wafer 2 and a semiconductor chip 3. An outer peripheral end 3a of the semiconductor chip 3 is chamfered to form a curved surface 3b. The curved surface 3b is chamfered to form a convex portion toward the outside of the semiconductor chip 3 (positive and negative directions of the X-axis). The back surface 3c of the semiconductor chip 3 may be joined to the main surface 2a of the semiconductor wafer 2 by electrostatic force. In the following description, the semiconductor wafer 2 is taken as an example of a substrate to which the measurement method according to the first embodiment of the present invention can be applied, but the substrate may be made of various metals, alloys, glass, ceramics, resin, or other materials.

[0013] <Peel strength measuring device used in the measuring method according to the first embodiment> Fig. 2 is a diagram showing an example of a peel strength measuring device used in the measurement method according to the first embodiment. The peel strength measuring device according to the first embodiment includes a blade 4 for peeling a semiconductor chip 3 from a semiconductor wafer 2, and a measuring unit 5 for measuring the bonding strength between the semiconductor wafer 2 and the semiconductor chip 3. Steps S1 to S4 shown in Fig. 4, which will be described later, are examples performed using the peel strength measuring device according to the first embodiment. The measuring unit 5 may be, for example, a measuring device including an edge sensor, a surface potential measuring sensor, etc.

[0014] 3 is a perspective view showing an example of a blade used in the measurement method according to the first embodiment of the present invention. The blade 4 has an inclined surface 4a with respect to the bottom surface. The blade 4 may be fixed to a fixing member (not shown) before use. With this configuration, it is possible to prevent the blade 4 from buckling. The inclined surface 4a is a flat surface.

[0015] Fig. 4 is a flowchart showing the measurement method according to the first embodiment of the present invention. The measurement method according to the first embodiment of the present invention proceeds along steps S1 to S4. The flowchart will be described below with reference to Fig. 5 and Figs. 6A to 6D as appropriate.

[0016] 5 is a diagram showing an example of carrying out the measurement method according to the first embodiment of the present invention. A blade 4 is inserted into a semiconductor module 1 in an insertion direction (positive direction of the X-axis). The length of the blade 4 in the width direction (positive direction of the Y-axis) may be greater than the length of the outer peripheral end 3a chamfered on the curved surface 3b of the semiconductor chip 3 in the width direction (positive direction of the Y-axis). With this configuration, the contact area is small and peeling is performed by making line contact over the entire surface with respect to the width direction (positive direction of the Y-axis) of the curved surface 3b of the semiconductor chip 3, so that peeling can be performed with little friction.

[0017] 6A is a cross-sectional view showing an example of the measurement method according to the first embodiment in progress. A blade 4 is inserted toward the outer peripheral end 3a that is chamfered on the curved surface 3b of the semiconductor chip 3. That is, the inclined surface 4a of the blade 4, which has an acute cutting angle 4b, is inserted in the positive direction of the X-axis along the main surface 2a toward the gap 3d between the curved surface 3b and the main surface 2a.

[0018] The blade 4 may have an acute angle 4b of, for example, 45° or less. Furthermore, a blade having an angle of 10° to 20° may be used. By setting the blade angle to 45° or less, the blade 4 can more easily enter between the semiconductor chip 3 and the semiconductor wafer 2, and the contact point between the inclined surface 4a of the blade 4 and the curved surface 3b of the semiconductor chip 3 is located on the curved surface 3b near the bonding surface between the semiconductor wafer 2 and the semiconductor chip 3, so that a force can be more easily applied to the semiconductor chip 3 in a direction away from the semiconductor wafer 2. The combination of the angle of the blade 4 and the curvature of the curved surface 3b shown in FIG. 6A is an example, and other combinations may be used.

[0019] 6B is a cross-sectional view showing an example of the measurement method according to the first embodiment in progress. The blade 4 is inserted into the outer peripheral end 3a, and the inclined surface 4a of the blade 4 comes into contact with the curved surface 3b of the semiconductor chip 3 at the contact point CP1, and makes line contact along the positive direction of the Y axis. At this time, a peeling force PF1 acts in a direction perpendicular to the inclined surface 4a of the blade 4 (a direction between the positive directions of the X axis and the positive directions of the Z axis), peeling the semiconductor chip 3 from the main surface 2a of the semiconductor wafer 2.

[0020] In step S1, the blade 4 is brought into contact with the inclined surface 4a of the blade 4 and the curved surface 3b of the outer peripheral end 3a of the semiconductor chip 3, as shown in FIG.

[0021] Step S2 is to peel off the semiconductor chip 3. The blade 4 is advanced in the positive direction of the X-axis in the order of Fig. 6B, Fig. 6C, and Fig. 6D, whereby the semiconductor chip 3 is gradually peeled off from the main surface 2a of the semiconductor wafer 2.

[0022] 6C is a cross-sectional view showing an example of the measurement method according to the first embodiment in progress. The inclined surface 4a of the blade 4 comes into contact with the curved surface 3b of the semiconductor chip 3 at the contact point CP2, and makes line contact along the positive direction of the Y-axis. At this time, a peeling force PF2 acts in a direction perpendicular to the inclined surface 4a of the blade 4 (a direction between the positive directions of the X-axis and the positive directions of the Z-axis), peeling the semiconductor chip 3 from the main surface 2a of the semiconductor wafer 2.

[0023] 6D is a cross-sectional view showing an example of the measurement method according to the first embodiment in progress. The inclined surface 4a of the blade 4 comes into contact with the back surface 3c of the semiconductor chip 3 at the contact point CP3, and makes line contact along the positive direction of the Y-axis. At this time, a peeling force PF3 acts in a direction perpendicular to the inclined surface 4a of the blade 4 (a direction between the positive directions of the X-axis and the positive directions of the Z-axis), peeling the semiconductor chip 3 from the main surface 2a of the semiconductor wafer 2. Thereafter, the blade 4 is advanced in the positive direction of the X-axis, so that the semiconductor chip 3 is gradually peeled off from the main surface 2a of the semiconductor wafer 2.

[0024] In step S3, the peeling length is measured. In Fig. 6D, for example, the length is measured from the contact point CP3 between the upper end of the inclined surface 4a of the blade 4 and the back surface 3c of the semiconductor chip 3 to the point where the semiconductor chip 3 and the semiconductor wafer 2 are peeled off.

[0025] In step S4, the bonding strength is measured. The bonding strength is measured, for example, by calculating the bonding strength using the thickness of the blade 4 and the thickness of the semiconductor chip 3 obtained in advance, and the peeling length measured in step S3. The bonding strength may be measured, for example, by a measuring unit 5 including an edge sensor, a surface potential measuring sensor, etc. (not shown).

[0026] The bonding strength between the semiconductor chip 3 and the semiconductor wafer 2 can be evaluated using the bond energy of the bonding surface. The bond energy can be calculated by the following formula.

number

[0027] According to the above embodiment, by chamfering the outer peripheral end 3a of the semiconductor chip 3 to form the curved surface 3b and setting the blade 4 to the inclined surface 4a, the contact area between the blade 4 and the semiconductor chip 3 is reduced, which reduces the frictional force and facilitates penetration. By using such a blade 4, the semiconductor chip 3 chamfered to the curved surface 3b can be easily peeled off from the semiconductor wafer 2.

[0028] The measuring method according to the first embodiment of the present invention has been described above. The peeling method according to the embodiment of the present invention will be described with reference to Figs. 1 to 6D, which are related to the measuring method according to the first embodiment.

[0029] <An example of a peeling method according to an embodiment of the present invention> An example of the peeling method according to the embodiment of the present invention may be performed using the semiconductor module 1, the measuring unit 5, and the blade 4 shown in Figures 1, 2, and 3. In the example of the peeling method according to the embodiment of the present invention, steps S1 and S2 shown in Figure 4 are performed in this order, similar to the measurement method according to the first embodiment. In the example of the peeling method according to the embodiment of the present invention, the blade 4 shown in Figure 6D may be advanced in the positive direction of the X-axis to completely peel off the semiconductor chip 3 from the main surface 2a of the semiconductor wafer 2.

[0030] The first embodiment described above is intended to facilitate understanding of the present invention, and is not intended to limit the present invention. The present invention may be modified / improved without departing from the spirit thereof, and the present invention also includes equivalents thereof. That is, a design change made by a person skilled in the art to the first embodiment is also included in the scope of the present invention as long as it has the characteristics of the present invention. For example, the elements of the first embodiment and their arrangement, materials, conditions, shapes, sizes, etc. are not limited to those exemplified, and can be changed as appropriate. In addition, the elements of the first embodiment can be combined to the extent technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the characteristics of the present invention.

[0031] (Appendix 1) The measurement method according to this embodiment is a measurement method that uses a blade having an acute blade angle to peel off a semiconductor chip bonded to a main surface of a substrate and measure its bonding strength, and includes: preparing a semiconductor chip bonded to a main surface of a substrate, the semiconductor chip having an outer peripheral end that is chamfered into a curved surface that convex outward; inserting a blade having a blade angle that is a first acute angle along the main surface toward the outer peripheral end of the semiconductor chip, bringing the inclined surface of the blade into contact with the curved surface of the outer peripheral end of the semiconductor chip, and applying a force to the semiconductor chip in a direction away from the substrate, thereby peeling the semiconductor chip from the substrate; and measuring the bonding strength between the substrate and the semiconductor chip based on the length from the point of contact where the blade contacts the semiconductor chip to the point where the semiconductor chip and the substrate are peeled off.

[0032] (Appendix 2) In the measurement method described in Supplementary Note 1 above, the first acute angle of the blade is less than 45° and greater than or equal to 10°.

[0033] (Appendix 3) In the measurement method described in Supplementary Note 1 or Supplementary Note 2, the length of the inclined surface of the blade in the width direction is greater than the length of the curved surface of the semiconductor chip in the width direction.

[0034] (Appendix 4) In the measuring method according to any one of Supplementary Note 1 to Supplementary Note 3, the substrate is a semiconductor wafer.

[0035] (Appendix 5) In the measuring method according to any one of Supplementary Note 1 to Supplementary Note 4, the measuring method includes peeling off the semiconductor chip that has been electrostatically bonded to the main surface of the substrate.

[0036] (Appendix 6) The peeling method according to this embodiment is a peeling method that includes the steps of preparing a semiconductor chip bonded to a main surface of a substrate, the semiconductor chip having an outer peripheral edge that is chamfered into a curved surface that convex outwardly, and inserting a blade having an acute cutting edge angle along the main surface toward the outer peripheral edge of the semiconductor chip, bringing the inclined surface of the blade into contact with the curved surface of the outer peripheral edge of the semiconductor chip, and applying a force to the semiconductor chip in a direction away from the substrate, thereby peeling the semiconductor chip from the substrate. [Explanation of symbols]

[0037] 1. Semiconductor module 2...Semiconductor wafer 2a…main surface 3. Semiconductor chips 3a...Outer edge 3b…Curved surface 3c…Back side 3d…Gap 4…Blade 4a…Slope surface 4b...Acute angle 5...Measuring part CP1~CP3…Contact points PF1~PF3...Peeling force

Claims

1. A method for measuring bonding strength by peeling a semiconductor chip bonded to a main surface of a substrate using a blade having an acute cutting edge, comprising the steps of: preparing a semiconductor chip bonded to a main surface of a substrate, the semiconductor chip having an outer peripheral edge that is chamfered into a curved surface that forms an outwardly protruding portion; inserting the blade along the main surface toward the outer peripheral end of the semiconductor chip, bringing an inclined surface of the blade into contact with the curved surface of the outer peripheral end of the semiconductor chip, and applying a force to the semiconductor chip in a direction away from the substrate, thereby peeling the semiconductor chip from the substrate; measuring a bonding strength between the substrate and the semiconductor chip based on a length from a contact point where the blade contacts the semiconductor chip to a point where the semiconductor chip is peeled off from the substrate. Measurement method.

2. The method of claim 1 , wherein the first acute angle of the blade is less than 45° and greater than 10°.

3. The measurement method according to claim 1 , wherein a length in a width direction of the inclined surface of the blade is greater than a length in a width direction of the curved surface of the semiconductor chip.

4. The measuring method according to claim 1 , wherein the substrate is a semiconductor wafer.

5. The measuring method according to claim 1 , wherein the peeling method includes peeling off the semiconductor chip that is electrostatically bonded to the main surface of the substrate.

6. A peeling method comprising the steps of: preparing a semiconductor chip bonded to a main surface of a substrate, the semiconductor chip having an outer peripheral edge that is chamfered into a curved surface that forms an outwardly protruding portion; a blade having an acute cutting edge is inserted along the main surface toward the outer peripheral end of the semiconductor chip, and an inclined surface of the blade is brought into contact with the curved surface of the outer peripheral end of the semiconductor chip, and a force is applied to the semiconductor chip in a direction away from the substrate, thereby peeling the semiconductor chip from the substrate; The peeling method includes the steps of:

Images