Temporary bonding substrate and method for manufacturing temporary bonding substrate

Abstract

Provided is a temporary bonding substrate that suitably suppresses the formation of cracks when a semiconductor chip is mounted. The temporary bonding substrate is composed of a ceramic sintered body and has a predetermined bonded object temporarily bonded to one main surface thereof. The temporary bonding substrate comprises, in at least a part of an outer peripheral portion that is an annular portion ranging up to a predetermined width from a side end portion, a Mg abundant region in which the abundance ratio of a magnesium compound is higher than that in a main portion that is the portion other than the outer peripheral portion.

Description

Temporary fixing substrate and method for manufacturing a temporary fixing substrate

[0001] This invention relates to a temporary fixing substrate used in the manufacturing process of semiconductor packages.

[0002] One example of semiconductor package manufacturing technology is FOWLP (Fan-out Wafer Level Package) technology. FOWLP technology generally involves the steps of: performing resin molding on a temporary substrate to which a semiconductor chip is temporarily fixed with adhesive; grinding the resin mold to expose the electrode ends of the semiconductor chip; forming a thin film redistribution layer (multilayer wiring) and solder balls on the surface where the electrode ends are exposed; and separating individual packages and peeling them from the temporary substrate, thereby obtaining a semiconductor package that is lower in height than conventional packages.

[0003] In the FOWLP technology, an embodiment using a translucent ceramic substrate as a temporary fixing substrate for the chip is already known (see, for example, Patent Document 1). The translucent ceramic substrate possesses all the requirements for a temporary fixing substrate, including high flatness necessary for electrode end exposure, high rigidity and reverse curvature necessary for suppressing warping during multilayer wiring formation, translucency that allows laser light for curing the adhesive to pass through, and chemical resistance for cleaning and reuse after use.

[0004] However, conventional temporary fixing substrates had a problem in that cracks would develop and propagate from the outer edge toward the side edge when semiconductor chips were mounted (temporarily fixed) onto them. When semiconductor chips are mounted onto a temporary fixing substrate, both the temporary fixing substrate, which is adsorbed and fixed to a predetermined support base, and the semiconductor chip to be mounted are heated. It is believed that the cracks are caused by thermal shock due to the temperature difference between the temporary fixing substrate and the semiconductor chip. Furthermore, it has been confirmed that such cracks are more likely to occur the closer the chip is mounted to the outer edge of the temporary fixing substrate, and are particularly likely to occur around the notch (notch area) when a notch is provided on the outer edge.

[0005] Patent No. 6430081

[0006] The present invention has been made in view of the above problems, and aims to realize a temporary fixing substrate that effectively suppresses the occurrence of cracks when a predetermined object to be fixed, such as a semiconductor chip, is temporarily fixed.

[0007] To solve the above problems, a first aspect of the present invention is a temporary fixing substrate made of a sintered ceramic body, on which a predetermined object to be fixed is temporarily fixed on one main surface, comprising an outer peripheral portion which is an annular portion within a predetermined width range from the side edge, and a main portion which is the portion other than the outer peripheral portion, characterized in that at least a part of the outer peripheral portion is provided with an Mg-unevenly distributed region in which the abundance ratio of the magnesium compound is higher than the abundance ratio of the magnesium compound in the main portion.

[0008] A second aspect of the present invention is a temporary fixing substrate according to the first aspect, characterized in that a notch is provided at the side end, and the Mg-uneven region includes the portion where the notch is formed.

[0009] A third aspect of the present invention is a temporary fixing substrate according to the first or second aspect, characterized in that the entire outer periphery is the Mg-unevenly distributed region.

[0010] A fourth aspect of the present invention is a temporary fixing substrate according to the first or second aspect, characterized in that the concentration of the magnesium compound in the main portion, in terms of magnesia, is 400 ppm or less.

[0011] A fifth aspect of the present invention is a temporary fixing substrate according to the fourth aspect, characterized in that the concentration of the magnesium compound in the Mg-unevenly distributed region, in terms of magnesia, is 500 ppm or more.

[0012] A sixth aspect of the present invention is a temporary fixing substrate according to the first or second aspect, characterized in that the predetermined width range is 1% or more and 10% or less of the radius of the temporary fixing substrate.

[0013] A seventh aspect of the present invention is a temporary fixing substrate according to the first or second aspect, characterized in that the main component of the ceramic is alumina.

[0014] An eighth aspect of the present invention is a method for manufacturing a temporary fixing substrate on which a predetermined object to be fixed is temporarily fixed on one main surface, comprising: a molding step of producing a plate-shaped molded body containing ceramic powder; a pre-calcination step of pre-calcining the molded body in the atmosphere; an outer perimeter processing step of applying a Mg-containing substance to at least a portion of the outer perimeter of the calcined body after the pre-calcination step; a secondary calcination step of calcining the calcined body that has undergone the outer perimeter processing step in the atmosphere; and a final calcination step of firing the calcined body that has undergone the secondary calcination step in a hydrogen atmosphere to obtain a temporary fixing substrate which is a sintered ceramic body, wherein in the final calcination step, an Mg-uneven region is formed in at least a portion of the outer perimeter, which is an annular portion within a predetermined width range from the side edge of the temporary fixing substrate, corresponding to at least a portion of the outer perimeter of the calcined body to which the Mg-containing substance was applied in the outer perimeter processing step, in which the ratio of the magnesium compound is higher than the ratio of the magnesium compound in the main portion, which is a portion other than the outer perimeter.

[0015] A ninth aspect of the present invention is a method for manufacturing a temporary fixed substrate according to the eighth aspect, wherein the Mg-containing substance is an aqueous solution containing Mg, and in the peripheral treatment step, the aqueous solution containing Mg is permeated into at least a portion of the area by immersion in the aqueous solution containing Mg, dropping the aqueous solution containing Mg, or spray coating the aqueous solution containing Mg.

[0016] A tenth aspect of the present invention is a method for manufacturing a temporary fixed substrate according to the eighth or ninth aspect, characterized in that the main component of the ceramics is alumina.

[0017] According to the first to tenth aspects of the present invention, the occurrence of cracks in a temporary fixing substrate when a predetermined object to be fixed, such as a semiconductor chip, is temporarily fixed is suitably suppressed.

[0018] Figure 1 is a plan view of the surface 1a of the temporary fixing substrate 1. Figure 2 is a schematic flow diagram showing the manufacturing process of the temporary fixing substrate 1. Figure 3 is a schematic diagram showing the spray coating of the Mg-containing aqueous solution. Figure 4 is a schematic diagram showing the crack test.

[0019] <Temporary Fixing Substrate> Figure 1 is a plan view of one main surface (surface) 1a of a temporary fixing substrate 1, which is one embodiment of the support substrate according to the present invention. The temporary fixing substrate 1 is a substrate on which a semiconductor chip is temporarily fixed when manufacturing a semiconductor package using FOWLP (Fan-out Wafer Level Package) technology, for example.

[0020] The temporary fixed substrate 1 is a disc-shaped translucent ceramic substrate with a diameter of several hundred mm (e.g., 300 mm), a thickness of several hundred μm to several mm (e.g., 1 mm), an in-plane thickness difference of several μm or less (e.g., within 3 μm), and a warp of several hundred μm or less (e.g., 200 μm).

[0021] In this embodiment, a translucent ceramic is defined as a ceramic having a forward total light transmittance (hereinafter also simply referred to as transmittance) of 20% or more across the entire wavelength range from 200 nm to 1500 nm. Examples of such translucent ceramics include alumina, silicon nitride, aluminum nitride, and silicon oxide.

[0022] For example, a sintered substrate mainly composed of alumina with a transmittance of 70% or more at a wavelength of 1000 nm is a suitable example of the temporary fixing substrate 1. When alumina is the main component, it is preferable to use high-purity alumina powder of 99.9% or more (preferably 99.95% or more) as the raw material, and to such alumina powder, magnesia (magnesium oxide, MgO) and zirconia (ZrO) as a sintering aid are added. ２ ) and Yttria (Y ２ O ３ It is preferable that ) be added.

[0023] The surface 1a, which is the placement surface of the semiconductor chip, and the other main surface (back surface) 1b are both pre-polished to become flat polished surfaces with low surface roughness. More specifically, the surface 1a and back surface 1b achieve an in-plane thickness difference of a few micrometers or less and an arithmetic mean roughness Ra of 100 nm or less (preferably 20 nm or less). More specifically, both the surface 1a and back surface 1b are surfaces that have been lapped. There is no particular limit to the lower limit of the arithmetic mean roughness Ra of the surface 1a and back surface 1b, but 1 nm is sufficient for practical purposes.

[0024] The grain size (average grain size) of the temporary fixing substrate 1 is preferably 4.5 μm or more and 50 μm or less. The average grain size is set to 4.5 μm or more to ensure light transmission, and to 50 μm or less to ensure the strength of the temporary fixing substrate 1. Unless otherwise specified, the ceramic particles and their grain size (average grain size) refer to the particles and grain size (average grain size) of the main component ceramics.

[0025] Furthermore, the temporary fixing substrate 1 may have a notch (cutout) 1n at a predetermined position on the side edge 1e for use in positioning and other purposes in subsequent processes. Figure 1 shows the shape of the side edge 1e when such a notch 1n is provided with a solid line, and the shape of the side edge 1e before such a notch 1n is provided (or when the notch 1n is not provided) with a dashed line. In this embodiment, unless otherwise specified, the temporary fixing substrate 1 with the notch 1n is also simply referred to as the temporary fixing substrate 1.

[0026] In addition, in the temporary fixing substrate 1 according to this embodiment, the outer peripheral portion 2, which is an annular portion within a predetermined width a range from the side edge 1e, is made into a Mg-unevenly distributed region RE in which the proportion of magnesium (Mg) compounds is higher (higher concentration) compared to the portion other than the outer peripheral portion 2 (hereinafter also referred to as the main portion 1m). In this embodiment, the proportion of magnesium compounds is evaluated in terms of the value converted to magnesia (magnesium oxide, MgO), which is an oxide of Mg. Therefore, the proportion of magnesium compounds is sometimes referred to as the magnesia concentration.

[0027] The Mg-uneven region RE is a region where the uneven distribution of magnesium compounds at the grain boundaries of the polycrystalline structure of the temporary fixed substrate 1, which is composed mainly of ceramics (e.g., alumina), is more pronounced compared to the main part 1m. The magnesium compounds are mainly spinel (MgAl ２ O ４ ) and magnesia is given as an example.

[0028] The Mg-unevenly distributed region RE is intentionally provided to prevent cracks from occurring in the temporary fixing substrate 1 during the semiconductor chip mounting (temporary fixing) process, which is one of the steps in the semiconductor package manufacturing process when the temporary fixing substrate 1 is used.

[0029] Conventionally, the presence of spinel at the grain boundaries of the temporary fixing substrate 1 was thought to reduce the strength of the temporary fixing substrate 1. However, after diligent research by the inventors of the present invention, it was confirmed that the presence of spinel at the grain boundaries reduces the Young's modulus and has a stress-relieving effect when the temporary fixing substrate 1 is considered as a composite material of the main component ceramics and spinel.

[0030] In this embodiment, taking into consideration the above findings and the fact that cracks tend to occur from the outer peripheral portion 2 to the side edge 1e of the temporary fixing substrate 1 when mounting semiconductor chips, the outer peripheral portion 2 of the temporary fixing substrate 1 is made into an Mg-unevenly distributed region RE in which spinel is mainly unevenly distributed at the grain boundary. As a result, in the temporary fixing substrate 1 according to this embodiment, the stress caused by thermal shock that occurs when semiconductor chips are mounted is suitably relieved in the Mg-unevenly distributed region RE. Consequently, in the temporary fixing substrate 1 according to this embodiment, the occurrence of cracks from the outer peripheral portion 2 to the side edge 1e is suitably suppressed.

[0031] More specifically, the magnesium concentration in the main portion 1m is usually around 10 ppm to 400 ppm, while the magnesium concentration in the Mg-unevenly distributed region RE is set to 500 ppm or higher. A magnesium concentration exceeding 400 ppm in the main portion 1m is undesirable because it reduces the strength of the temporary fixed substrate 1. Furthermore, a magnesium concentration below 500 ppm in the Mg-unevenly distributed region RE is undesirable because it prevents the aforementioned crack formation suppression effect from being adequately achieved.

[0032] The width a of the outer peripheral portion 2, which is designated as the Mg-unevenly distributed region RE, should be 1% or more and 10% or less of the radius r of the temporary fixing substrate 1, and is preferably larger than the width of the notch 1n in the radial direction of the temporary fixing substrate 1.

[0033] The formation of the Mg-unevenly distributed region RE is carried out during the manufacturing process of the temporary fixed substrate 1, which will be described later. Various methods can be applied to form the Mg-unevenly distributed region RE.

[0034] In the case of a temporary fixed substrate 1 provided with a notch 1n, the Mg-uneven region RE is provided so as to include the area where the notch 1n exists (so that the notch 1n fits within the width of the Mg-uneven region RE). This is because stress is concentrated particularly near the notch 1n within the outer peripheral portion 2, and there is a high risk of crack formation.

[0035] Alternatively, if a notch 1n is provided, instead of making the entire outer peripheral portion 2 the Mg-unevenly distributed region RE, at least a predetermined range of the notch portion 2n, including the area where the notch 1n exists, may be made the Mg-unevenly distributed region RE. However, in this case, in order to suppress the risk of crack formation outside the notch portion 2n, it is preferable that the grain size of the main portion 1m and the outer peripheral portion 2 other than the notch portion 2n be 5 μm or less.

[0036] In this embodiment, the notch portion 2n is defined as a part of the temporary fixing substrate 1 that includes at least the notch 1n, and is a sector-shaped region with a central angle θ having a common center O and radius r with the temporary fixing substrate 1, and extending a predetermined width a from the side end 1e. The central angle θ may be appropriately determined according to the shape and size of the notch 1n.

[0037] <Manufacturing Process of Temporary Fixing Substrate> Next, an example of the manufacturing process of the temporary fixing substrate 1 including the Mg uneven region RE will be described. FIG. 2 is a flowchart schematically showing the manufacturing process of such a temporary fixing substrate 1. The temporary fixing substrate 1 is generally manufactured through a molded body production step (step S1), a preliminary calcination step (step S2), an outer periphery processing step (step S3), a secondary calcination step (step S4), a main calcination step (step S5), an end processing step (step S6), and a polishing step (step S4).

[0038] In manufacturing the temporary fixing substrate 1, first, a molded body mainly composed of ceramic powder is produced (step S1). From the viewpoint of suitably ensuring the light transmittance in the temporary fixing substrate 1, it is preferable to use high-purity ceramic powder. Examples of the method for producing the molded body include known methods such as the mold casting method, the tape casting method, the doctor blade method, and the extrusion method.

[0039] Next, the produced molded body is preliminarily calcined (step S2). The preliminary calcination step is preferably performed at a temperature of 1000°C to 1300°C in the atmosphere. In the preliminary calcination step, organic components are desorbed, and a disk-shaped ceramic calcined body close to the temporary fixing substrate 1 is obtained.

[0040] Such a disk-shaped ceramic calcined body is subjected to outer periphery processing (step S3). The outer periphery processing is a process performed on the portion of the outer periphery of the ceramic calcined body obtained by preliminary calcination corresponding to the Mg uneven region RE in the temporary fixing substrate 1 in order to provide the final temporary fixing substrate 1 with the Mg uneven region RE.

[0041] In the present embodiment, as the outer periphery processing, by performing a process of intentionally applying a Mg-containing substance from the outside to the outer peripheral portion of the ceramic calcined body, a desired Mg uneven region RE is formed in the outer peripheral portion 2 of the finally obtained temporary fixing substrate 1. The Mg-containing substance is, for example, a solution or paste containing a Mg compound.

[0042] The Mg-containing substance may be applied to a location in the outer peripheral portion 2 corresponding to the Mg-enriched region RE where its presence is desired in the finally obtained temporary fixing substrate 1. For example, when only the notch portion 2n is defined as the Mg-enriched region RE, the Mg-containing substance may be applied only to the location corresponding to the notch portion 2n in the ceramic green body.

[0043] As one aspect of such outer peripheral processing, an infiltration process in which a predetermined Mg-containing aqueous solution is infiltrated into the interior of the ceramic green body at the outer peripheral portion of the ceramic green body is exemplified. Examples of the Mg-containing aqueous solution include magnesium nitrate (Mg(NO ３ ) ２ )aqueous solution. The concentration of the aqueous solution when these aqueous solutions are used may be from 0.1 wt% to 50 wt%. Also, as specific methods of the infiltration process, various methods such as immersion of the treatment target location in the Mg-containing aqueous solution, dropping or spray coating of the Mg-containing aqueous solution onto the location by a dispenser are exemplified. It has been experimentally confirmed in advance that the Mg-enriched region RE is preferably formed by such treatment.

[0044] Further, as another aspect of the outer peripheral processing, a coating process in which a paste containing a Mg-containing substance (for example, magnesia) is applied to the outer peripheral portion of the ceramic green body by a method such as printing is also exemplified.

[0045] The sintered body subjected to these outer peripheral processes is subjected to a secondary pre-firing process (step S4) under the same conditions as the preliminary pre-firing process, and then to a main firing process (step S5) in a hydrogen atmosphere with the firing temperature set to 1600°C to 1900°C. Thereby, the temporary fixing substrate 1 provided with the Mg-enriched region RE is obtained.

[0046] Incidentally, following the main firing process, for the purpose of adjusting (correcting) warpage, the obtained temporary fixing substrate 1 may be further annealed in a hydrogen furnace. The annealing process is preferably carried out at a temperature within ±100°C of the maximum temperature during the main firing, more preferably at 1900°C or lower, from the viewpoint of preventing deformation and abnormal grain growth and promoting the discharge of the sintering aid. Also, the annealing time is preferably 1 to 6 hours.

[0047] The obtained temporary fixing substrate 1 is subjected to an end processing step (step S6) and further a polishing step (step S4). As the end processing step, chamfering (bevelling) of the side end portion 1e, formation of the notch 1n, etc. are performed. In the polishing step, grinding of the front surface 1a and the back surface 1b by a grinder and lapping using diamond abrasive grains are performed.

[0048] By going through the above steps, a temporary fixing substrate 1 in which the outer peripheral portion 2 or the notch portion 2n is a high-strength Mg-rich region RE is obtained. That is, a temporary fixing substrate 1 in which the occurrence of cracks when mounting a semiconductor chip is suitably suppressed is obtained.

[0049] A test for confirming the effect of crack suppression due to the provision of the Mg-rich region RE was conducted. Specifically, two types of temporary fixing substrates 1 (Example 1 and Example 2) in which the entire outer peripheral portion 2 is the Mg-rich region RE and the combination of the magnesia concentration of the main portion 1m and the magnesia concentration of the outer peripheral portion 2 are different, and one type of temporary fixing substrate 1 (Comparative Example 1) without the Mg-rich region RE were produced according to the flow of FIG. 2, and a test simulating the mounting of a semiconductor chip was conducted to evaluate the presence or absence of crack generation.

[0050] The raw material composition of the slurry for obtaining the molded body was made common in Example 1, Example 2, and Comparative Example 1 as follows.

[0051] (Ceramic powder) α-alumina (purity 99.99%): 100 parts by weight; magnesia (MgO): 350 ppm; zirconia (Zr ２ ): 500 ppm; yttria (Y ２ O ３ ): 10 ppm.

[0052] (Dispersion medium) 2-ethylhexanol: 45 parts by weight.

[0053] (Binder) PVB resin: 4 parts by weight.

[0054] (Dispersant) Polymer surfactant: 3 parts by weight.

[0055] (Plasticizer) DOP: 0.1 parts by weight.

[0056] In all cases, the molded body was fabricated in a disc shape using the doctor blade method. Specifically, the slurry was molded into a rectangular shape and then cut out in a circular shape so that the final temporary fixed substrate would have a thickness of 1.1 mm and a diameter of 300 mm.

[0057] The resulting molded body was pre-fired at 1300°C in air for 2 hours to obtain a calcined body.

[0058] Next, in Examples 1 and 2, a magnesium nitrate aqueous solution was used as the Mg-containing aqueous solution, and the magnesium nitrate aqueous solution was spray-coated onto the outer circumference of the disc-shaped ceramic calcined body after pre-calcination.

[0059] Figure 3 schematically shows the spray coating process of an aqueous solution containing magnesium. Spray coating of an aqueous solution containing magnesium can be performed, for example, by placing a ceramic calcined body 1α, with both main surfaces covered by a mask 102 except for the outer peripheral portion 2α of width a, on a horizontally rotatable turntable 101, and spraying the aqueous solution L containing magnesium from a spray gun 103 toward the outer peripheral portion 2α while rotating the turntable 101. In all of the examples, the value of width a was set to 5 mm, and the combination of the concentration of the magnesium aqueous solution and the spraying time was varied as follows.

[0060] Example 1: 20%, 90 seconds; Example 2: 40%, 120 seconds.

[0061] These ceramic calcined bodies, after spray coating, underwent secondary calcination. The conditions for secondary calcination were the same as those for preliminary calcination. Then, each ceramic calcined body after secondary calcination was subjected to final calcination at 1800°C for 2.5 hours under a hydrogen atmosphere to obtain temporary fixed substrate 1. The final calcination process was carried out by placing the ceramic calcined bodies after secondary calcination on a molybdenum plate.

[0062] The surface 1a and back surface 1b of the temporary fixed substrate 1 after the final firing were further subjected to grinding with a grinder and lapping with diamond abrasive grains to adjust the thickness to 1.0 mm.

[0063] The temporary fixed substrate 1 of Comparative Example 1 was prepared under the same conditions as in Example 1, except that the Mg-containing aqueous solution was spray-coated and the amount of magnesia powder added was 450 ppm.

[0064] In the manner described above, multiple temporary fixing substrates 1 were fabricated for each of Example 1, Example 2, and Comparative Example 1.

[0065] The main portion 1m and outer peripheral portion 2 of the temporary fixing substrate 1 obtained in Example 1, Example 2, and Comparative Example 1 were crushed, and then their composition was analyzed by ICP to measure the magnesia concentration.

[0066] Furthermore, crack tests were conducted on the temporary fixed substrate 1 of Example 1, Example 2, and Comparative Example 1. Figure 4 is a schematic diagram showing the crack test.

[0067] In the crack test, the temporary fixed substrate 1 was first placed horizontally on the chuck table 201. Then, with the chuck table 201 heated to 80°C, a rectangular load piece 202, which mimics the bonding head of a semiconductor chip, was lowered from above as indicated by arrow AR while being heated to 260°C, thereby pressing down on the temporary fixed substrate 1. The presence or absence of cracks caused by thermal shock resulting from this pressing was checked. These tests were performed on 10 temporary fixed substrates 1 for each of Example 1, Example 2, and Comparative Example 1, and the frequency of crack occurrence was evaluated.

[0068] The planar size of the load piece 202 was set to 3 cm × 3 cm, and the distance d from the center O of the temporary fixing substrate 1 to the center position C of the pressing was set to 12.5 cm. More specifically, the distance dx in the x-axis direction was 12.5 cm, and the distance dy in the y-axis direction was 0 cm. The pressing force was set to 5.4 N, resulting in a pressing pressure of 0.6 N / cm². ２ This was the result. The pressure value in question is larger than the pressure that acts on the temporary fixing substrate 1 when the semiconductor chip is actually mounted. In the case of Example 8, the center position C of the pressing was made as close as possible to the notch portion 2n.

[0069] Table 1 shows a list of the magnesia concentrations in the main portion 1m and outer peripheral portion 2 of the temporary fixing substrate 1 for Example 1, Example 2, and Comparative Example 1, along with the results of the crack test.

[0070]

[0071] If no cracks occur in any of the ten temporary fixing substrates 1, it is determined that the resistance to cracking is sufficient, and a circle ("○") is marked in the "Crack Test Results" column of Table 2.

[0072] On the other hand, if three or more temporary fixed substrates developed cracks, it was determined that the crack resistance was insufficient, and an "×" (cross mark) was placed in the "Crack Test Results" column of Table 2.

[0073] Furthermore, if only one or two temporary fixed substrates 1 developed cracks, it would be judged that the occurrence of cracks was suppressed to a degree that did not cause production problems. However, none of the cases in Example 1, Example 2, or Comparative Example 1 fell into this category.

[0074] As shown in Table 1, in both Example 1 and Example 2, the magnesia concentration in the outer peripheral portion 2 was greater than the magnesia concentration in the main portion 1m. In other words, in both Example 1 and Example 2, a temporary fixing substrate 1 was obtained in which a Mg-unevenly distributed region RE was provided in the outer peripheral portion 2.

[0075] Moreover, in these embodiments, no cracks occurred in the temporary fixed substrate 1.

[0076] On the other hand, in Comparative Example 1, where the magnesia concentration in the main portion 1m and the outer peripheral portion 2 were the same, cracks occurred in many of the temporary fixed substrates 1.

[0077] The above results demonstrate that by providing an Mg-unevenly distributed region RE on the outer peripheral portion 2 of the temporary fixed substrate 1, cracks during semiconductor chip mounting can be effectively suppressed.

Claims

1. A temporary fixing substrate made of a sintered ceramic body, on which a predetermined object to be fixed is temporarily fixed on one main surface, comprising: an outer peripheral portion which is an annular portion within a predetermined width range from the side edge; and a main portion which is the portion other than the outer peripheral portion, wherein at least a part of the outer peripheral portion is provided with an Mg-unevenly distributed region in which the abundance ratio of the magnesium compound is higher than the abundance ratio of the magnesium compound in the main portion.

2. A temporary fixing substrate according to claim 1, characterized in that a notch is provided at the side end, and the Mg uneven distribution region includes the portion where the notch is formed.

3. A temporary fixing substrate according to claim 1 or claim 2, characterized in that the entire outer periphery is the Mg-unevenly distributed region.

4. A temporary fixing substrate according to claim 1 or claim 2, characterized in that the concentration of the magnesium compound in the main portion, in terms of magnesia, is 400 ppm or less.

5. A temporary fixing substrate according to claim 4, characterized in that the concentration of the magnesium compound in the Mg-unevenly distributed region, in terms of magnesia, is 500 ppm or more.

6. A temporary fixing substrate according to claim 1 or claim 2, characterized in that the predetermined width range is 1% or more and 10% or less of the radius of the temporary fixing substrate.

7. A temporary fixing substrate according to claim 1 or claim 2, characterized in that the main component of the ceramic is alumina.

8. A method for manufacturing a temporary fixing substrate on which a predetermined object to be fixed is temporarily fixed on one main surface, comprising: a molding step of producing a plate-shaped molded body containing ceramic powder; a pre-calcination step of pre-calcining the molded body in the atmosphere; an outer perimeter processing step of applying a Mg-containing substance to at least a portion of the outer perimeter of the calcined body after the pre-calcination step; a secondary calcination step of calcining the calcined body that has undergone the outer perimeter processing step in the atmosphere; and a final calcination step of firing the calcined body that has undergone the secondary calcination step in a hydrogen atmosphere to obtain a temporary fixing substrate which is a sintered ceramic body, wherein in the final calcination step, an Mg-uneven region is formed in at least a portion of the outer perimeter, which is an annular portion within a predetermined width range from the side edge of the temporary fixing substrate, corresponding to at least a portion of the outer perimeter of the calcined body to which the Mg-containing substance was applied in the outer perimeter processing step, in which the ratio of the magnesium compound is higher than the ratio of the magnesium compound in the main portion which is a portion other than the outer perimeter.

9. A method for manufacturing a temporary fixed substrate according to claim 8, wherein the Mg-containing substance is an aqueous solution containing Mg, and in the peripheral treatment step, the aqueous solution containing Mg is permeated into at least a portion of the area by immersion in the aqueous solution containing Mg, dropping the aqueous solution containing Mg, or spray coating the aqueous solution containing Mg.

10. A method for manufacturing a temporary fixed substrate according to claim 8 or claim 9, characterized in that the main component of the ceramics is alumina.

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