Bonding apparatus and bonding method

Abstract

The present application provides a bonding apparatus comprising: a jig configured to support a periphery of a substrate, where the substrate has a semiconductor die mounted thereon; a top cover operably attached to the clamp and configured to cover the substrate and the semiconductor die, where the top cover comprises: a clamping element operably attached to the clamp and configured to cover a portion of the substrate to reduce warpage of the substrate, where the clamping element comprises an opening, and the clamping element is configured to cover a portion of the substrate to reduce warpage of the substrate; the opening is configured to accommodate and expose the semiconductor bare chip; and a light transmissive element mounted within the opening and configured to cover the semiconductor die to reduce warpage of the semiconductor die and allow a laser beam to pass through the light transmissive element to the semiconductor die when the top cover is attached to the jig; and a laser source configured to emit a laser beam, the laser beam passing through the light transmissive element.

Description

Technical Field

[0001] This application generally relates to semiconductor technology, and more specifically, to bonding apparatus and bonding methods. Background Technology

[0002] In the semiconductor industry, laser-assisted bonding (LAB) technology is widely used in chip assembly processes. During the LAB process, a laser source emits a laser beam to reflow the solder bumps between the substrate and the semiconductor die, so that the reflowed solder bumps bond the semiconductor die to the substrate. Typically, during the bonding process, a large amount of heat is directly radiated to the semiconductor die and the substrate, which can cause warpage problems and may adversely affect the performance of the manufactured devices.

[0003] Therefore, there is a need for a bonding device that can bond semiconductor dies to a substrate and reduce warpage. Summary of the Invention

[0004] The objective of this application is to provide a bonding apparatus for bonding semiconductor dies to a substrate and reducing warpage.

[0005] According to one aspect of this application, a bonding device is provided. The bonding apparatus includes: a clamp configured to support the periphery of a substrate having a semiconductor die mounted thereon; a top cover operably attached to the clamp and configured to cover the substrate and the semiconductor die when attached to the clamp, wherein the top cover includes: a clamping element operably attached to the clamp and configured to cover a portion of the substrate to reduce warpage when the top cover is attached to the clamp, wherein the clamping element includes an opening at the center of the clamping element and the opening is configured to receive and expose the semiconductor die; a light-transmitting element mounted within the opening and configured to cover the semiconductor die when the top cover is attached to the clamp to reduce warpage of the semiconductor die and allow a laser beam to pass through the light-transmitting element to reach the semiconductor die; and a laser source configured to emit a laser beam that passes through the light-transmitting element to reach the semiconductor die.

[0006] According to another aspect of this application, a bonding method is provided, wherein the bonding method is performed by a bonding apparatus, the bonding apparatus comprising: a clamp; a top cover above the clamp, wherein the top cover includes a clamping element having an opening and a light-transmitting element disposed within the opening; and a laser source, and wherein the method comprises: placing a substrate between the top cover and the clamp, the substrate having a semiconductor die mounted thereon, wherein the clamp supports a periphery of the substrate and the top cover is attached to the clamp, wherein the clamping element covers a portion of the substrate and the light-transmitting element covers the semiconductor die; and emitting a laser beam through the light-transmitting element from the laser source toward the semiconductor die to bond the semiconductor die to the substrate via solder bumps, wherein the clamping element presses a portion of the substrate toward the clamp to reduce warpage of the substrate, and the light-transmitting element presses the semiconductor die toward the substrate to reduce warpage of the semiconductor die.

[0007] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and do not limit the invention. Furthermore, the accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with this specification, serve to explain the principles of the invention. Attached Figure Description

[0008] The accompanying drawings referenced herein form part of this specification. Unless the detailed description clearly indicates otherwise, the features shown in the drawings illustrate only some embodiments of this application, and not all embodiments of this application, and readers of this specification should not infer the contrary.

[0009] Figure 1A A side view of a bonding apparatus during the bonding step according to a first embodiment of this application is shown.

[0010] Figure 1B exhibit Figure 1A The top view of the clamp of the bonding device shown.

[0011] Figure 1C exhibit Figure 1A The top view of the top cover of the bonding device shown.

[0012] Figures 2A to 2C The various steps of a bonding method implemented by a bonding device according to a second embodiment of this application are illustrated.

[0013] Throughout the accompanying drawings, the same reference numerals will be used to refer to the same or similar parts. Detailed Implementation

[0014] The following detailed description of exemplary embodiments of this application takes into account the accompanying drawings, which form a part of the description. The drawings illustrate specific exemplary embodiments in which this application may be practiced. The detailed description, including the drawings, describes these embodiments in sufficient detail to enable those skilled in the art to practice this application. Those skilled in the art may further utilize other embodiments of this application and make logical, mechanical, and other changes without departing from the spirit or scope of this application. Therefore, the reader of the following detailed description should not interpret the description in a limiting sense, and the scope of the embodiments of this application is defined only by the appended claims.

[0015] In this application, unless otherwise expressly stated, the use of the singular includes the plural form. In this application, unless otherwise stated, the use of “or” means “and / or”. Furthermore, the use of the term “comprising” is not restrictive. Additionally, unless otherwise expressly stated, terms such as “element” or “assembly” cover both elements and assemblies comprising one unit and elements and assemblies comprising more than one sub-unit. Furthermore, the section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0016] As used herein, for ease of description, spatial relative terms such as “below,” “under,” “above,” “upper,” “upper,” “lower,” “left,” “right,” “vertical,” “horizontal,” and “side” may be used to describe the relationship between an element or feature and another element (or feature) or feature (or feature), as shown in the diagrams. In addition to the orientations depicted in the diagrams, the spatial relative terms are intended to cover different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein shall be interpreted accordingly. It should be understood that when an element is referred to as “connected to” or “coupled to” another element, the element may be directly connected to or coupled to the other element, or there may be intermediate elements present.

[0017] As mentioned above, in some chip assembly processes, laser-assisted bonding (LAB) technology uses LAB bonding equipment to bond semiconductor dies to packages. During the LAB process performed by the LAB bonding equipment, the fixtures of the LAB bonding equipment support the periphery of the substrate, and the top cover of the LAB bonding equipment can be further attached to the fixtures to cover a portion of the substrate. The laser source of the LAB bonding equipment then emits a laser beam to re-solder the solder bumps between the substrate and the semiconductor die, thereby bonding the semiconductor die to the substrate via the re-solder bumps. During the bonding process, a significant amount of heat is radiated directly from the laser source to the semiconductor die and the substrate and absorbed by them, while the fixtures and top cover, as a combination, apply force to the substrate to reduce warpage problems that may be caused by heat radiation. However, the inventors of this application have noted that the top cover of existing LAB bonding equipment has an opening at its center for receiving the semiconductor die and exposing it to the laser source, where no force can be applied, and therefore the warpage problem may still exist and remain unresolved.

[0018] To address the aforementioned problems, in some embodiments, a novel bonding apparatus is provided. This novel bonding apparatus utilizes a light-transmitting element to press a semiconductor die and substrate against the clamps of the bonding apparatus, while simultaneously allowing a laser beam to pass through the light-transmitting element to reach the semiconductor die. In this way, sufficient thermal radiation can reach the solder bumps between the semiconductor die and the substrate, and at the same time, warpage of the semiconductor die and substrate can be further reduced or even substantially avoided.

[0019] Figures 1A to 1C A bonding apparatus according to a first embodiment of this application is shown during a bonding step. Specifically, Figure 1A Showing a side view of the bonding device. Figure 1B exhibit Figure 1A The top view of the clamp of the bonding device shown, and Figure 1C exhibit Figure 1A The top view of the top cover 120 of the bonding device shown.

[0020] like Figure 1AAs shown, a bonding apparatus is provided for bonding a semiconductor die 101 to a substrate 100, such as a printed circuit board, during a bonding process (e.g., during a laser-assisted bonding (LAB) process). The semiconductor die 101 may be mounted at the center of the substrate 100, and solder paste (not shown) is formed between the substrate 100 and the semiconductor die 101 to electrically and mechanically connect the two. In some embodiments, the semiconductor die 101 may comprise a flip chip. Preferably, the semiconductor die 101 may comprise a system-on-a-chip (SOC) chip with a large size. Multiple sets of conductive pads may be formed on the top surface of the substrate 100 for mounting the semiconductor die 101 onto the substrate 100. In some embodiments, additional conductive pads may be formed on the bottom surface of the semiconductor die 101, which also facilitates mounting the substrate 100 onto the semiconductor die 101 via solder paste. The bonding apparatus also includes a laser source 140 disposed above the substrate 100 and the semiconductor die 101. Laser source 140 can emit a laser beam toward substrate 100 and semiconductor die 101, wherein the laser energy can be absorbed and converted into heat. For illustrative purposes, in Figure 1A In the process, the bonding equipment performs a bonding step, during which the semiconductor die 101 is bonded to the substrate 100, and the solder paste between the semiconductor die 101 and the substrate 100 can be heated and reflowed to form solder bumps, thereby forming a sufficient bond between the semiconductor die 101 and the substrate 100.

[0021] The bonding apparatus includes a fixture 110, with a channel passing through the center of the fixture 110. During the bonding step, a substrate 100 and a semiconductor die 101 disposed thereon can be placed on the fixture 110 and supported by the fixture 110 at the periphery of the substrate 100. Figure 1AIn the illustrated embodiment, the bonding apparatus further includes a bonding platform having a bottom cover 132 and a support block 130 attached to the bottom cover 132. During the bonding step, the support block 130 may be accommodated within a channel of a clamp 110 to support the substrate 100 together with the clamp 110. In some embodiments, the height of the support block 130 may be approximately the same as the height of the clamp 110, such that the bottom cover 132 may be attached to the bottom surface of the clamp 110 when the support block 130 supports the substrate 100. The bottom cover 132 provides additional mechanical support to support the clamp 110 and the components thereon. Furthermore, the support block 130 may have venting channels that can be distributed throughout the support block 130. The venting channels are fluidly coupled to a vacuum source 131 to apply a vacuum pressure during the bonding step to grip and support the substrate 100. In some embodiments, the venting channels may include a plurality of holes distributed throughout the support block 130 to provide a uniform vacuum pressure. In some other embodiments, the venting channels may include interconnecting channels or conduits therebetween. The vacuum pressure applied by the support block 130 can reduce the stress on the substrate 100, thereby improving potential warping problems.

[0022] Combination Figure 1B refer to Figure 1A The clamp 110 may have a rectangular layout, which may resemble the shape of the substrate 100. In some other embodiments, the clamp 110 may have other shaped layouts, such as circular, hexagonal, or octagonal, as long as the substrate 100 can be properly supported on the clamp 110. Furthermore, at least one magnet 111 is embedded within the clamp 110. In some embodiments, the magnet 111 may comprise at least one of the following materials: iron, nickel, and cobalt and their alloys, some alloys of rare earth metals, and some naturally occurring minerals, such as magnetite. Preferably, the magnet 111 may comprise SmCo. Furthermore, the magnets 111 are preferably evenly distributed within the clamp 110, for example, at or near the four edges of the clamp 110. Figure 1B In the illustrated embodiment, two magnets 111 are arranged at each of the four edges of the clamp 110. The magnets 111 may extend within the clamp 110 up to its thickness, i.e., both the top and bottom surfaces of the magnets 111 may be exposed from the clamp 110, allowing them to be placed closer to the top cover 120 when placed on the clamp 110. In some other embodiments, only the top surface of the magnets 110 may be exposed from the clamp 110. It is also understood that the magnets 111 may be embedded within the clamp 110, with their top surfaces not exposed from the clamp 110 but close enough to the top cover 120 to achieve a suitable magnetic field that attracts the clamp 110 and the top cover 120 (e.g., made of stainless steel) closer to each other. In some other embodiments, the magnets 111 may be formed as a single piece, such as a ring surrounding a channel, or as an array of magnets 111 uniformly distributed throughout the clamp 110 to provide a stronger magnetic field.

[0023] In addition, such as Figure 1B As shown, the clamp 110 may also include one or more support pins 113 on the front surface of the clamp 110. The support pins 113 can be used to secure the clamp 110 to the top cover 120, which will be described later.

[0024] Still referencing Figure 1A The bonding apparatus also includes a top cover 120. During the bonding step, the top cover 120 covers both the substrate 100 and the semiconductor die 101 to reduce potential warping issues of the substrate 100 and the semiconductor die 101. More specifically, the top cover 120 includes a clamping element 121 attached to a jig 110, the clamping element covering a portion of the periphery of the substrate 100. In some embodiments, the peripheral portion of the clamping element 121 extends downward to surround a lateral surface of the substrate 100, so that the substrate 100 can be securely clamped between the clamping element 121 and the jig 110 to avoid unwanted displacement during the bonding step. Figure 1C As shown, the clamping element 121 may have a shape and layout similar to the clamp 110 to mate with it. As mentioned above, the clamping element 121 comprises carbon steel, stainless steel, or other similar ferromagnetic materials that can be attracted by magnets embedded within the clamp 110 when the top cover 120 is attached to the clamp 110. Furthermore, the clamping element 121 may include one or more slots through the top cover 120 that mate in shape and position with one or more support pins on the clamp 110 to receive the corresponding support pins. Thus, the clamping element 121 can be securely fixed to the top surface of the clamp 110 without displacement. In other words, the clamping element 121 and the clamp 110 can be joined as a single unit, with a portion of the clamping element 121 fixed at a certain height to cover a portion of the substrate 100. When the substrate 100 is heated during the bonding step, the substrate 100 can be bent toward the clamping element 121 and thus apply force to the clamping element 121. Because the clamping element 121 is stationary and fixed in place, the portion of the substrate 100 covered by the clamping element 121 can press the substrate 100 against the clamp 110 in response to the force applied to the substrate 100, which reduces warping of the substrate 100. In some embodiments, a small gap may exist between the clamping element 121 and the top and / or side surfaces of the substrate 100 before heating the substrate 100 to allow for slight expansion of the substrate 100 during the bonding step. It is also understood that the clamping element 121 may be in direct contact with the substrate 100 to provide greater pressure to the substrate 100.

[0025] Furthermore, the clamping element 121 has an opening at its center, which accommodates and exposes the entire semiconductor die 101 when it is mounted on and protrudes from the substrate 100. The top cover 120 also includes a light-transmitting element 122 having dimensions and shape that match the size and shape of the opening, allowing the light-transmitting element 122 to be accommodated within the opening and cover the semiconductor die 101. In some embodiments, the light-transmitting element 122 may be fixed to the inner wall of the opening as part of the top cover 120, while the clamping element 121 serves as another part of the top cover 120. In this way, the substrate 100 and the semiconductor die 101 can be securely clamped between the top cover 120 and the clamp 110. More specifically, during the bonding step, the light-transmitting element 122 allows a laser beam to pass through it to reach the semiconductor die 101. Therefore, the heat radiated to the semiconductor die 101 is still sufficient to heat the semiconductor die 101 and the solder paste between the semiconductor and the substrate 100 to form solder bumps and thus bond the semiconductor die 101 to the substrate 100. In some embodiments, the laser beam emitted by the laser source 140 may be infrared radiation with a wavelength in the range of 900 nm to 1000 nm. Preferably, the wavelength may be 980 nm. The light-transmitting element 122 may comprise fused silica, CaF2, MgF2, crystalline silica, or ZnSe, which allow the transmission of laser radiation with a specific wavelength. In some other embodiments, the wavelength of the laser radiation may be varied depending on the laser source 140 used in the bonding step. Therefore, the material of the light-transmitting element 122 may be varied depending on the laser radiation used.

[0026] Still referencing Figure 1A The light-transmitting element 122 is fixed within the opening of the clamping element 121. Because the clamping element 121 is attracted by the magnet 111 within the clamp 110, the light-transmitting element 122 is firmly supported and fixed in place by the clamping element 121, at a certain distance from the semiconductor die 101. In some embodiments, the size of the light-transmitting element 122 is larger than the size of the semiconductor die 101, and when the top cover 120 is attached to the clamp 110, the light-transmitting element covers the entire semiconductor die 101. It is also understood that the size of the light-transmitting element 122 may be equal to or smaller than the size of the semiconductor die 101.

[0027] During the bonding step, when the laser beam passes through the light-transmitting element 122 to reach the semiconductor die 101 and heat it, the semiconductor die 101 bends towards the light-transmitting element 122 and thus applies force to it. Similar to the clamping element 121, the light-transmitting element 122 covering the semiconductor die 101 can press the semiconductor die 101 against the substrate 100 in response to the force applied to the semiconductor die 101, which reduces warpage of the semiconductor die 101. In this way, the light-transmitting element 122 not only ensures sufficient heat reaches the semiconductor die 101 but also reduces warpage of the semiconductor die 101. Furthermore, the light-transmitting element 122 prevents external contaminants from reaching and adhering to the semiconductor die 101 and the substrate 100, which reduces defects in the manufactured device and improves the bonding performance of the device.

[0028] In some embodiments, the height of the light-transmitting element 122 determines the total height of the device produced after the bonding step. In some embodiments, the light-transmitting element 122 may be in direct contact with the semiconductor die 101 to provide greater pressure to the semiconductor die 101 and maintain the height of the solder bumps at a controlled value. The distance between the bottom surface of the light-transmitting element 122 and the top surface of the semiconductor die 101 should be designed with the total height of the substrate 100, the semiconductor die 101, and the solder bumps to be formed after the bonding step in mind. In some other embodiments, slight warping or expansion of the semiconductor die 101 and the substrate 100 may be permitted. In this case, a small gap may exist between the light-transmitting element 122 and the top surface of the semiconductor die 101 before heating the semiconductor die 101. When determining the distance between the bottom surface of the light-transmitting element 122 and the top surface of the semiconductor die 101, the design can take into account the total height of the substrate 100, the semiconductor die 101, the solder bumps to be formed, and the permissible warpage of the semiconductor die 101 and the substrate 100 during the bonding step. In this way, the light-transmitting element 122 also acts as a constraint on controlling the height of the solder bumps and / or the warpage of the semiconductor die 101 and the substrate 100.

[0029] In some embodiments, the bottom surface of the light-transmitting element 122 may be positioned relative to the top surface of the semiconductor die 101 to meet various requirements of the bonding steps. For example, a plurality of microslots may be formed on the lateral surface of the inner wall of an opening within the holding element 121, these microslots being arranged at different heights. The light-transmitting element 122 may include at least one protrusion extending outward from the lateral surface of the light-transmitting element 122. Each of the at least one protrusion may be received by one of the microslots to hold the light-transmitting element 122 at a desired distance from the semiconductor die 101. For different bonding steps, the protrusion of the light-transmitting element 122 may be moved into different slots to adjust the distance between the bottom surface of the light-transmitting element 122 and the top surface of the semiconductor die 101.

[0030] In some embodiments, the light-transmitting element 122 may have a uniform thickness. In some other embodiments, the thickness of the region of the light-transmitting element 122 aligned with the solder paste may be less than the thickness of other regions of the light-transmitting element 122, so as to allow more laser radiation to pass through to heat the semiconductor die 101 and the underlying solder paste. It is also understood that the light-transmitting element 122 may include openings aligned with the solder paste. Therefore, the light-transmitting element 122 can ensure sufficient heat radiation to reflow the solder paste and form solder bumps, while simultaneously reducing warpage of the semiconductor die 101 and the substrate 100 during the bonding steps.

[0031] Therefore, in use Figures 1A to 1C During the bonding process shown in the diagram, where a semiconductor die 101 is bonded to a substrate 100, warpage of the semiconductor die 101 and the substrate 100 can be reduced by attaching a top cover 120, which has a clamping element 121 and a light-transmitting element 122, to a jig 110. Since the top cover 120 is firmly held by the jig 110 without displacement during the bonding step, the top cover 120 can press the semiconductor die 101 and the substrate 100 against the jig 110 without requiring a separate pressurization process performed by a pressure tool typically used in conventional LCB processes. This reduces the cost of manufacturing such devices.

[0032] Figures 2A to 2C The following describes the various steps of a bonding method implemented by a bonding device according to a second embodiment of this application. For example, the bonding method may be performed by... Figures 1A to 1C The bonding device shown is implemented.

[0033] like Figure 2A As shown, the bonding apparatus is used to perform a bonding process to bond a semiconductor die 201 to a substrate 200. More specifically, the bonding apparatus includes a jig 210, a top cover 220 mounted above the jig 210, and a laser source 240 disposed above the top cover 220. The top cover 220 has a clamping element 221 and a light-transmitting element 222. Details of the bonding apparatus, the semiconductor die 201, and the substrate 200 can be found similar to those described in the section on... Figures 1A to 1C The details shown in the embodiments will not be elaborated further here for the sake of simplicity.

[0034] refer to Figure 2AA substrate 200 and a semiconductor die 201 are stacked between a top cover 220 and a clamp 210. Solder paste may be applied between the substrate 200 and the semiconductor die 201, and during subsequent bonding steps, the solder paste will be heated and reshaped to form solder bumps. In some embodiments, flux material may also be applied together with the solder paste. More specifically, the substrate 200 on which the semiconductor die 201 is mounted is placed on the clamp 210, and the periphery of the substrate 200 is supported by the clamp 210. Next, the top cover 220 is attached to the clamp 210, and the top cover may be attracted by a magnet 211 embedded in the clamp 210 to prevent displacement between the top cover 220 and the clamp 210. In some embodiments, a clamping element 221 is disposed on the clamp 210, covering a portion of the substrate 200, and a light-transmitting element 122 covers the semiconductor die 201. It is also understood that the clamping element 221 can be first attached to the fixture 210, and the light-transmitting element 122 can be placed in the opening of the clamping element 221 in a subsequent process.

[0035] like Figure 2A As shown, the clamp 210 also includes a channel 216 beneath the substrate 200. A bonding platform with a bottom cover 232 and a support block 230 attached to the bottom cover 232 may be provided, the bonding platform being spaced apart from the clamp 210. In some embodiments, the support block 230 has a venting channel throughout the support block 230 and is fluidly connected to a vacuum source 231.

[0036] Next, the bonding platform moves toward the fixture 210 and eventually attaches to the other side of the fixture 210, which is different from the position of the top cover 220, as shown. Figure 2B As shown in the diagram. In this configuration, the support block 230 can be accommodated within the channel 216 of the clamp 210 to support the substrate 200, and the bottom cover 232 is attached to the bottom surface of the clamp 210. The bottom cover 232 may contain the same material as the clamping element 221, and the bottom cover can be attracted by the magnet 211 within the clamp 210.

[0037] Next, a bonding step is performed to bond the semiconductor die 201 to the substrate 200. More specifically, a vacuum source 231 can be turned on to apply vacuum pressure, thereby adsorbing and fixing the substrate 200 through the ventilation channels. Figure 2CAs shown, a laser source 240 can be turned on to emit a laser beam toward the semiconductor die 201. The laser beam passes through the light-transmitting element 122 to reach the semiconductor die 201, heating and reshaping the solder paste to form desired solder bumps and establish a sufficient bond between the semiconductor die 201 and the substrate 200. During the bonding step, the clamping element 221 can press a portion of the substrate 200 against the jig 210, and the light-transmitting element 122 can press the semiconductor die 201 against the substrate 200, thereby reducing warpage of the semiconductor die 201 and the substrate 200, improving the bonding quality between the semiconductor die 201 and the substrate 200, and thus enhancing the performance of the device thus produced. After the bonding step, the bonding platform can be removed from the jig 210 to create sufficient space for subsequent processes. In some embodiments, subsequent underfill or encapsulation processes can be performed on the bonded semiconductor die 201 and the substrate 200.

[0038] The bonding method using the bonding equipment described above can be used in any chip assembly process where the chip assembly process is expected to produce less warpage when exposed to heating processes such as bonding and reflow, and thus better control of package thickness, achieving better device performance and a larger process window.

[0039] Although exemplary bonding devices of this application have been described in conjunction with the accompanying drawings, those skilled in the art will understand that modifications and adjustments can be made to the bonding devices without departing from the scope of the invention.

[0040] Various embodiments have been described herein with reference to the accompanying drawings. However, it will be apparent that various modifications and alterations can be made thereto, and additional embodiments may be implemented without departing from the broader scope of the invention as set forth in the appended claims. Furthermore, other embodiments will be apparent to those skilled in the art upon consideration of the description and practice of one or more embodiments of the invention disclosed herein. Therefore, the examples in this application and herein are intended to be considered exemplary only, and the true scope and spirit of the invention are indicated by the list of exemplary claims appended.

Claims

1. A bonding apparatus, characterized in that, include: A clamp configured to support the periphery of a substrate having a semiconductor die mounted thereon; A top cover operably attached to the clamp, and the top cover being configured to cover the substrate and the semiconductor die when attached to the clamp, wherein the top cover includes: A clamping element operably attached to the clamp, the clamping element being configured to cover a portion of the substrate when the top cover is attached to the clamp to reduce warpage of the substrate, wherein the clamping element includes an opening at the center of the clamping element and the opening is configured to receive and expose the semiconductor die; and A light-transmitting element is mounted within the opening, and the light-transmitting element is configured to cover the semiconductor die when the top cover is attached to the fixture to reduce warpage of the semiconductor die and allow a laser beam to pass through the light-transmitting element to reach the semiconductor die; and A laser source configured to emit a laser beam that passes through the light-transmitting element to reach the semiconductor die.

2. The bonding apparatus according to claim 1, characterized in that, The clamp includes at least one magnet embedded within the clamp and configured to attract the clamping element when the top cover is attached to the clamp.

3. The bonding apparatus according to claim 2, characterized in that, The clamping element may be made of carbon steel or stainless steel.

4. The bonding apparatus according to claim 1, characterized in that, The light-transmitting element includes fused silica, CaF2, MgF2, crystalline silica, or ZnSe.

5. The bonding apparatus according to claim 4, characterized in that, The laser beam emitted by the laser source includes infrared radiation with a wavelength range of 900 nm to 1000 nm.

6. The bonding apparatus according to claim 1, characterized in that, The clamp includes a channel beneath the substrate, and the bonding apparatus further includes: A bonding platform operably attached to a side of the fixture opposite to the top cover, and the bonding platform being configured to support the substrate together with the fixture when attached to the fixture, wherein the bonding platform includes: Bottom cover; and A support block, attached to the bottom cover and configured to be received within the channel of the fixture, such that when the bonding platform is attached to the fixture, the support block supports the substrate.

7. The bonding apparatus according to claim 6, characterized in that, The support block has multiple ventilation channels that are fluidly connected to a vacuum source to apply vacuum pressure to the substrate when the support block supports the substrate.

8. A bonding method, characterized in that, The bonding method is performed by a bonding apparatus, the bonding apparatus comprising: a clamp; a top cover above the clamp, wherein the top cover includes a clamping element having an opening and a light-transmitting element disposed within the opening; and a laser source, and wherein the method comprises: A substrate is placed between the top cover and the clamp, the substrate having a semiconductor die mounted thereon, wherein the clamp supports the periphery of the substrate and the top cover is attached to the clamp, wherein the clamping element covers a portion of the substrate and the light-transmitting element covers the semiconductor die; and A laser beam is emitted from the laser source through the light-transmitting element to the semiconductor die, thereby bonding the semiconductor die to the substrate via solder bumps. The clamping element presses a portion of the substrate toward the clamp to reduce warping of the substrate, and the light-transmitting element presses the semiconductor die toward the substrate to reduce warping of the semiconductor die.

9. The bonding method according to claim 8, characterized in that, The light-transmitting element includes fused silica, CaF2, MgF2, crystalline silica, or ZnSe.

10. The bonding method according to claim 9, characterized in that, The laser beam comprises infrared radiation with a wavelength range between 900 nm and 1000 nm.

11. The bonding method according to claim 8, characterized in that, The fixture includes a channel beneath the substrate, and the method further includes, before emitting a laser beam through the light-transmitting element to the semiconductor die via the laser source: A bonding platform having a bottom cover and a support block attached to the bottom cover is attached to a side of the clamp that is not in the position of the top cover, so that the bonding platform and the clamp together support the substrate, wherein... The support block is accommodated within the channel of the clamp, such that the support block supports the substrate.

12. The bonding method according to claim 11, characterized in that, The support block has multiple ventilation channels that are fluidly connected to a vacuum source, and the method further includes applying a vacuum pressure to the substrate while the support block supports the substrate.

13. The bonding method according to claim 11, characterized in that, After bonding the semiconductor die to the substrate, the method further includes removing the bonding platform from the jig.

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